KR100905628B1 - Active Agent Delivery Systems and Methods for Protecting and Administering Active Agents - Google Patents

Abstract

The present invention provides a composition comprising a polypeptide and an active agent covalently bound to the polypeptide. Also provided are methods of delivering an active agent to a patient comprising administering to the patient a composition comprising a polypeptide and an active agent covalently bound to the polypeptide. Also provided are methods of protecting an active agent from degradation, including covalently binding the active agent to the polypeptide. Also provided are methods of controlling release of an active agent from a composition comprising the polypeptide, comprising covalently binding the active agent to the polypeptide. (Figure 1)

Polypeptide, active agent, covalent bond, release of active agent, delivery system, enzyme catalyst

Description

Active Agent Delivery Systems and Methods for Protecting and Administering Active Agents

The present invention relates to an active agent delivery system, more specifically to a composition comprising a polypeptide covalently bound to the active agent and to a method for protecting and administering the active agent.

Active agent delivery systems are often important for effective delivery of biologically active agents (active agents) to suitable targets. The importance of such a system expands when patient compliance and active agent stability are considered. For example, if the active agent is administered orally instead of by injection or by another administration technique, patient compliance is expected to increase significantly. Increasing the stability of the active agent, such as prolonged shelf life or residual in the stomach, will ensure dosing reproducibility, and possibly even reduce the number of dosing necessary to improve patient compliance.

Absorption of the orally administered active agent is often blocked by a severely acidic gastric environment, potent digestive enzymes in the gastrointestinal tract, permeability of cell membranes and transport through the lipid bilayer. Incorporating excipients such as resorcinol, surfactants, polyethylene glycol (PEG) or bile acids improves the permeability of cell membranes. Microencapsulating the active agent with protenoid globules, liposomes or polysaccharides has been effective in reducing enzymatic degradation of the active agent. Enzyme inhibiting excipients have also been used to prevent enzymatic degradation. Enteric coating has been used as a protective agent for the stomach.

The active agent delivery system also provides the ability to control the release of the active agent. For example, diazepam can be combined with a copolymer of glutamic acid and aspartic acid to delay release of the active agent. In another example, a copolymer of lactic acid and glutaric acid is used to provide timed-release of human growth hormone. A wide range of drugs are known to provide delayed release by microencapsulating the active agent in amides, modified amino acids or thermally condensed amino acids of dicarboxylic acids. Sustained release additives may be mixed with the various active agents in tablet formulations.

Each of these techniques confers improved stability and on-time release properties to the active agent material. Unfortunately, these techniques have some disadvantages. Incorporation of active agents often depends on diffusion into the microencapsulation matrix, which may not be quantitative and may complicate administration reproducibility. In addition, encapsulated drugs rely on the diffusion of the matrix, which is highly dependent on the water solubility of the active agent. Conversely, the water soluble globules expand indefinitely, and unfortunately release the actives all at once so that the actives are hardly available for delayed release. Moreover, some techniques do not reliably control the degradation process required for activator release. For example, enteric-deposited active agents release the active agent depending on pH, in which case it is difficult to control the release rate.

In the past, amino acid side chains of polypeptides have been used as pendant groups to which an active agent can be bound. These techniques typically require the use of a spacer group between the amino acid pendant group and the active agent. Peptide-drug conjugates of this class of drug delivery systems depend on enzymes in the bloodstream for drug release, and in this case are not used for oral administration. Examples of on-time and targeted release of injectable or subcutaneous drugs include the binding of noretindron to gamma carboxylate of polyglutamic acid via hydroxypropyl spacer and nitrogen to gamma carbamide of polyglutamine through peptide spacer. There is a combination of mustards. Dexamethasone covalently bonded directly to the beta carboxylate of polyaspartic acid without a spacer group. This prodrug combination is designed as a colon-specific drug delivery system in which the drug is released by bacterial hydrolase present in the large intestine. The dexamethasone activator released was also targeted to treat colon disease and was not absorbed into the bloodstream. Another technique is to combine the covalent binding benefits of the drug with a liposome formulation where the active ingredient is bound to a well-ordered lipid membrane (known as HAR) via a peptide linker. Thus, none of the drug delivery systems reported so far introduces the concept of binding the active ingredient to the polypeptide pendant group to introduce targeted delivery into the bloodstream via oral administration.

It is also important to control the molecular weight, molecular size and particle size of the active agent delivery system. Mutable molecular weights have unpredictable diffusion rates and pharmacokinetics. High molecular weight carriers are digested slowly or lately, as in the case of naproxen-linked dextran, which is digested mostly in the colon by bacterial enzymes. High molecular weight globules usually have a high water content, which can be a problem if there are active ingredients that are unstable in water. Particle size is not only a problem for injectable drugs such as in the case of HAR applications, but is also limited to less than 5 microns of absorption through the intestinal chain membranes.

Summary of the Invention

The present invention provides covalent linkages of the active agent to the peptide or polymer of the amino acid. The present invention distinguishes the above-mentioned technology by covalently binding an active agent, including, for example, pharmaceutical and nutritional agents, to the N-terminus, C-terminus or directly to the amino acid side chain of an oligopeptide or polypeptide, also referred to herein as a carrier peptide. do. In certain applications, the polypeptide will stabilize the active agent primarily through morphological protection in the stomach. In these applications, the transport of the active agent is controlled in part by the kinetics of unfolding the carrier peptide. Upon introduction into the upper intestine, the native enzyme selectively hydrolyzes the peptide bonds of the carrier peptide to release the active ingredient for absorption by the body. This enzymatic action introduces a second sustained release mechanism.

The present invention provides a composition comprising a polypeptide and an active agent covalently bound to the polypeptide. Preferably, the polypeptide comprises (i) an oligopeptide, (ii) 20 natural amino acids (L or D isomers), homopolymers of one of its isomers, analogs or derivatives, (iii) two or more natural amino acids (L or D isomer), an isomer, analog or derivative thereof, (iv) a homopolymer of synthetic amino acid, (v) a heteropolymer of two or more synthetic amino acids, or (vi) one or more natural amino acids and one or more synthetic amino acids Heteropolymer of.

The active agent is preferably covalently linked to the side chain, N-terminus or C-terminus of the polypeptide. In a preferred embodiment, the active agent is a carboxylic acid and covalently linked to the N-terminus of the polypeptide. In another preferred embodiment, the active agent is an amine and covalently linked to the C-terminus of the polypeptide. In another preferred embodiment, the active agent is an alcohol and covalently linked to the C-terminus of the polypeptide. In another preferred embodiment, the active agent is an alcohol and covalently linked to the N-terminus of the polypeptide.

In addition, the compositions of the present invention may comprise one or more of microencapsulating agents, adjuvants and pharmaceutically acceptable excipients. The microencapsulating agent can be selected from polyethylene glycol (PEG), amino acids, sugars and salts. When an adjuvant is included in the composition, the adjuvant preferably activates an enteric transporter.

Preferably, the compositions of the present invention are in the form of ingestible tablets, intravenous preparations or oral suspensions. The active agent can be morphologically protected by allowing the polypeptide to fold around the active agent. In another embodiment, the polypeptide may release the active agent from the composition in a pH dependent manner.

The present invention also provides a method of protecting an active agent from degradation, comprising covalently binding the active agent to the polypeptide.

The present invention also provides a method of controlling the release of an active agent from a composition comprising the polypeptide comprising covalently binding the active agent to the polypeptide.

The present invention also provides a method of delivering an active agent to a patient, comprising administering the polypeptide and a composition comprising the active agent covalently bound to the polypeptide to a human or non-human animal patient. In a preferred embodiment, the active agent is released from the composition by enzyme catalyzed release. In another preferred embodiment, the active agent is released in a time dependent manner based on the pharmacokinetics of the enzyme catalyzed release. In another preferred embodiment, the composition further comprises a microencapsulating agent and the active agent is released from the composition by dissolution of the microencapsulating agent. In another preferred embodiment, the active agent is released from the composition by pH dependent development of the polypeptide. In another preferred embodiment, the active agent is released from the composition in sustained release. In another preferred embodiment, the composition further comprises an adjuvant covalently bound to the polypeptide and the release of the adjuvant from the composition is controlled by the polypeptide. Adjuvants can be microencapsulated into carrier peptide-drug conjugates for biphasic release of the active ingredient.

The present invention also provides a method of preparing a composition comprising the polypeptide and an active agent covalently bound to the polypeptide. This way

(a) attaching the active agent to the side chain of the amino acid to form the active agent / amino acid complex,

(b) forming an activator / amino acid complex N-carboxyhydride (NCA) from the activator / amino acid complex, and

(c) polymerizing the activator / amino acid complex N-carboxyhydride (NCA)

It includes.

In another preferred embodiment, the active agent is a pharmaceutical formulation or adjuvant. In another preferred embodiment, steps (a) and (b) are repeated before step (c) using a second active agent. If steps (a) and (b) are repeated before step (c) using the second agent, the active agent and the second active agent may be copolymerized in step (c). In another preferred embodiment, the amino acid is glutamic acid and the active agent is released from glutamic acid as a dimer upon hydrolysis of the polypeptide, wherein the active agent is released from glutamic acid by simultaneous intramolecular amine exchange reaction. In another preferred embodiment, glutamic acid is replaced by an amino acid selected from the group consisting of aspartic acid, arginine, asparagine, cysteine, lysine, threonine and serine, wherein the active agent is attached to the side chain of the amino acid to form amides, thioesters, To form esters, ethers, urethanes, carbonates, anhydrides or carbamates. In another preferred embodiment, glutamic acid is replaced by synthetic amino acids having pendant groups comprising amine, alcohol, sulfhydryl, amide, urea or acid functionality.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are not intended to limit the invention.

The present invention provides several advantageous advantages in the active agent delivery. First, the present invention can stabilize the active agent and prevent digestion in the stomach. In addition, drug effects may be prolonged by delayed release of the active agent. Moreover, active agents can be combined to produce a synergistic effect. In addition, the absorption of the active agent may be enhanced in the intestine. In addition, the present invention enables targeted delivery of active agents to specific sites of action.

The composition of the present invention includes a polypeptide and an active agent covalently bound to the polypeptide. Active agents can be selected from the list shown in Table 1, alone or in combination with other agents on the list.

Preferably, the polypeptide comprises (i) an oligopeptide, (ii) one of the 20 natural amino acids (L or D isomers), or an homopolymer of an isomer, analog or derivative thereof, and (iii) a natural 20 amino acids (L or D). Isomers of two or more amino acids, or isomers, analogs or derivatives thereof, (iv) homopolymers of synthetic amino acids, (v) heteropolymers of two or more synthetic amino acids, or (vi) one or more natural amino acids Heteropolymers of one or more synthetic amino acids.

Proteins, oligopeptides and polypeptides are polymers of amino acids having primary, secondary and tertiary structures. The secondary structure of a protein is the local form of the polypeptide chain and consists of a helix, pleated sheet and turn. The amino acid sequence of the protein and the structural constraints on the chain form determine the spatial arrangement of the molecule. The folding of the secondary structure and the spatial arrangement of the side chains form the tertiary structure.

Due to the dynamics between the atoms and solvent molecules of neighboring proteins, the proteins collapse. The thermodynamics of protein folding and unfolding are limited by the free energy under certain conditions of the protein, depending on the particular model. The process of protein folding involves, in particular, the packing of amino acids to form a hydrophobic core. The amino acid side chains inside the protein core occupy the same volume as in amino acid crystals. Thus, the folded protein interior is more like crystalline solids than oil droplets, and the solid reference state is the optimal model for determining the forces involved in protein stability.

Key forces involved in the thermodynamics of protein folding include van der Waals interactions, hydrogen bonding, electrostatic interactions, morphological entropy and hydrophobic effects. In view of protein stability, the hydrophobic effect refers to the energetic result of removing nonpolar groups from inside the protein and exposing it to water. When comparing amino acid hydrolysis energy to protein folding in the solid reference state, the hydrophobic effect acts as the dominant force. Hydrogen bonds are formed during protein folding, and intramolecular bonds are formed through hydrogen bonding with water. Water molecules are "released" from the packed hydrophobic protein core. All these forces combine to contribute to the overall stability of the folded protein, and the degree of occurrence of the ideal packing determines the relative stability of the protein. Maximal packing results in hydrophobic cores that are maximally masked from the residue center, or solvent.

Because hydrophobic agents can bind to the hydrophobic core of the peptide, energy is required to release the peptide before the drug is released. The annealing process needs to overcome the hydrophobic effect by hydration of the amino acid or acquisition of the protein melting temperature. The heat of hydration destabilizes the protein. Typically, the folded state of a protein requires only 5-15 kcal / mole of energy than the unfolded state. Nevertheless, protein unwinding at neutral pH and room temperature requires chemical reagents. In fact, partial loosening of proteins is often found before the start of irreversible chemical or structural processes. Protein structures also generally regulate the rate and extent of harmful chemical reactions.

Structural protection of the active agent by the protein depends on the stability of the folded state of the protein and the thermodynamics associated with reagent degradation. The conditions required for reagent digestion should be different from those for protein annealing.

The choice of amino acids depends on the desired physical properties. For example, if one wants to increase volume or lipophilic, the amino acids of the following table are added to the polypeptide carrier. On the other hand, polar amino acids can be selected to increase the hydrophilicity of the polypeptide.

Amino acids to be ionized may be selected for pH controlled peptide unwinding. Aspartic acid, glutamic acid and tyrosine have a neutral charge in the stomach but are ionized in the intestine. In contrast, basic amino acids such as histidine, lysine and arginine are ionized in the stomach and neutral in alkaline environments.

To select an amino acid sequence suitable for a given use, other factors can be used, such as π-π interaction between aromatic residues, twisting of the peptide chain due to the addition of proline, disulfide crosslinks and hydrogen bonds. The order of the straight sequences can affect how to maximize this interaction and is important for determining the secondary and tertiary structure of the polypeptide.

In addition, amino acids with reactive side chains (eg, glutamic acid, lysine, aspartic acid, serine, threonine and cysteine) can be added to the same carrier peptide for attachment of various active agents or adjuvants. This is particularly useful when a synergy between two or more active agents is required.

As mentioned above, carrier compounds of various molecular weights can have a significant effect on the reaction rate of activator release. As a result, low molecular weight activator delivery systems are preferred. An advantage of the present invention is that the chain length and molecular weight of the polypeptide can be optimized according to the degree of structural protection desired. This feature can be optimized with respect to the primary release mechanism. Thus, another advantage of the present invention is that delayed release time can be influenced by an increase in the molecular weight of the carrier polypeptide. Another important advantage of the present invention is that the rate of release of the active agent is controlled primarily by enzymatic hydrolysis of the important bonds present between the carrier peptide and the active agent.

Dextran is the only polysaccharide known to have been studied as a macromolecular carrier for covalent binding of drugs in colon specific drug delivery. In general, it was possible to load drugs up to 1/10 of the total weight of drug-dextran conjugate. As mentioned earlier, polysaccharides are mainly digested in the colon and drug absorption is mainly limited to the colon. The present invention has two major advantages over dextran. First, since the peptide is hydrolyzed by any of several aminopeptidases found in the lumen of the small intestine or bound to a brush-border membrane, the release of the active agent and subsequent absorption is jejunum ) Or in the ileum. Secondly, since the molecular weight of the carrier molecule can be adjusted, the amount of active agent loading can be adjusted.

As a practical example, the table below lists the lipophilic amino acids (less than one water molecule) and the molecular weight of the selected analgesics and vitamins.

amino acid Molecular Weight Active agent Molecular Weight Glycine 57 Acetaminophen 151 Alanine 71 Vitamin B ₆ (Pyroxydine) 169 Valine 99 Vitamin C (ascorbic acid) 176 Leucine 113 aspirin 180 Isoleucine 113 Ibuprofen 206 Phenylalanine 147 Retinic acid 300 Tyrosine 163 Vitamin B ₂ (Riboflavin) 376 Vitamin D ₂ 397 Vitamin E (Tocopherol) 431

The lipophilic amino acids are preferred because the structural protection of the selected active agent based on the ease of covalent binding to the oligopeptides is important. 18 was subtracted from the molecular weight of the amino acid because it considered condensation of the amino acids into the polypeptide. For example, a tenmer of glycine linked to aspirin (molecular weight = 588) will have a total molecular weight of 750 and aspirin will account for 24% of the total weight of the active agent delivery composition, or more than twice the maximum drug weight of dextran. . This applies only when applied to the N- or C-terminus, for example when the activator is bound to a pendant group of decaglutamic acid, a drug of molecular weight 180, although not entirely practicable, has a 58% lower weight It can be thought of as having.

The alcohol, amine or carboxylic acid group of the active agent is covalently linked to the N-terminus, C-terminus or side chain of the oligopeptide or polypeptide. The position of the bond depends in part on the choice of functional group. For example, when the active agent is a carboxylic acid (eg aspirin), the N-terminus of the oligopeptide is the preferred point of binding, as shown in FIG. If the active agent is an amine (eg ampicillin), the C-terminus is the preferred binding point to obtain a stable peptide binding activator as shown in FIG. 2. In the C- and N-terminal examples above, the peptide is essentially extended by monomer units forming new peptide bonds. If the active agent is an alcohol, either the C-terminus or the N-terminus is the preferred point of attachment to obtain a stable composition. As shown in the above example where the alcohol, noethynedrone is bound to poly (hydroxypropylglutamine), the alcohol can be converted to alkylchloroformate using phosgen. Thus, the present invention relates to the reaction of an important intermediate with the N-terminus of the peptide carrier as shown in FIG. In addition, FIGS. 1-3 show the release of the active ingredient from the peptide carrier by the small intestine peptidase.

The alcohol may selectively bind to the gamma carboxylate of glutamic acid, after which the conjugate is covalently linked to the C-terminus of the peptide carrier. Since the glutamic acid-drug conjugate can be considered a dimer, this product adds two monomer units at the C-terminus of the peptide carrier, where the glutamic acid residue acts as a spacer between the peptide and the drug as shown in FIG. . Intestinal enzymatic hydrolysis of important peptide bonds releases glutamic acid-drug residues from the peptide carrier. The free amine of the newly formed glutamic acid residue will then undergo an intramolecular amine exchange reaction to release the active agent with the formation of pyroglutamic acid as shown in FIG. 5. Alternatively, the glutamic acid-drug dimer can be converted to glutamic acid N-carboxyhydride esters. This intermediate can then be polymerized as described above using a suitable initiator as shown in FIG. 4. The product of this polymerization is polyglutamic acid with the active ingredient bound to a plurality of pendant groups. Thus, the maximum drug load of the carrier peptide can be achieved. In addition, other amino acids-NCA can be copolymerized with gamma ester glutamic acid NCA to impart specific properties to the drug delivery system.

The present invention also provides a method of imparting the same mechanism of action to other polypeptides containing functional side chains. Examples include, but are not limited to, polylysine, polyasparagine, polyarginine, polyserine, polycysteine, polytyrosine, polythreonine and polyglutamine. This mechanism can be interpreted for these polypeptides via spacers or linkers of pendant groups, which are preferably terminated by glutamic acid-drug dimers. Carrier peptide-drug conjugates are distinguished from the prior art in that the primary release of drug residues does not depend on esterases but on peptidase. Alternatively, the active agent may be directly bound to the pendant group where several other enzymes inherent in the digestive tract may affect release.

Active agents can be covalently attached to the N-terminus, C-terminus or side chain of a polypeptide using known techniques. Examples of linking organic compounds to N-terminal peptides include naphthylacetic acid to LH-RH, coumarinic acid to opioid peptides, and 1,3-dialkyl-3-acyltriazine to tetragastrin and pentagastrin Some but not limited to. As another example, techniques are known for forming biotin linked peptides and acridine linked peptides.

Polypeptide carriers can be prepared using conventional techniques. A preferred technique is to copolymerize a mixture of amino acid N-carboxyhydrides. Alternatively, solid phase automated polypeptide synthesizers can be used if a specific arrangement is desired.

There is a possibility to further stabilize the polypeptide by adding a stabilizer to the composition. Stabilizers such as sugars, amino acids, polyethylene glycols (PEG) and salts have been found to prevent proteolysis. In another embodiment of the invention, the polypeptide-active agent, which is a carrier conjugated to a polysaccharide, amino acid complex PEG or salt, can be microencapsulated to confer release prior to the first grade of active agent.

There is evidence that hydrophilic compounds are effectively absorbed through the intestinal epithelium by specialized transporters. The entire membrane delivery system is inherently asymmetric and responds asymmetrically to the cofactor. Thus, it can be expected that excitation of the membrane delivery system relates to a kind of specialized adjuvant that results in localized delivery of the active agent. Seven enteric delivery systems are known, classified according to the physical properties of the delivered substrate. These include amino acids, oligopeptides, glucose, monocarboxylic acids, phosphates, bile acids and P-glycoprotein delivery systems, each with their own associated delivery mechanism. This mechanism may vary depending on the hydrogen ions, sodium ions, binding sites or other cofactors. The present invention also enables targeting of the mechanism of the intestinal epithelial delivery system to facilitate absorption of the active agent.

In another embodiment of the invention, the composition comprises one or more adjuvants to increase the bioavailability of the active agent. The addition of the adjuvant is particularly preferred when using an active agent which is poorly absorbed when not added. Suitable adjuvants include, for example, papain for releasing the catalytic domain of aminopeptidase-N into lumens; Glycorecogenizers that activate enzymes in BBM; Bile acids that adhere to the peptide and enhance the adsorption of the peptide.

Preferably, the resulting peptide-active agent combination is formulated into tablets using suitable excipients and can be wet granulated or dry compacted.

The present invention relates to a composition comprising a polypeptide covalently bound to an active agent and a method for protecting and administering the active agent, which provides advantageous advantages in the active agent delivery. For example, the present invention can stabilize the active agent and prevent digestion in the stomach. In addition, drug effects may be prolonged by delayed release of the active agent. Moreover, active agents can be combined to produce a synergistic effect. In addition, the absorption of the active agent may be enhanced in the intestine. In addition, the present invention enables targeted delivery of active agents to specific sites of action.

The compositions of the present invention can be prepared in the following examples, essentially as the formation of amides from acids and amines.

Acid / N-terminal conjugates (see FIG. 1)

Acid bioactive agents can be dissolved in DMF under nitrogen and cooled to 0 ° C. The solution can then be treated with diisopropylcarbodiimide and hydroxybenzotriazole followed by an amine peptide carrier. The reaction was then stirred at rt for 7 h and the urea byproduct was filtered off and then the product precipitated in ether was purified by gel permeation chromatography (GPC) or dialysis.

Amine / C-terminal conjugate (see FIG. 2)

The peptide carrier can be dissolved in DMF under nitrogen and cooled to 0 ° C. The solution can then be treated with diisopropylcarbodiimide and hydroxybenzotriazole followed by amine bioactive agent. The reaction was then stirred at rt for 7 h and the urea byproduct was filtered off and the product precipitated in ether was purified by GPC or dialysis.

Alcohol / N-terminal conjugates (see FIG. 3)

In the following examples, chloroformate was prepared by combining alcohol and triphosgene, and carbamate was prepared when reacted with the N-terminus of the peptide. Thus, the alcohol bioactive agent can be treated with triphosgene in anhydrous DMF under nitrogen. Appropriately protected peptide carrier was then added slowly and the solution was stirred for 7 hours at room temperature. The product was then precipitated in ether. The crude product was appropriately deprotected and purified by GPC.

Other solvents, active agents, promoters, and bases can be used. Examples of other solvents include dimethyl sulfoxide, ethers such as tetrahydrofuran or chlorinated solvents such as chloroform. Examples of other active agents are dicyclohexylcarbodiimide or thionyl chloride. An example of another promoter is N-hydroxysuccinimide. Examples of the base include pyrrolidinopyridine, dimethylaminopyridine, triethylamine or tributylamine.

Preparation of γ-alkyl glutamate (see FIG. 4)

There are 30 different γ-alkyl glutamate that may be suitable for the choice of alcoholic drug. For example, suspensions of glutamic acid, alcohols and concentrated hydrochloric acid can be prepared and heated for several hours. The γ-alkyl glutamate product can be precipitated in acetone, filtered off, dried and recrystallized with hot water.

γ-alkyl glutamate / C-terminal conjugate (see FIG. 4)

The peptide carrier can be dissolved in DMF under nitrogen and cooled to 0 ° C. The solution can then be treated with diisopropylcarbodiimide and hydroxybenzotriazole followed by the γ-alkyl glutamate bioactive agent. The reaction was then stirred at rt for 7 h and the urea byproduct was filtered off and the product precipitated in ether was purified by GPC or dialysis.

Preparation of γ-Alkyl Glutamate-NCA

γ-alkyl glutamate can be suspended in anhydrous THF to which triphosphene has been added and the mixture can be refluxed under a nitrogen atmosphere until the mixture is homogenized. The solution can be poured into heptane to precipitate the NCA product which can be filtered, dried and recrystallized with a suitable solvent.

Preparation of Poly [γ-Alkyl Glutamate]

γ-alkyl glutamate-NCA can be dissolved in dry DMF and a catalytic amount of primary amine can be added to this solution until it becomes viscous (typically overnight). The product can be isolated from the solution by pouring the solution into water and filtering. The product can be purified by GPC or dialysis.

Example  One

Preparation of a Capped Iodotyronine Composition Comprising a Copolymer of T ₃ and T ₄ Covalently Bonded to the N-Terminal of Polyglutamic Acid

The synthesis of glutamic acid is well known by a variety of reported methods. In this example, polyglutamic acid was synthesized by activation of the benzyl glutamic acid NCA (BnGlu-NCA) monomer. BnGlu-NCA was then polymerized and the benzyl group was removed with hydrogen bromide. When capping polyglutamic acid, it is important to liberate the hydrogen bromide composite N-terminal amino group without imparting undesired nucleophilicity to the free carboxylic acid. Reaction with sodium carbonate, sodium bicarbonate and sodium acetate resulted in a glutamic acid / T ₄ / T ₃ copolymer with reduced T ₄ and T ₃ incorporation and increased pKb. Sodium acetate is a preferred reagent because its pKb is between pKa of sodium bromide, polyglutamic acid and sodium salt. Reaction with basic alumina was maintained without T ₄ -NCA and T ₃ -NCA without discernible capping or self polymerization. The stability of T ₄ -NCA and T ₃ -NCA will affect the commercial preparation of glutamic acid / T ₄ / T ₃ copolymers. Sodium acetate can be replaced with sodium carbonate, sodium bicarbonate, sodium propionate, sodium butyrate, sodium pivalate, basic alumina, or any other weak base that can neutralize hydrogen bromide complexed with amino groups.

Synthesis of glutamic acid / T ₄ / T ₃ copolymers has been initiated by benzylglutamic acid, thyroxine and triiodotyronine. Each of these synthons reacted independently with tripphosgene in a suitable organic solvent. BnGlu-NCA was polymerized with sodium methoxylated initiator in tetrahydrofuran (THF). Polybenzylglutamic acid was deprotected with 15% hydrogen chloride in acetic acid. This product needs to be liberated from uncomplexed hydrogen chloride dissolved in DMF and treated with sodium acetate. Pre-made T ₄ -NCA and T ₃ -NCA were mixed and added to the solution. The reaction was then stirred until no more T ₄ -NCA and T ₃ -NCA were detected by thin layer chromatography (TLC). The final product was added to water and the precipitate was washed with water and dried in vacuo to yield a white amorphous powder.

Experiments with several weak bases have shown that several sodium salts of carboxylic acids act on the capping of polyglutamic acid. This reaction experiment was performed using sodium propionate, sodium butyrate and sodium pivalate instead of sodium acetate, and in all cases substantially the same results were obtained.

Preparation of Benzyl Glutamic Acid-NCA

Benzylglutamic acid (25 g) was suspended in 400 mL anhydrous ethyl acetate under nitrogen. The mixture was heated to reflux and 30 g of triphosgene was added equally in six portions. The reaction was refluxed for 3 hours until homogenized. The solution was cooled to rt, filtered and concentrated in vacuo. The white powder was recrystallized from high temperature anhydrous ethyl acetate to obtain 17.4 g (63%) of white powder.

Manufacture of T ₄ -NCA

In a round bottom flask equipped with a nitrogen inlet, 5 g of tyrosine was stirred with 25 mL of tetrahydrofuran (THF) and 1.3 g of triphosgene, and the mixture was refluxed for 4 hours until homogenized. The solution was cooled to rt and added dropwise to 200 mL of heptane with stirring. The crystals were filtered and dried in vacuo to give 4.72 g (91%) of an off-white powder.

Manufacture of T ₃ -NCA

In a round bottom flask equipped with a nitrogen inlet, 4.29 g of triiodothyronine was stirred with 20 mL of tetrahydrofuran (THF) and 1.45 g of triphosgene, and the mixture was refluxed for 4 hours until homogenized. The solution was cooled to rt and added dropwise to 200 mL of heptane with stirring. The liquid was decanted from the yellow gum, and the yellow gum was recrystallized from anhydrous ethyl acetate and hexane to give 2.5 g (56%) of a white powder and dried under high vacuum.

Preparation of Polybenzylglutamic Acid

Benzylglutamic acid (17.4 g) was dissolved in anhydrous tetrahydrofuran (THF) under nitrogen, and 238 mg of sodium methoxide was added in portions. The solution was stirred for 2 days and the viscosity increased significantly. The solution was poured into 1.5 L of petroleum ether with stirring. The petroleum ether was decanted off and 1 L of additional petroleum ether was added again. The mixture was stirred manually, the petroleum ether was decanted off and the process was repeated with 500 mL of petroleum ether. The white solid was air dried and then vacuum dried to give a white downy paper-like solid 14.7 (95%).

Preparation of Polyglutamic Acid

Acetic acid (10 mL) was stirred with 0 mL of 30 wt% hydrogen bromide (HBr) in acetic acid, with 1.96 polybenzylglutamic acid added by hand. The mixture was stirred for 1 day at room temperature and then added to 50 mL of ether. The white precipitate was filtered off, washed with 4 × 30 mL of ether, and dried under high vacuum to yield 1.11 g (97%) of white powder.

Preparation of Glutamic Acid / T ₄ / T ₃ Copolymers

Polyglutamic acid (375 mg) was dissolved in 3 mL of DMF. Sodium acetate (24 mg) was added followed by a blend of 105 mg T ₄ -NCA and 8 mg T ₃ -NCA. This solution was stirred for 2 days, TLC showed the absence of tyranine starting material. The solution was poured into 30 mL of water and cooled overnight at 10 ° C. The precipitate was filtered off, washed with water and dried under high vacuum to give 413 mg (85%) of a light beige powder. Proton NMR indicated that a copolymer of T ₃ and T ₄ was covalently bonded to the N-terminus of polyglutamic acid, which was virtually completely decomposed within 2 hours by the pronase enzyme system.

Example  2

Preparation of Peptide Polymers

Polyaspartic acid: Asp (OtBu) (13 mg, 0.07 mmol) and Asp (OtBu) -NCA (200 mg, 0.93 mmol) are dissolved in anhydrous DMF (5 ml) and the solution is stirred overnight at room temperature under argon atmosphere. I was. The next morning, 2.5 ml of the reaction mixture was transferred to a separate flask (Flask B). T ₄ -NCA (27 mg, 0.03 mmol) was added to the original flask (Flask A) and the two solutions were continued to stir for an additional 24 hours under argon. Water (30 ml) was added to each flask to precipitate the polymer. The resulting solids were collected by filtration and dried overnight under vacuum.

The dried Asp (OtBu) _n (flask B) and T ₄ -Asp (OtBu) _n (flask A) were then dissolved in 95% trifluoroacetic acid in water (3 ml) and stirred at room temperature for 2 hours. . After addition of ethyl ether (10 ml), the suspension was stored at 4 ° C. for 2 hours to precipitate the deprotected polymer. Each polymer was then collected by filtration and the solid was dried overnight under vacuum. This provided 48 ml of Asp _n (Flask B) and T ₄ -Asp _n (Flask A). MALDI indicated that T ₄ -Asp _n (Flask A) consisting of a mixture of polymers of various lengths was T ₄ -Asp _{3 -12} .

Polyserine and polythreonine were also prepared using this protocol. The serine reaction mixture contained N-methylmorpholine (1.1 equiv).

Amino acid derivatives polymer Isolation amount (mg) %yield Mass range Asp (OtBu) Asp (OtBu) n 48 84% Not measurable T4-Asp (OtBu) n 12 14% T4-Asp _{3 -12} Ser (OtBu) Ser (OtBu) n 73 101% ³ Ser _{7 -8} T4-Ser (OtBu) n 50 43% T4-Ser _{4 -9} Thr (OtBu) Thr (OtBu) n 29 20% Thr _{7 -8} T4-Thr (OtBu) n 66 24% T4-Thr _{1 -8}

% Yield was calculated based on the total amino acid content in the original reaction prior to splitting the reaction. Mass ranges were measured from MALDI. Yields greater than 100% may reflect an uneven distribution when salts are present or the reaction mixture is split.

HPLC and professionals xylanase experiment _{T 4 -Asp 3 -12, T 4} -Ser 4 -9, and T ₄ -Thr _{1 -8} in the sample indicates the T ₄ does not substantially present or not present at all, T is stable ₄ indicates free.

N-Carboxyhydride

N-carboxyhydrides (NCA's) of amino acids listed below were prepared using protocols similar to those reported for glutamic acid. In the final work, only minor changes are noted below.

amino acid Chemical shift in NCA α β γ Other (OtBu) Alanine 4.41 (q, 1 H) 1.57 (d, 3 H) Valine 4.20 (d, 1 H) 2.28-2.19 (m, 1 H) 1.08 (d, 3H) 1.02 (d, 3H) Serine (OtBu) 4.58 (m, 1 H) 3.62 (dd, 1H) 3.50 (dd, 1H) 1.10 (s, 9 H) Aspartic Acid (OtBu) 4.51 (dd, 1H) 2.93 (dd, 1H) 2.73 (dd, 1H) 1.44 (s, 9 H) Glutamic Acid (OtBu) 4.34 (dd, 1H) 2.28-2.20 (m, 1H) 2.09-1.99 (m, 1H) 2.45 (t, 2H) 1.44 (s, 9 H)

amino acid Isolation of the NCA Alanine 68% yield of precipitate in hexane Valine 89% yield of precipitate in hexane Serine (OtBu) 83% yield of suspension in isopropanol and precipitate in hexane Aspartic Acid (OtBu) 55% yield of suspension in isopropanol and precipitate in hexane Glutamic Acid (OtBu) 77% yield of suspension in isopropanol and precipitate in hexane

Example  3

Preparation of (Glu) _n -Sehalexin

Glu (OtBu) NCA (1.000 g, 4.4 mmol) and Sephalexin-HCl (0.106 g, 0.3 mmol) were dissolved in anhydrous DMF (5 ml). The reaction was then stirred at room temperature under argon. After 3 days, the solvent was removed by rotary evaporation under vacuum. The resulting solid was then placed under argon and then dissolved in 4N HCl in dioxane (2 ml) and then stirred at room temperature under an argon blanket. After 1 hour, dioxane and HCl were removed by rotary evaporation under vacuum. The solid was then suspended in methanol (2 ml) and dried once again by rotary evaporation to remove residual HCl and dioxane. This material was then resuspended in methanol (2 ml) and precipitated by addition of water (20 ml). The aqueous suspension was then lowered at 4 ° C. for 4 hours and the solids were isolated by centrifugation. The pelletized material was then dried overnight under vacuum. As measured by MALDI, this process provided a mixture of (Glu) _n and (Glu) _n -cepthalexin (464 mg). MALDI represents a mixture of polymers (Glu) _7-13 and (Glu) _5-14 -cepthalexin. There may be chains of other lengths, but they were not clearly visible in the MALDI spectra. Reversed phase HPLC (265 nm detection, C18 column, 16% MeOH / 4% THF / 80% water mobile phase) showed no free secephalins in the isolated material. By HPLC "water" actually refers to an aqueous buffer of 0.1% heptanesulfonic acid and 1.5% triethylamine.

Example  4

Naltrexone derivatives:

3-Methyl-naltrexone: Naltrexone (6.0 g, 16.5 mmol) was dissolved in 100 ml of distilled water. The solution was triturated with 1N NaOH to a final pH of 11.8. During grinding, neutral naltrexone precipitated out of solution and then dissolved back into solution. When pH 11.8 was reached, the solvent was removed by rotary-evaporation under vacuum and the resulting solid was stored overnight under vacuum at room temperature. The solid was then suspended / dissolved in anhydrous tetrahydrofuran (200 ml) and stirred at room temperature under argon. A solution of iodomethane (2.1 mg, 33 mmol) in 50 ml of tetrahydrofuran was added dropwise over 30 minutes. Thereafter, the reaction was further stirred at room temperature under argon for 3 hours. The solvent was then removed by spin-evaporation under reduced pressure. The remaining solid was dissolved in 40 ml of CHCl ₃ and the organic solution was washed with 30 ml of saturated NaCl, 3 × 30 ml of 1N NaOH, and finally twice more with 30 ml of saturated aqueous NaCl. The organic solution was collected and dried over sodium sulfate. The solvent was removed by rotation-evaporation and dried under vacuum overnight to give pure 3-methylnaltrexone (5.6 g, 15.8 mmol, 96% yield) as a brown residue, whose composition was determined by TLC and ¹ H-NMR. Features used to identify compounds by comparison with the spectrum of naltrexone: ¹ H-NMR (360 MHz, CDCl ₃ ) δ 6.677 (d, 1H, naltrexone aromatic), 6.591 (d, 1H, naltrexone aromatic), 3.874 ( s, 3H, methoxy group), 0.6-0.5 ppm (m, 2H, naltrexone cyclopropyl) and 0.2-0.1 ppm (m, 2H, naltrexone cyclopropyl).

Boc-Glu (Nal) -OtBu: solid Boc-Glu-OtBu (0.96 g, 3.18 mmol), naltrexone (1.00 g, 2.65 mmol) and PyBrop (1.73 g, 3.71 mmol) are dissolved in 5 ml of anhydrous DMF and argon Stir at room temperature. Anhydrous N-methylmorpholine (1.08 ml, 9.81 mmol) was added and the reaction was continued stirring at room temperature under argon. After 2 days additional Boc-Glu-OtBu (0.096 g, 0.32 mmol), PyBrop (0.173 g, 0.37 mmol) and N-methylmorpholine (0.10 ml, 0.981 mmol) were added. After two more days, the solvent was removed under high vacuum by rotation-evaporation. The residue obtained was then dissolved in CHCl ₃ and the resulting organic solution was extracted with 2 × 20 ml of saturated NaCl, 3 × 20 ml of 10% Na ₂ CO ₃ and finally washed with 20 ml of saturated aqueous NaCl. The organic solution was collected and dried over sodium sulfate and then adsorbed onto silica. Pure naltrexone (0.486 g, 0.78 mmol, 29%) conjugated with amino acid was then isolated by flash chromatography (gradient of 0-1.5% CH ₃ OH in CHCl ₃ ). The purity of the isolated material was determined by TLC (6: 1 CH ₃ OH / CHCl ₃ ) and the presence of both amino acid residues and naltrexone was confirmed by ¹ H-NMR. Marked protons: ¹ H-NMR (360 MHz, CDCl ₃ ) δ 6.81 (d, 1H, naltrexone aromatic), 6.63 (d, 1H, naltrexone aromatic), 4.3-4.2 (m, 1H, glutamic acid α- Protons), 1.7-1.3 (pair of bs, 18H, Boc and OtBu groups), 0.6-0.4 ppm (m, 2H, naltrexone cyclopropyl) and 0.2-0.0 ppm (m, 2H, naltrexone cyclopropyl).

Boc-Asp (Nal) -OtBu: Boc-Asp (Nal) -OtBu was obtained in 41% isolation yield using a similar protocol. Marked Protons: ¹ H-NMR (360 MHz, CDCl ₃ ): δ 6.84 (d, 1H, naltrexone aromatic), 6.66 (d, 1H, naltrexone aromatic), 4.6-4.5 (m, 1H, aspartic acid α-proton) , 1.6-1.3 (pair of bs, 18H, Boc and OtBu groups), 0.7-0.5 ppm (m, 2H, naltrexone cyclopropyl) and 0.4-0.1 ppm (m, 2H, naltrexone cyclopropyl).

NMR Characteristics:

Naltrexone has a complex NMR spectrum, but some major protons have unique chemical shifts and are specific for naltrexone.

Example  5

Poly-Glu (Acyclovir)

To a solution of poly-glu ₁₅ (0.600 g, 0.310 mmol) in DMF (25 ml) was added EDCI (2.07 g, 10.8 mmol). The resulting mixture was stirred at ambient temperature for 1 hour. Then N-methyl morpholine (0.51 ml, 4.7 mmol) was added followed by a mixture of acyclovir (1.74 g, 7.75 mmol), DMF (25 ml) and N-methyl morpholine (0.85 ml). The reaction mixture was stirred at ambient temperature for 4 days. Then water (50 ml) was added and all solvent was removed. Water (100 ml) was added to the dried mixture and a precipitate of unreacted acyclovir was formed. The solid was centrifuged and the supernatant was purified by ultrafiltration (YM1 membrane). About 300 ml of water were passed through the membrane. NMR showed unexpected attachment of alkyl-urea side chain impurities. Poly-glu (acyclovir) (0.970 g) was obtained as a light yellow solid: ¹ H NMR (D ₂ O) δ 1.11 (br m, 4H, urea), 2.01 (br m, 2H, Glu-βH), 2.39 ( br m, 2H, Glu-γH), 2.72 (br m, 2H, urea), 3.32 (br m, 6H, acyclovir CH ₂ and urea), 3.83 (br m, 3H, urea), 4.38 (br d, 3H , Glu-α H), 5.47 (br s, 2H, Acyclovir 1 ′ CH ₂ ), 7.94 (br s, 1H, Acyclovir 8 CH).

Example  6

Poly-Glu (Fexofenadine)

EDCI (0.035 g, 0.18 mmol) was added to a solution of poly-Glu ₁₅ (0.078 g, 0.040 mmol) in DMF (5 mL). After stirring for 30 minutes, N-methyl morpholine (0.03 mL, 0.24 mmol) was added. After stirring for 10 minutes, a solution of fexofenadine (0.100 g, 0.20 mmol), N-methyl morpholine (0.07 mL, 0.60 mmol) and DMF (5 mL) was added via syringe. After stirring for 3 days at room temperature, the sample was dissolved in water (25 mL). A solid precipitate formed that was drug-conjugated and free of fexofenadine. Water was acidified and all solids dissolved. Purification using ultrafiltration (YM1 after YM3) and size exclusion chromatography with Sephadex-25 at pH 7 yielded poly-Glu (Fexofenadine) (0.010 g) as a white solid. ¹ H NMR (D ₂ O) δ 1.37 (s, 8H, fexofenadine CH ₂ and CH ₃ ), 1.58 (br m, 5H, fexofenadine CH and CH ₂ ), 1.99 (br m, 24H, Glu-βH), 2.31 (br m, 24H, Glu-γH), 2.70 (br m, 10H, fexofenadine CH and CH ₂ ), 4.14 (br m, 26H, Glu-αH), 7.25 (br m, 14H, fexofenadine aromatic H)

H).

Example  7

Poly-Glu (Zalcitabine)

To a solution of poly-Glu ₁₅ (0.123 g, 0.060 mmol) in DMF (8 mL) was added EDCI (0.403 g, 2.10 mmol). After 30 minutes, N-methyl morpholine (0.13 mL, 1.2 mmol) was added. After 35 minutes, a solution of zalcitabine (0.200 g, 0.95 mmol), N-methyl morpholine (0.10 mL, 0.9 mmol) and DMF (2 mL) was added via syringe. The resulting mixture was stirred at room temperature for 48 hours. Solvent was removed and the residue was dissolved in water (15 mL). Ultrafiltration (YM1 after YM3) and size exclusion chromatography with Sephadex-25 at pH 7 yielded poly-Glu (Jalcitabine) (0.083 g) as a light yellow solid. ¹ H NMR (DMSO-d ₆ w / D ₂ O) δ 1.14 (br m, 20H, urea), 1.90 (br m, 30H in zalcitabine, Glu-βH, Glu-γH and CH ₂ ), 2.66 ( br m, 4H, urea), 3.24 (br m, 36H, urea in zalcitabine, CH and CH ₂ ), 4.29 (br m, 8H, Glu-αH), 5.87 (br s, 1H, zalcitabine 1'CH ), 7.18 (br s, 1.19 H, zalcitabine NH ₂ ), 8.52 (br s, 1H, zalcitabine 6 CH).

Example  8

Poly-Glu (stavudine)

Prepared similar to poly-Glu (Zalcitabine). Purification using ultrafiltration (YM1) gave poly-Glu (stavudine) (0.089 g) as a white solid. ¹ H NMR (D ₂ O) δ 1.87 (s, 3H, stavudine 5 CH ₃ ), 2.06 (br m, 38H, Glu-βH and Glu-γH), 2.49 (br m, 12H, Glu-γH) , 3.75 (br m, 12H, urea and stavudine 5 'CH ₂ ), 3.96 (br m, 12H, urea), 4.45 (br d, 13H, Glu-αH), 5.98 (d, 1H, stavudine 1' CH), 6.48 (d, 1H, stavudine 3 ′ CH), 6.96 (d, 1H, stavudine 2 ′ CH), 7.63 (s, 1H, stavudine 6 CH).

Example  9

Poly-Glu (Metronidazole)

Prepared similar to poly-Glu (Zalcitabine). Purification using ultrafiltration (YM1) afforded poly-Glu (metronidazole) (0.326 g) as a yellow solid. ¹ H NMR (DMSO-d ₆ ) δ 1.18 (br d, 13H, urea), 1.93 (br s, 17H, Glu-βH and Glu-γH), 2.71 (br s, 16H, urea), 4.01 (br m, 18H, Glu-αH and metronidazole CH ₂ ), 4.58 (br s, 2H, metronidazole CH ₂ ), 8.05 (br s, 1H, metronidazole 2 CH).

Example  10

Methyl Naltrexone-Glucose Ketal Conjugate

To a solution of methyl naltrexone (0.200 g, 0.56 mmol) in dioxane (20 ml), D-α-glucose (2.02 g, 11.2 mmol), trifluoromethanesulfonic acid (0.05 ml, 0.62 mmol) and CuS0 ₄ (1. OO g) was added. The reaction mixture was stirred at room temperature for 4 days. The reaction was then filtered, neutralized with NaHCO ₃ (saturated) and filtered again. Dioxane and water were removed and the residue was taken up in CHCl ₃ and extracted with water (3 × 100 ml). The organic layer was dried over MgSO ₄ and the solvent was removed under reduced pressure. The crude product was purified on silica gel (0-10% MeOH in CHCl ₃ ) to give the ketal conjugate (O.O10 g) as a 1: 1 mixture with free methyl naltrexone: ¹ H NMR (CDCl ₃ ) δ 0.14 ( br s, 4H, naltrexone cyclopropyl), 0.53 (br m, 4H, naltrexone cyclopropyl), 0.90 (m, 2H, naltrexone cyclopropyl), 1.48 (m, 6H, naltrexone), 2.19-2.78 (m, 12H, Naltrexone), 3.03 (m, 2H, naltrexone), 3.75 (q, 2H, glucose), 3.87 (m, 8H, naltrexone CH ₃ and glucose), 3.97 (q, 2H, glucose), 4.14 (q, 1H.glucose ), 4.33 (t, 1H, glucose), 4.66 (s, 1H, naltrexone), 6.65 (m, 4H, naltrexone).

Example  11

2-amino-pentanedioic acid 5- (4-acetylamino-phenyl) ester or Glu (acetaminophen)

To a solution of Boc-Glu (OSuc) -OtBu (0.500 g, 1.25 mmol) and acetaminophen (0.944 g, 6.25 mmol) in THF (15 ml) was added N-methyl morpholine (1.40 ml, 12.5 mmol). The reaction was heated to reflux and stirred at reflux overnight. The solvent was then removed and the crude compound was purified on silica gel (50-75% ethyl acetate in hexanes) to give Boc-Glu (acetaminophen) -OtBu (0.432 g, 0.900 mmol, 72%): ¹ H NMR (CDCl ₃ ) δ 1.43 (d, 18H, t-Bu), 1.97 (m, 1H, Glu-βH), 2.12 (s, 3H, acetaminophen CH ₃ ), 2.25 (m, 1H, Glu-βH), 2.60 (m, 2H, Glu-γH), 4.25 (m, 1H, Glu-αH), 7.04 (d, 2H, acetaminophen aromatic), 7.48 (d, 2H, acetaminophen aromatic).

A solution of Boc-Glu (acetaminophen) -OtBu (0.097 g, 0.20 mmol) in 4 N HCl in dioxane (10 ml) was stirred at room temperature for 2 hours. Removal of solvent gave glu (acetaminophen) (0.90 g) as HCl salt: ¹ H NMR (D ₂ 0) δ 2.19 (s, 3H, acetaminophen CH ₃ ), 2.41 (m, 2H, Glu-βH ), 2.97 (t, 2H, Glu-γH), 4.18 (t, 1H, Glu-αH), 7.19 (d, 2H, acetaminophen aromatic), 7.51 (d, 2H, acetaminophen aromatic); ¹³ C NMR (DMSO) δ 23.80, 29.25, 51.00, 66.24, 119.68, 121.69, 137.00, 145.35, 168.23, 170.42, 170.79.

3- (2,5-Dioxo-oxazolidin-4-yl) -propionic acid 4-acetylaminophenyl ester or Glu (acetaminophen) NCA

Triphosgen (1.02 g, 3.43 mmol) was added to a mixture of 2-amino-pentanedioic acid 5- (4-acetylamino-phenyl) ester (1.54 g, 4.29 mmol) in THF (40 ml). The resulting solution was stirred at reflux for 3 hours. During the reaction, the product precipitated and was filtered to give NCA of glu (acetaminophen) as off-white solid (1.02 g, 2.64 mmol, 62%): ¹ H NMR (DMSO-d ₆ ) δ 2.01 (s, 3H, Acetaminophen CH ₃ ), 2.15 (m, 2H, Glu-βH), 2.81 (m, 2H, Glu-γH), 3.76 (t, 1H, Glu-αH), 7.06 (d, 2H, acetaminophen aromatic), 7.63 (d, 2H, acetaminophen aromatic), 8.57 (br s, 1H, amide), 10.19 (s, 1H, amide); ¹³ C NMR (DMSO) δ 23.81, 29.25, 52.13, 54.62, 119.66, 121.71, 136.98, 145.35, 167.44, 168.19, 170.46, 170.77.

Example  12

Glu (dipyrimadol)

In a solution of dipyrimadol (0.500 g, 0.990 mmol) and Boc-Glu (OSuc) -OtBu (3.96 g, 9.91 mmol) in THF (35 ml), DMAP (0.072 g, 0.60 mmol) and N-methyl morpholine ( 0.22 ml, 1.98 mmol) was added. The solution was then refluxed for 48 hours. The solvent was then removed and the crude product was purified on silica gel (25-50% ethyl acetate in hexanes). Two main products were isolated, one of which was R = 2-3 (0.57 g), the other was R = 3-4 (2.80 g) and a light yellow oil: [R = 2-3, ¹ H NMR (CDCl ₃ ) δ 1.41 (s, 42H, t-Bu), 1.64 (br s, 5H, dipyrimadol), 1.85 (m, 2H, Glu-βH), 2.07 (m, 2H, Glu- βH), 2.37 (m, 4H, Glu-γH), 3.60-4.24 (m, 12H, Glu-αH and dipyrimadol)]; [Similar to above except for 1.44 (s, 56H, t-Bu) when R = 3-4].

A solution of Boc-Glu (dipyrimadol) -OtBu (R = 2-3, 0.57 g) and 4 N HCl in dioxane (20 ml) was stirred at room temperature for 2.5 hours. The solvent was removed and the product (0.280 g) was a light yellow solid: ¹ H NMR (DMSO-d ₆ ) δ 1.65 (br m, 4H, Glu-βH and dipyrimadol), 2.04 (br m, 2H, Glu -βH), 2.40 (br m, 4H, Glu-γH), 3.75 (br m, 8H, dipyridol), 3.91 (br m, 2H, Glu-αH), 8.55 (br m, 2H, amide H) .

Example  13

Glu (AZT)

DMAP (0.137 g, 1.13 mmol) and N-methyl morpholine in a solution of dozibudine (1.OO g, 3.75 mmol) and Boc-Glu (OSuc) -OtBu (3.00 g, 7.49 mmol) in dioxane (75 ml) (0.82 ml, 7.49 mmol) was added. The solution was heated to reflux for 6 hours and heated at 70 ° C. for 12 hours. The solvent was then removed and the crude product was purified on silica gel (100% CHCl ₃ ) to give Boc-Glu (AZT) -OtBu (1.09 g, 1.91 mmol, 51%) as a yellow foam: ¹ H NMR (CDCL ₃ ) δ 1.40 (d, 32H, t-Bu), 1.86 (s, 3H, AZT CH ₃ ), 2.11 (m, 2H, Glu-βH), 2.38 (m, 4H, Glu-γH and AZT 2'CH ₂ ), 4.00-4.31 (m, 4H, AZT 4'CH, 5'CH ₂ and Glu-αH), 5.21 (d, 1H, AZT 3'CH), 6.01 (t, 1H, AZT 1'CH), 7.16 (s, 1H, AZT 6CH).

A solution of Boc-Glu (AZT) -OtBu (1.09 g, 1.91 mmol) in 4 N HCl in dioxane (20 ml) was stirred for 4 hours and the solvent was removed. The product Glu (AZT) (0.89 g, 1.99 mmol, quantitative) was obtained as a yellow glass: ¹ H NMR (D ₂ 0) δ 1.89 (s. 3H, AZT CH ₃ ), 2.21 (m, 4H, Glu − βH and AZT 2'CH ₂ ), 2.58 (m, 2H, Glu-γH), 3.70 (t, 1H, Glu-αH), 4.05-4.41 (m, 4H, AZT 4'CH, 3'CH and 5 ' CH ₂ ), 6.18 (t, 1H, AZT 1′CH), 7.51 (s, 1H, AZT 6CH).

Example  14

Threonine NCA

Triphosgene (0.677 g, 2.28 mmol) was added to a mixture of Thr-OtBu (0.500 g, 2.85 mmol) in THF (25 ml). The resulting solution was stirred at reflux for 3 hours. The solution was evaporated to dryness to give Thr-NCA as a white solid (0.500 g, 2.48 mmol, 87%). Thr-NCA was used without further characterization.

Example  15

Preparation of DRUG-GLU Conjugates as Starting Synthetic Comparators for Polymerization

As non-primary amine drug candidates, the formation of Drug-poly-Glu conjugates can prove to be problematic. To overcome this difficulty, the following scheme was used where the drug was first conjugated with Glu and then this synthetic equivalent was used in the disclosed coupling. The protocol was successfully applied to sertraline and metoclopramide.

Protocol for Coupling Boc-Glu (OtBu) -OH with Sertraline

1. Boc-Glu (OtBu) -OH (0.44 g, 1.46 mmol) and PyBOP (0.84 g, 1.60 mmol) were stirred and dissolved in anhydrous DMF (15 mL).

2. DIEA (0.31 mL, 1.75 mmol) was added and the amino acid derivative was activated for 15 minutes.

3. Sertraline hydrochloride (0.50 g, 1.46 mmol) was added to the stirring mixture, followed by additional 0.31 mL of DIEA.

4. The mixture was stirred for 16 hours.

5. The solution was removed to give a brown oil.

6. The oil was dissolved in EtOAc (100 mL) and the resulting solution was washed with 10% HCl (3 × 30 mL), saturated NaHCO ₃ , 4M NaHS0 ₄ and brine (2 × 30 mL, each).

7. The solution was dried over MgSO ₄ , filtered, and the solvent was removed with a rotary evaporator under reduced pressure to give a light brown oil.

8. The oil was dried on a vacuum manifold and the product was purified by column chromatography on silica gel using EtOAc / hexane 1: 5 to 1: 4 solvent system.

9. The product fractions were pooled and the solvent was removed again by rotary evaporator to give 0.85 g (99%) of the final product, sertraline-NH-C (O) -Glu-NH 3+.

10. The formulation was dried on a vacuum manifold.

Example  16

Synthesis of Poly-lysine-Ibuprofen

I. Preparation of Ibuprofen-O-succinimide (RI-172) (Grafe & Hoffman, Pharmazie 55: 286-292, 2000)

To a stirring solution of ibuprofen (2.06 g, 10 mmol) in 5 mL of dioxane at room temperature was added a solution of dicyclohexylcarbodiimide (DCC, 2.27 g, 11 mmol) in 25 mL of dioxane. After 10 minutes, a solution of N-hydroxysuccinimide (NHS, 1.16 g, 10 mmol) in 15 mL of dioxane was added. The reaction mixture was stirred at rt for 5 h and then filtered through a calcined glass funnel to remove dicyclohexylurea (DCU). After rotary evaporation, the product was crystallized in methylene chloride / hexanes to give 2.36 g (78%) of a colorless solid. ¹ H-NMR (dmso-d6): δ0.86 (d, 6, CH ₃ ), 1.49 (d, 3, α-CH ₃ ), 1.81 (m, 1, CH), 2.43 (d, 2, CH ₂ ), 3.33 (m, 4, CH ₂ CH ₂ ), 4.22 (q, 1, CH), 7.16 (d, 2, ArH), 7.28 (d, s, ArH).

II. Conjugation of Poly-lysine with Ibuprofen-O-Succinimide (RI-197)

Poly-lysine-HBr (Sigma, 100 mg, 34.5 nmol) was dissolved in 1 mL of water made to pH 8 using sodium bicarbonate and stirred at room temperature. To this solution was added a solution of ibuprofen-O-succinimide (116 mg, 380 nmol) in 2 mL of dioxane. After stirring overnight, dioxane was removed by rotary evaporation and diluted with 10 mL of sodium bicarbonate in water at pH 8. The precipitated product was filtered through a calcined glass funnel and washed with 3 × 10 mL of water and 4 × 10 mL of diethyl ether. After overnight drying by high vacuum, 105 mg (62%) of solid product were scraped off. ¹ H-NMR (dmso-d6): δ 0.85 (br s, 6, CH ₃ ), 1.27 (br s, 3, α-CH ₃ ), 1.40-1.79 (m, 5, minor, CH, γ of lysine And δ CH ₂ CH ₂ ), 2.31 (d, 2, βCH ₂ ), 2.41-2.52, under dmso (m, 2, βCH ₂ ), 2.73-3.01 (m, 2, εCH ₂ ), 3.51-3.85 (m , 1 bipart CH), 4.01-4.43 (m, 1, αCH), 7.14 (d, 2, ArH), 7.6 (d, 2, ArH), 7.90-8.06 (m, 2, NH).

Example  17

Synthesis summary of [lysine] _xx , [gemfibrozil or naproxen] or [Glu] _xx L-DOPA

[Glu] -L- _{15-dihydroxy-phenylalanine} or [Glu] Synthesis of ₁₅ -L-DOPA

L-DOPA (0.050 g, 254 μmol) and GluNCA (0.666 g, 3.85 mmol) were dissolved in 6 mL of DMF. After overnight stirring under argon, thin layer chromatography, the reaction product _{(9: 1 H 2 0:} HOAc) to point the reaction is a more polar estimated to be a specific free drug (R _f = 0.70) and a polymer (R _f = 0.27) Appearance was examined. The reaction was quenched by addition of 12 mL of H ₂ O. The pH was adjusted to pH 1-2 with 1N HCl. The solvent was removed on a rotary evaporator and the viscous residue was dried under vacuum. The resulting syrup was transferred to a new container containing H ₂ O and lyophilized. The resulting crystals were off-white to light brown. Yield: 0.470 g, 62%. ¹ H NMR showed a pyroglutamic acid mixture: the material was suspended in H ₂ O, ultrafiltration (Millipore preparation, regenerated cellulose, YM1, NMWL = 1,000) and the retentate was dried under vacuum. Yield: 0.298 g. ¹ H NMR (500 MHz, DMSO) provides Glu: L-DOPA, 6.6 (L-DOPA aromatic), 6.4 (L-DOPA aromatic), 4.1 (Glu, α) 1.85 (Glu, β) with a relative ratio of 30: 1. , 2.25 (Glu, γ, L-DOPA), 2.3 (L-DOPA, benzyl), 12.4-11.5 (Glu, CO ₂ H), 8.0 (Glu, amide).

Synthesis of [Glu] ₁₀ -L-DOPA

Same as in the synthesis of [Glu] ₁₅ -L-DOPA, except that 0.439 g of GluNCA was used. The final yield of the purified material was 0.007 g. ¹ H NMR (500 MHz, DMSO) showed 8: 1 Glu: L-DOPA.

Synthesis of Naproxen-Succinimide

N-hydroxysuccinimide (1.16 g, 10 mmol) dissolved in 15 mL of dioxane in naproxen (2.303 g, 10 mmol) in 5 mL of dioxane and dicyclohexylcarbodiimide dissolved in 25 mL of dioxane ( 2.27 g, 11 mmol) was added. The reaction was stirred overnight and insoluble dicyclohexylurea was filtered off. The solvent was removed on a rotary evaporator and the residue was dissolved in 30 to 40 mL of CH ₂ Cl ₂ . About 10 mL of hexane was added and the mixture was cooled at 4 ° C for 2 h. Hexane was further added dropwise until small planar crystals began to form, the activated esters were collected, washed with hexanes and dried under vacuum (2.30 g, 70.0%). ¹ H NMR (500 MHz, DMSO) 1.70 (d, 3H, CH ₃ ), 2.9 (s, 4H, succinimide), 3.91 (s, 3H, OCH ₃ ), 4.18 (q, 1H, methine) 7.75- 7.12 (m, 6H, aromatic).

Synthesis of Polylysine-Naproxen

Succinimide (0.124 g, 379 mmol) - [Lys] 14 · 14 · HBr naproxen in dioxane 2 ㎖ a (0.100 g, 35 mmol) in H ₂ O 1 ㎖ (containing _{10 mg / ㎖ Na 2 C0 3} ) Was added. After stirring overnight, a precipitate formed. 30 to 40 ml of H ₂ 0 (containing 10 mg / ml Na ₂ CO ₃ ) was added to precipitate further, isolated by filtration and washed with 50 ml of Et ₂ 0. The white fine powder was dried (0.095 g, 53%): ¹ H NMR (500 MHz, DMSO) 8.1 (m, 1H, lysine; amide), 7.8-7.0 (m, 6H, aromatic), 4.4-4.1 (m , 2H, α methine), 3.3 (s, 3H, OCH ₃ ), 2.8 (m, 2H, ε), 1.7-1.0 (m, 9H, β, γ, δ, CH ₃ ).

Synthesis of gemfibrozil-succinimide

Gemfibrozil (GEM) (5.0 g, 20.0 mmol) in 30 ml dioxane to N-hydroxysuccinimide (2.3 g, 20.0 mmol) in 20 ml dioxane and dicyclohexylcarbodiimide in 50 ml dioxane (4.5 g, 22.0 mmol) was added. The reaction was stirred overnight and insoluble dicyclohexylurea was filtered off. The solvent was removed by rotary evaporator and the residue was dissolved in 15-20 mL CH ₂ Cl ₂ . Hexane was added dropwise until crystals formed, and the mixture was cooled at 4 ° C overnight. An additional 3 ml of n-hexane was added and the mixture was cooled at -20 ° C overnight. The activated ester formed into small planar crystals which were collected, washed with hexanes and dried under vacuum (5.8 g, 80%): ¹ H NMR (500 MHz, DMSO) 1.2, 1.3 (s, 6H, CH ₃ ), 1.8-1.5 (m, 6H, GEM CH ₂ ), 2.3-2.1 (s, 6H, aromatic CH ₃ ) 2.85-2.7 (d, 4H, succinimide CH ₂ ), 7.0-6.6 (m, 3H , Aromatic).

Synthesis of Polylysine-Gemfibrozil

_{H 2 0 1 ㎖ (10 mg} / ㎖ Na 2 C0 3 content) of _{[Lys] 11 · 11 · HBr} (0.100 g, 43.5 μmol) in dioxane 2 ㎖ gemfibrozil in-succinimide (0.094 g, 261.1 μmol) was added. After stirring overnight, a precipitate formed. 30 ml of H ₂ 0 (containing 10 mg / ml Na ₂ CO ₃ ) was further precipitated, isolated and washed with 50 ml of Et ₂ 0. The white fine powder was dried (0.019 g, 1%): ¹ H NMR (500 MHz, DMSO) 1.5-1.0 (m, 12H, β, γ, δ, CH ₃ ), 1.85-1.5 (m, 4H, CH ₂ ), 2.3, 2.1 (s, 6H, aromatic CH ₃ ), 3.35 (s, 2H, ε), 3.85 (s, 2H, OCH ₂ ), 4.05 (s, 1H, α), 5.6 (d, 1H, Carbamate), 7.0-6.7 (m, 3H, aromatic), 8.0 (d, 1H, amide).

Example  18

All reagents were used as tolerated. ¹ H NMR was performed on a Bruker 300 MHz (300) or JEOL 500 MHz (500) NMR spectrometer using tetramethylsilane as internal standard. Thin layer chromatography was performed using a plate previously coated with silica gel 60 F ₂₅₄ . Flash chromatography was performed using silica gel 60 (230-400 mesh).

Manufacture of PolyArg

Method 1

To H-Arg (Z) ₂ -OH (0.300 g, 0.68 mmol) in 3.0 ml of dry DMSO was added diphenylphosphoryl azide (219 μl, 1.02 mmol) and triethylamine (236 μl, 1.69 mmol).

After the reaction was stirred under argon for 48 hours, the solution was poured into 100 ml of H ₂ O. The resulting heterogeneous solution was centrifuged to isolate a white precipitate, which was washed three times with 100 ml of H ₂ O, three times with 100 ml of CH ₂ OH and 100 ml of Et ₂ O, followed by vacuum drying to give an off-white solid. 172 mg were obtained: ¹ H NMR (500 MHz, DMSO) 7.31 (m, 10H), 5.21 (m, 1H, benzyl), 5.01 (m, 1H, benzyl), 3.83 (m, 1H, α), 3.34 (m, 2H, δ), 1.54 (m, 4H, β, γ).

This material was dissolved in 1.5 ml of dry anisole and stirred with 0.3 ml of methanesulfonic anhydride for 3 hours, then additional 0.3 ml of methanesulfonic anhydride was added and the solution was stirred for 1 hour. The reaction mixture was poured into 6 ml of Et ₂ O and refrigerated for 15 minutes. The heterogeneous dibasic mixture was concentrated to 0.5 ml by rotary evaporation. An additional 8 ml of Et ₂ O was added three times, the dibasic mixture was centrifuged, the supernatant was removed and a yellow gum remained. This residue was washed twice with 6 ml of acetone, centrifuged and the supernatant was discarded to leave an off white residue. The residue was dissolved in 0.3 ml of H ₂ O and shaken with Amberlite IRA-400. The resin was filtered off and washed with 3 ml of H ₂ O. The combined eluate and wash were dried in vacuo to give 0.063 g (90% yield) of a yellow film: ¹ H NMR (500 MHz, D ₂ 0) 4.37 (m, 1H, α), 3.22 (m, 2H, δ), 1.94-1.66 (m, 4H, β, γ); MALDI-MS showed varying degrees of polymerization with 6 to 14 residues.

Method 2

Diphenylphosphoryl azide (219 μl, 1.02 in Boc-Arg (Z) ₂ -OH (0.025 g, 0.05 mmol) and H-Arg (Z) ₂ -OH (0.280 g, 0.63 mmol) in 3.0 ml of dry DMSO. mmol) and triethylamine (236 μl, 1.69 mmol) were added. The reaction was stirred for 48 hours and then poured into 100 ml of H ₂ O. The heterogeneous solution was centrifuged and the precipitate was washed three times with 100 ml of H ₂ O, three times with 100 ml of CH ₃ 0H and 100 ml of Et ₂ O, followed by vacuum drying to give 132 mg of solid: ¹ H NMR (500 MHz, DMSO) 7.31 (m, 10H), 5.21 (m, 1H, benzyl), 5.01 (m, 1H, benzyl), 3.83 (m, 1H, α), 3.34 (m, 2H, δ) , 1.54 (m, 4H, β, γ).

The protected polymer was dissolved in 1.5 ml of dry anisole and stirred with 1.3 ml of methanesulfonic anhydride for 4 hours. The solution was concentrated to 0.5 ml by rotary evaporation. Et ₂ O (8 ml) was added, the dibasic system was centrifuged and the supernatant was discarded. 10 ml of acetone were added three times, the solution was centrifuged and the supernatant was discarded. The pellet was vacuum dried overnight, then dissolved in 0.3 ml of H ₂ O and shaken with Amberlite IRA-400. The resin was filtered off and washed with 3 ml of H ₂ O. The combined eluate and wash were dried in vacuo to afford 0.019 g (24% yield) of a yellow film; ¹ H NMR (500 MHz, D ₂ 0) 4.37 (m, 1H, α), 3.22 (m, 2H, δ), 1.94-1.66 (m, 4H, β, γ); MALDI-MS showed varying degrees of polymerization with 5 to 7 residues.

Preparation of T4 Conjugates

T4 conjugated with an amino acid polymer was prepared by coupling a commercially available amino acid homopolymer with (protected) T4 or by polymerization of the corresponding N-carboxyhydride amino acid with the T4 residue.

Conjugate of homopolymer preformed with T4

Dicyclohexylcarbodiimide (0.004 g, 18 μmol) was added to N-TeocT4 (0.017 g, 17 μmol) in 1 ml of dry DMF. After stirring for 30 minutes, diethyl-4-aminopyridine (0.004 g, 36 μmol) and Gly ₁₈ (0.017 g, 17 μmol) were added and the reaction stirred overnight. The cloudy solution was poured into 20 ml of H ₂ O and extracted twice with 10 ml of CH ₂ Cl ₂ . The aqueous component was acidified to pH 3 with 1 N HCl and cooled to 4 ° C. This material was isolated by centrifugation and the pellet was washed three times with 8 ml of H ₂ O. The pellet was dried in vacuo to give dicyclohexylurea and N-TeocT4-Gly ₁₈ : ¹ H NMR (500 DMSO) 7.8 (T4 aromatic), 7.1 (T4 aromatic), 4.1 (α).

2 ml of trifluoroacetic acid was added to the non-pure protected polymer. The reaction was stirred for 2 hours and the solvent was removed by rotary evaporation. The residue was dissolved in 1 ml of DMF and the insoluble material was filtered off. DMF was removed by rotary evaporation and vacuum dried to afford a white material (0.012 g, 40%): ¹ H NMR (500 DMSO) 7.75 (T4 aromatic), 7.08 (T4 aromatic), 4.11 (bs, α ).

Preparation of Amino Acids NCA

Triphosgene (0.8 equiv) was added to L-amino acid (1.5 g) in 100 ml of dry THF. The reaction vessel equipped with the reflux condenser and NaOH trap was heated to reflux for 3 hours. The solvent was removed by rotary evaporation and the residue was washed with hexane to afford amino acid NCA as a white residue.

LeuNCA: ¹ H NMR (500 CDCl ₃ ) 6.65 (s, 1H, NH), 4.33 (dd, 1H, α), 1.82 (m, 2H, β), 1.68 (m, 1H, γ), 0.98 (dd, 6H, δ).

PheNCA: ¹ H NMR (500 CDCl ₃ ) 7.36-7.18 (m, 5H), 5.84 (s, 1H, NH), 4.53 (dd, 1H), 3.28 (dd, 1H, α), 2.98 (dd, 1H, β).

Trp (Boc) NCA:: ¹ H NMR (500 CDCl ₃ ) 8.14 (d, 1H), 7.49 (d, 2H), 7.36 (t, 1H), 7.27 (m, 1H), 5.90 (s, 1H, NH ), 4.59 (dd, 1H, α), 3.41 (dd, 1H, β), 3.07 (dd, 1H, β), 1. 67 (s, 9H, t-Bu).

IleNCA: ¹ H NMR (300 CDCl ₃ ) 6.65 (s, 1H, NH), 4.25 (d, 1H, α), 1.94 (m, 1H, β), 1.43 (dm, 2H, γ-CH ₂ ), 1.03 (d, 3H, γ-CH ₃ ), 0.94 (t, 3H, δ).

Lys (Boc) NCA: ¹ H NMR (500 CDCl ₃ ) 6.65 (bs, 1H, N _t H), 4.64 (s, 1H, carbamate NH), 4.31 (t, 1H, α), 3.13 (s, 2H, ε), 2.04 (m, 2H, β), 1.84 (m, 2H, δ), 1.48 (m, 11H, γ, t-Bu).

MetNCA: ¹ H NMR (500 CDCl ₃ ) 6.89 (s, 1H, NH), 4.50 (dd, 1H, α), 2.69 (t, 2H, γ), 2.10 (m, 1H, 3), 2.08 (m, 4H, β, δ).

Typical preparation of T4 N-capped homopolymers:

T4-Leu ₁₅

Isoleucine (0.012 g, 0.1 mol) was added to IleNCA (0.200 g, 1.3 μmol) in 2.5 ml of DMF. After stirring overnight under Ar, T4-NCA (0.037 g, 0.050 μmol) was added and the reaction stirred for an additional 72 hours. The white solution was added to 8 ml of H ₂ O. The heterogeneous solution was cooled to 4 ° C., centrifuged, the supernatant was removed and the pellet washed with 8 ml of H ₂ O. The dried residue was washed with 50 ml of ethanol, warmed to 50 ° C. and dried to give a white powder (0.124 g, 55%): ¹ H NMR (500 DMSO) 7.75 (s, T4 aromatic), 7.08 (s , T4 aromatic), 4.11 (dd, α), 1.77 (m, β), 1.38 (m, β, γ-CH), 0.91 (m, γ-CH, γ-CH ₃ , δ).

T4-Phe ₁₅

White powder (58%): ¹ H NMR (360 MHz, DMSO) 7.0-8.1 (NH, aromatic), 4.5 (α), 3.0 (β); MALDI-MS showed the T4-Phe _{1 -5.}

T4-Met ₁₅

White powder (10%): ¹ H NMR (500 MHz, DMSO) 8.0-8.5 (amide NH), 4.4 (α) 2.5 (γ), 2.05 (ε), 2.0-1.7 (β),

T4-Val ₁₅

White powder (14%): ¹ H NMR (500 MHz, DMSO) 7.75 (T4 aromatic), 7.08 (T4 aromatic), 4.35 (α), 3.45 (β), 1.05 (γ).

For these conjugates using protected NCAs, additional separate deprotection steps were necessary:

T4- [Lys (Boc)] ₁₅ (0.256 g, 61 μmol) in 10 ml of CH ₂ Cl ₂ was stirred with trifluoroacetic acid (10 ml) for 2 hours. The solvent was removed by rotary evaporation and the residue was dissolved in 3 ml of H ₂ O and ultrafiltered (washed with Amicon regenerated cellulose, YM1, NMWL 1000, pH 5 H ₂ O 30 ml). The residue was removed in vacuo to give a light brown residue: ¹ H NMR (500 D ₂ 0) 7.82 (s, T4 aromatic), 7.41 (s, T4 aromatic), 4.29 (bs, α), 3.00 (bs, ε ), 2.13-1.70 (m, β, δ, γ); MALDI-MS showed T4-Lys _4-11 range.

T4-Trp _l5 : ¹ H NMR (500 DMSO) 8.25-6.80 (m, aromatic), 4.50 (bs, α), 3.40 (bs, β), 3.00 (bs, β).

Typical preparation of T4 C-capped homopolymers:

To T4 (0.078 g, 100 μmol) in 10 ml anhydrous DMF was added Trp (Boc) NCA (0.500 g, 1.514 mmol). After stirring for 64 h under Ar, the reaction was quenched by addition of 30 ml of H ₂ O. The opaque white solution was cooled to 4 ° C., centrifuged and the pellet washed three times with 25 ml of H ₂ O. The residue was dried in vacuo to give Trp (Boc) ₁₅ -T4 as a brown solid. This material was further purified by ultrafiltration (washed with Amicon regenerated cellulose, YM1, NMWL 1000, pH 5 H ₂ O 30 ml) to give [Trp (Boc)] ₁₅ -T4 (0.400 g, 79%). Provided as a brown-gold solid: ¹ H NMR (500 DMSO) 8.25-6.80 (m, aromatic), 4.50 (bs, α), 3.40 (bs, β), 3.00 (bs, β), 1.50 (bs, t-Bu).

[Trp (Boc)] ₁₅ -T4 (0.509 g) in 8 ml of CH ₂ Cl ₂ : trifluoroacetic acid (1: 1) was stirred for 1.5 hours. The solvent was removed by rotary evaporation and the residue was dried in vacuo to give a brown solid (0.347 g, 97%): ¹ H NMR (500 DMSO) 8.25-6.80 (m, aromatic), 4.50 (bs, β), 3.40 (bs, α), 3.00 (bs, β).

[Lys (Boc)] ₁₅ -T4: ¹ H NMR (500 D ₂ 0) 7.82 (s, T4 aromatic), 7.41 (s, T4 aromatic), 4.29 (bs, α), 3.00 (bs, ε), 2.13 -1.70 (m, β, δ, γ).

Lys _15- T4: ¹ H NMR (500 D ₂ 0) 7.82 (s, T4 aromatic), 7.41 (s, T4 aromatic), 4.29 (bs, α), 3.00 (bs, ε), 2.13-1.70 (m, β, δ, γ).

Typical preparation of random T4 / homopolymers:

T4NCA (0.065 g, 0.1 mmol) and Trp (Boc) NCA (0.400 g, 1.2 mmol) were combined with 4 ml of anhydrous DMF. Triethylamine (11 μl, 0.1 mmol) was added and the reaction stirred under Ar for 44 h. After quenching by addition of 10 ml of H ₂ O, the heterogeneous mixture was cooled to 4 ° C. and centrifuged. The pellet was isolated, washed three times with 10 ml of H ₂ O and dried in vacuo.

To the random T4 / [Trp (Boc)] ₁₅ polymer 10 ml of CH ₂ Cl ₂ : trifluoroacetic acid (1: 1) were added and the reaction stirred for 1 hour. The solvent was removed by rotary evaporation to give the deprotected polymer as a brown solid (0.262 g, 91%) and further purified by ultrafiltration (amicon regenerated cellulose, YM1, NMWL 1000, pH 5 H ₂ 0 30 washed with ml): ¹ H NMR (500 DMSO), 8.25-6.80 (m, aromatic), 4.50 (bs, α), 3.40 (bs, β), 3.00 (bs, β).

Random T4 / Lys _l5 : ¹ H NMR (500 D ₂ 0); 7.82 (s, T4 aromatic), 7.41 (s, T4 aromatic), 4.29 (bs, α), 3.00 (bs, ε), 2.13-1.70 (m, β, δ, γ).

Preparation of Polylysine Defacoat

N-hydroxysuccinimide (0.8 g, 6.9 mmol), dicyclohexylcarbodiimide (1.6 g, 7.6 mmol) and triethylamine (0.9 g, 8.9 mmol) were added CH ₂ Cl ₂ : DMF (6: 1 ) Was added to valproic acid (1.0 g, 6.9 mmol) in 14 ml. After the reaction was stirred for 60 hours, the solution was filtered to remove white precipitate and the solvent was removed on a rotary evaporator. The residue was purified by flash chromatography (10: 1-2: 1 hexanes: EtOAc) to give succinimidyl ester as a clear oil (1.0 g, 59%): R _f (3: 1 hexanes: EtOAc) 0.43; ¹ H NMR (300 MHz, CDC1 ₃ ) 2.76 (s, 4H, succinimide), 2.61 (m, 1H, methine), 1.65-1.19 (m, 8H, methylene), 0.88 (t, 6H, methyl).

Valproic acid succinimidyl ester (0.104 g, 431 μmol) dissolved in 0.4 ml of THF was added to Lys _{14 ′} HBr (0.106 g, 37 μmol) (pH 8) in 0.8 ml of H ₂ O. The reaction was stirred overnight before H ₂ 0 8 ml was added. The pH of this mixture was acidified to 3 with 6 M HC1 and extracted twice with 2 ml of CH ₂ C1 ₂ . The aqueous layer was dried and the residue was dissolved in 1 ml of H ₂ O. The solution was purified by SEC (G-15, 10 ml dry volume) and eluted with water. The fractions containing the conjugate were combined and dried to yield white solids (0.176 mg), with 28 lysines per drug molecule in NMR; ¹ H NMR (D ₂ 0) 4.29 (m, 1H, α), 3.00 (m, 2H, ε), 1.87-1.68 (m, 4H, β, δ), 1.43 (m, γ, methylene), 0.85 ( t, methyl).

Preparation of PolyGlu Mevastatin

AcNGlu ₁₅ (3-mevastatin) ₂

1 ml of pyridine and acetic anhydride (20 μl, 207 μmol) were added to PolyGlu ₁₅ (0.116 g, 69 μumol) in 3 ml of anhydrous DMF. After stirring for 21 hours, the pH of the mixture was acidified to 1 with 6 N HC1 and then cooled to 4 ° C. The white precipitate was collected by centrifugation, washed three times with H ₂ O and dried under vacuum to give 11 mg of N-acetylated polyGlu ₁₅ .

Dicyclohexylcarbodiimide (0.022 g, 108 μmol) was added to N-acetylated polyGlu ₁₅ (0.011 g, 7 αmol) in 4.8 ml of anhydrous DMF. After stirring for 20 minutes, the heterogeneous solution was filtered to remove insoluble dicyclohexylurea and combined with mevastatin (0.042 g, 108 μmol) and N-dimethyl-4-aminopyridine (0.013 g, 108 μmol). . After the mixture was stirred for 23 hours, 20 ml of H ₂ O was added to quench the reaction. The solution was extracted twice with 10 ml of CHCl ₃ . The pH of the aqueous component was adjusted to 3 with 1 N HCl and cooled to 4 ° C. The resulting white precipitate was isolated by centrifugation and washed three times with H ₂ 0 8 ml. The solid was dissolved in 1 ml of H ₂ O, washed with 1 ml of CH ₂ Cl ₂ , and twice with 2 ml of EtOAc. The pH of the aqueous layer was acidified to 3 with 1 N HCl, cooled to 4 ° C., the precipitate was isolated by centrifugation and washed twice with H ₂ O 2 ml. ^{In 1} H NMR, the dried conjugate (2 mg) contained 15 Glus per two mevastatin molecules: ¹ H NMR (500 MHz, DMSO) 5.92 (5 'mevastatin), 5.72 (3' Mevastatin), 5.19 (4'mevastatin), 5.17 (8'mevastatin), 5.12 (3 mevastatin), 4.41 (5 mevastatin), 4.03 (α, Glu), 2.25 (γ, Glu), 1.88 ( β, Glu), 0.82 (4 ", 2 'allyl methyl mevastatin), 1.17 (2" mevastatin).

Glu ₁₅ (3-mevastatin) (160)

Dicyclohexylcarbodiimide (0.239 g, 1.159 mmol) was added to Glu ₁₅ (0.151 g, 77 μmol) in 3 ml of anhydrous DMF and the reaction was stirred under Ar for 4 hours. The white precipitate was removed and N-dimethyl-4-aminopyridine (0.141 g, 1.159 mmol) and mevastatin (0.222 g, 0.569 mmol) dissolved in 10 ml of CHCl ₃ were added. The reaction was stirred under Ar for 21 hours and then the precipitate was removed. The solution was concentrated by rotary evaporator and added to 40 ml of saturated NaCl (aq) adjusted to pH 8. The heterogeneous solution was extracted three times with 20 ml of CHCl _{3 and} then ultrafiltered (Amicon regenerated cellulose, YM1, NMWL 1,000). Dry the regeneration water in vacuo to yield 8 mg of white residue, which is glutamic acid ratio was 15 for 1 mevastatin gae in ^{1 H NMR: 1 H NMR (} 500 D 2 0); 5.92 (5'mevastatin), 5.72 (3'mevastatin), 5.19 (4'mevastatin), 5.17 (8'mevastatin), 5.12 (3 mevastatin), 4.41 (5 mevastatin), 4.03 (α, Glu), 2.25 (γ, Glu), 1.88 (β, Glu), 0.82 (4 ", 2 'allyl methyl mevastatin), 1.17 (2" mevastatin).

BocGlu (3-mevastatin) O-t-Bu

N-dimethyl-4-aminopyridine (0.055 g, 453 μmol) was added to BocGlu (OSu) Ot-Bu (0.181 g, 453 αmol) and mevastatin (0.177 g, 453 μmol) in 40 ml of CHCl ₃ . The reaction was heated to reflux under Ar for 7 hours and then stirred at 20 ° C. for 8 hours. The solvent was removed by rotary evaporation and the residue was purified by flash chromatography (8: 1-1: 1 hexanes: EtOAc) to give a conjugate as a clear film (0.038 g, 11%): R _f (3: 1 Hexanes: EtOAc) 0.22; ¹ H NMR (CDCl ₃ 500 MHz) 5.97 (d, 1H, 5 '), 5.73 (dd, 1H, 3'), 5.55 (s, 1H, 4 '), 5.32 (s, 1H, 8'), 5.24 (dd, 1H, 3), 5.09 (d, 1H, NH), 4.48 (m, 1H, 5), 4.20 (m, 1H, α), 2.78 (m, 2H, 2), 2.37 (m, 4H, 2 ', 2 ", y), 1.45 (s, 18H, t-Bu), 1.12 (d, 3H, 2" -CH ₃ ), 0.88 (m, 6H, 4 ", 2'-CH ₃ ).

Preparation of PolyGlu Prednisone

BocGlu (21-Prednisone) O-t-Bu

Dicyclohexylcarbodiimide (0.544 g, 2.64 mmol) was added to BocGlu-Ot-Bu (0.400 g, 1.32 mmol) in 20 ml of CHCl ₃ . The reaction was stirred for 1 hour and filtered to remove insoluble dicyclohexylurea. N-dimethyl-4-aminopyridine (0.320 g, 2.64 mmol) and prednisone (0.472 g, 1.32 mmol) were added. The reaction was stirred for 60 hours and filtered. The solvent was removed by rotary evaporator and the residue was purified by flash chromatography (10: 1-0: 1 hexanes: EtOAc) to give the target as a transparent film (0.256 g, 31%): R _f (6: 1 CHCl ₃ : MeOH) 0.54; ¹ H NMR (CDC1 ₃ 500 MHz) 7.68 (d, 1H, 1), 6.16 (d, 1H, 2), 6.04 (s, 1H, 4), 5.15 (d, 1H, NH), 5.03 (d, 1H , 21), 4.71 (d, 1H, 21), 4.08 (t, 1H, α), 1.40 (s, 18H, t-Bu).

Glu (21-prednisone)

Trifluoroacetic acid (1.5 ml) was stirred with BocGlu (21-prednisone) Ot-Bu (0.060 g, 93 μmol) in 15 ml of CH ₂ Cl ₂ for 1 hour. The solvent was removed by rotary evaporation and the residue was purified by flash chromatography (8: 1 CHCl ₃ : MeOH) to give a clear film: R _f (6: 1 CHCl ₃ : MeOH) 0.13 ¹ H NMR (CDCl ₃ 500 MHz) 7.72 (d, 1H, 1), 6.25 (d, 1H, 2), 6.14 (s, 1H, 4), 5.14 (d, 1H, 21), 4.75 (d, 1H, 21), 4.10 (t , 1H, α).

Example  19

Polymerization of L-Glutamic Acid NCA by Amine-Initiation

The polyglutamic acid conjugate of atenolol was successfully synthesized using the following method.

MW (g / mol) 266.3 173 1538 (n = 10)

Mass (mg) 77 500 446 = 100%

mmol 0.29 2.89 0.29

Equivalent 1 10 1

DMF is anhydrous dimethylformamide and was purchased from Aldrich.

Glassware was dried in an oven prior to use.

1. Glu-NCA (500 mg, 2.89 mmol) was dissolved in 4 mL of DMF and stirred under Ar in a 15 mL round bottom flask equipped with a gas inlet tube.

2. Athenolol dissolved in 1 mL of DMF was added to this Glu-NCA solution and stirred for 72 hours at room temperature. In general, the reaction can be carried out by tlc until there is no free amine initiator. For this reaction, tlc was performed using a silica plate and eluted with 20% methanol in ethyl acetate.

3. Pour 20 mL of 10% sodium bicarbonate (pH = 8) in water to quench the reaction.

4. The water was washed with 3 x 20 mL of methylene chloride and 3 x 20 mL of ethyl acetate.

5. The pH of the combined aqueous layers was 6 with 6N HCl and rotary evaporated to reduce the volume to about 20 mL. This solution was then cooled in the refrigerator for over 3 hours.

6. To precipitate the polymerization product, the aqueous solution was acidified to approximately pH 2 with 6N HCl and placed in the refrigerator again for 1-2 hours.

7. Divide the suspension into 10 mL test tubes, centrifuge for 15 minutes until the precipitate forms a solid mass at the bottom of the test tube, then drain the water (at this point in the method, the solids are removed through a filtration funnel It is preferable to filter and wash with acidic water, since this solid is too difficult to filter, atenolol is centrifuged).

8. The solid was then resuspended in acidic water (about pH 2) and vortexed, then centrifuged again and the water decanted. This method was repeated one or more times for a total of three washes.

9. The solid was then dried under high vacuum overnight to give 262 mg (59%) of polymer. NMR analysis showed a Glu / Athenolol ratio of about 30/1.

Example  20

Monolayers of Caco-2 human intestinal epithelial cells are increasingly used to predict the uptake of drugs delivered orally. We assessed the performance of Polythroid using the Caco-2 transwell system and other in vitro assays. These results suggest that polysteroids can increase oral delivery of thyroid hormones to treat hypothyroidism.

In vitro performance

Caco-2 Human Intestinal Epithelial Cell Analysis

Caco-2 cells were grown on collagen coated 24-well well surfaces to form a front culture monolayer representing small fragments of the intestine. The wells were removable and included a top chamber representing the apical side (toward the lumen of the intestine) and a bottom chamber representing the basolateral side. The integrity of the epithelial wall was monitored by testing the electrical resistance through monolayers. The absorbency of the drug could be studied by applying a sample to the top side and analyzing the concentration of drug in the basal side chamber after incubation.

Intestinal Epithelial Cell Protease Cleavage Polythroid

Polysroids are synthetic polymers of glutamic acid with T4 and T3 covalently attached by peptide bond linkages. The polymer is a delivery vehicle for thyroid hormones and is designed not to pass through the walls of the small intestine itself. Rather, it was designed to release T4 and T3 in a time dependent manner. The release of thyroid hormones depends on the enzymatic cleavage of the glutamic acid polymer. Theoretically, this will arise from polysteroids that encounter proteolytic enzymes as they enter the gut. The protein is cleaved into small polypeptides by pancreatic enzymes secreted into the stomach pepsin and small intestine. Small intestinal epithelial cells then function to further cleave small polypeptides. This is accomplished by proteolytic enzymes called brush border proteases attached to the cell surface.

In order to monitor the effect of brush-shaped peptidase on polysteroids, it is necessary to develop an assay that specifically distinguishes polysteroids from polyglutamic acid and thyroid hormones. Therefore, we have developed an enzyme-linked immunosorbent assay (ELISA) that specifically recognizes polysteroids. This assay utilizes antibodies against glutamic acid polymers to capture polysteroids, and antibodies against T4 or T3 to detect the presence of polysteroids. The assay does not have cross reactivity with polyglutamic acid or the thyroid hormone itself. Thus, the proteolysis of the polythroid releases T4 and T3 from the polymer and correspondingly reduces ELISA reactivity. Therefore, polysteroid specific ELISAs can be used to monitor the degradation of polysteroids.

Polysteroid specific assays were used to analyze in situ degradation of polysteroids in Caco-2 cell culture. Various concentrations of polythroid were added to the top of Caco-2 cells and incubated for 4 hours in PBS at 37 ° C. (n = 4). Upper polythroid concentrations were measured by polysteroid specific ELISA before and after 4 hours of incubation (FIG. 6). At relatively high concentrations of 100 micrograms, 26% of the polysteroids were degraded, whereas at 10 times lower concentrations, 84% of the polysteroids were degraded. When a concentration of 0.5 micrograms (which is closer to the gut concentration at normal human dose) was added, the amount of polythroid remaining after 4 hours of incubation was below the detection limit of ELISA (10 ng), which was In essence, it means complete decomposition. Since the basal outer chamber did not contain a detectable polythroid in any experiment, the loss of polymer in the upper chamber was not due to the absorption of the polythroid across the monolayer (see below). We cannot rule out the cellular uptake of polysroids, but it seems that most of them, if not all, are reduced, probably due to enzymatic degradation. At higher concentrations, it would be difficult to think of intracellular uptake as the cause of this large difference in the remaining polysteroids.

Polysroid Caco -2 crossing the fault T4 To increase the absorption.

Uptake of T4 was observed in the Caco-2 transwell system (n = 4). Polythroid (10 micrograms) was added to the top of the transwell. T4 was added to the top at the same concentration as the T4 concentration of the polythroid. Using a commercial ELISA for T4, T4 concentration in the basolateral chamber was measured after incubation at 37 ° C. for 4 hours (FIG. 7). Much higher amounts of T4 were taken up from polysroids compared to Caco-2 cells incubated with the same amount of T4 as T4 contained in the polymer.

Polysroid Caco -2 Do not cross the fault.

To determine if the polystriode itself traverses the Caco-2 monolayer, we incubated with the polystride at high concentrations (100 micrograms) and then polysroid specific to measure the amount of polymer in the basolateral chamber. ELISA was used. After incubation for 4 hours, samples obtained from the basolateral side (n = 4) showed no reactivity in this ELISA (FIG. 8). The detection limit for the polythroid is 10 ng, so less than 1 / 10,000 polysteroids were absorbed. In conclusion, polysteroids did not cross the Caco-2 monolayer within the limit of ELISA detection.

In stomach and bowel simulators Polysroid  decomposition

Pepsin secreted by the gastric mucosa is the only protease that is active under acidic conditions of the stomach. The pancreas secretes into the intestine a number of proteolytic enzymes that degrade proteins and polypeptides. In theory, these endogenous proteases will be involved in the release of T4 and T3 from the polysteroid as the polymer descends into the digestive tract.

We tested polysteroids in USP gastric simulators and USP intestinal simulators and compared the digestibility for polysteroids synthesized by other methods. Samples of polythroid differ in position at the thyroid hormone attachment site. Samples were dissolved in gastric simulator buffer containing pepsin or intestinal simulator buffer containing pancreatic enzyme extract (pancreatin) and incubated at 37 ° C. for 24 hours. After digestion, the samples were analyzed by HPLC for the content of released monomers T4 and T3. 9 and 10 show the levels of T4 and T3 after digestion in gastric and intestinal simulators. Release varied according to thyroid hormone attachment site. Polysroids with T4 and T3 attached to the C-terminus (C-capped) had the highest digestibility. On the other hand, polysteroids attached to the N-terminus (N-capped) were not digested in the gastric simulator and showed relatively low digestion in the gut simulator. Randomly attached polysteroids showed only minimal digestibility in gastric simulators and moderate digestibility in intestinal simulators. In conclusion, the release of thyroid hormone from polysteroids varies depending on the method of synthesis. This fact provides a means to control (correctly tune) the time release of oral delivery.

Conclusion and Summary

The following conclusions can be obtained from in vitro performance assays:

* T4 and T3 are released from the polysteroid by pancreatic and intestinal cell proteases.

* T4 and T3 released from the polysteroids are absorbed across the long monolayer.

Polysroids increase the uptake of T4 across the intestinal epithelium in vitro.

* Polysroid itself does not pass through the intestinal epithelial wall in vitro.

* The rate of time release can be controlled by the polysteroid synthesis method.

Covalent binding of T4 and T3 to polypeptides offers many potential advantages for oral delivery for tyrosine hormone replacement therapy. Proteolytic enzymes produced by pancreatic and intestinal epithelial cells release T4 and T3 from polysteroids. Thus, T4 and T3 should be released in a time dependent manner as they descend into the digestive tract. Once released thyroid hormone is absorbed through the intestinal epithelium in a Caco-2 cell model. In addition, data obtained from an in vitro intestinal epithelial cell model suggest that attachment of glutamate to the intermediate of glutamic acid may possibly increase the uptake of thyroid hormone by providing a second absorption mechanism and / or elevating the solubility of thyroid hormone. Polythroid itself does not cross the intestinal epithelial wall in the in vitro Caco-2 model. Thus, since the polymer is not absorbed into the bloodstream, any concern about the systemic effects of the polymer is minimized.

Although specific embodiments have been described and described above, the invention is nevertheless not limited to the details described above. Rather, various modifications may be made in detail within the scope and range of the claims without departing from the true spirit thereof.

The invention will be best understood upon reading the following detailed description in conjunction with the accompanying drawings. Included in the drawings are the following drawings.

1 shows the acid activator / N-terminal scheme of the present invention.

2 shows an amine activator / C-terminal scheme of the present invention.

3 shows an alcohol activator / N-terminal scheme of the present invention.

Figure 4 shows the alcohol activator / glutamic acid dimer preparation and conjugated reaction scheme of the present invention.

5 shows the mechanism of the alcohol activator from glutamic acid dimer scheme.

Figure 6 shows in situ digestion of polysteroids in intestinal epithelial cell culture.

7 shows the T4 concentration at the base side.

8 shows the polythroid concentration of the base to base side.

9 shows T4 analysis in the gastric simulator colon simulator.

10 shows T3 analysis in the gastric simulator colon simulator.

Claims (18)

Polypeptides, and Activators other than amino acids Wherein the active agent is an alcoholic drug that is covalently bound to the polypeptide via alcohol to release the drug into the bloodstream by extracellular enzymes after oral administration, orally ingestible tablets, capsules or oral suspensions A composition for oral administration in the form. The composition of claim 1, wherein the polypeptide consists of one or more of 20 natural amino acids. The composition of claim 1, wherein the polypeptide consists of one or more amino acids selected from glutamic acid, aspartic acid, arginine, asparagine, cysteine, lysine, threonine, and serine. The composition of claim 2, wherein the polypeptide consists of glutamic acid. The composition of claim 2, wherein the polypeptide consists of serine. The composition of claim 2, wherein the polypeptide consists of lysine. The composition of claim 1, wherein the drug is bound to the C-terminus. The composition of any one of claims 1 to 6, wherein the drug is bound to the N-terminus. The composition of any one of claims 1 to 6, wherein the drug is bound to the side chain of the amino acid. Polypeptides, and Activators other than amino acids Wherein the active agent is a carboxylic acid drug covalently bound to the polypeptide via a carboxylic acid such that the drug is released into the bloodstream by extracellular enzymes after oral administration, orally ingestible tablets, capsules Or a composition for oral administration in the form of an oral suspension. The composition of claim 10, wherein the polypeptide consists of one or more of 20 natural amino acids. The composition of claim 10, wherein the polypeptide consists of at least one amino acid selected from glutamic acid, aspartic acid, arginine, asparagine, cysteine, lysine, threonine, and serine. The composition of claim 12, wherein the polypeptide consists of glutamic acid. The composition of claim 12, wherein the polypeptide consists of serine. The composition of claim 12, wherein the polypeptide consists of lysine. The composition of claim 10, wherein the drug is bound to the C-terminus. The composition of claim 10, wherein the drug is bound to the N-terminus. The composition of claim 10, wherein the drug is bound to the side chain of the amino acid.

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