MXPA98003337A - Methods to incorporate a hydrophobic substance in an acu solution - Google Patents

Abstract

Methods for incorporating a hydrophobic substance into an aqueous solution in a manner which provides a homogeneous composition are described. The hydrophobic substance is at least partially dissolved in an amide to provide an active mixture. The active mixture is then combined with an aqueous solution to form a composition which can then be mixed for a sufficient amount of time to obtain a uniform dispersion. In a particular aspect, the solution may include a surfactan

Description

METHODS TO INCORPORATE A HYDROPHOBIC SUBSTANCE IN AN AQUEOUS SOLUTION Background of the Invention Field of the Invention The present invention relates to methods for incorporating a hydrophobic substance into an aqueous solution. In particular, the present invention relates to methods for incorporating a hydrophobic antimicrobial agent into an aqueous solution in a manner which provides a homogenous antimicrobial composition.

Description of Related Art It has been desirable to incorporate hydrophobic substances in aqueous solutions. For example, it has been desirable to incorporate the hydrophobic antibacterial agents in aqueous solutions to provide antibacterial compositions which can be used in cleaning products and cosmetics such as liquid soaps, shampoos, detergents, lotions and pre-wetted cleaners. However, several problems have occurred when attempting to incorporate hydrophobic substances, such as hydrophobic antibacterial agents, into aqueous solutions.

For example, it has been very difficult to achieve a homogenous or uniformly dispersed mixture when the hydrophobic substances are added to the aqueous compositions. Frequently, the hydrophobic substance has undesirably precipitated in the aqueous compositions. Such nonhomogeneous compositions have also resulted in compositions which have not been completely satisfactory to the consumer due to their cloudy appearance. In an attempt to solve this problem, several conventional compositions have included solvents, such as ethanol and propanol, to achieve the solubility of the hydrophobic substance. However, conventional compositions which have included such solvents have undesirably resulted in dehydration, scab and irritation of the wearer's skin. The use of such solvents has also undesirably resulted in compositions which are highly unstable, relatively volatile and difficult to process.

As a result, it has been necessary to use water-soluble substances in many applications. For example, it has been necessary to use antibacterial agents which readily dissolve in water in many conventional antibacterial compositions. However, such water-soluble antibacterial agents have not been completely satisfactory. For example, many of the water-soluble antibacterial agents are not antimicrobially effective as the hydrophobic antibacterial agents.

In an attempt to achieve homogeneous blends, many conventional compositions have also used large amounts of surfactants or surfactants. However, such large amounts of surfactant have led to excessive foaming of the composition and to compositions which are turbid in appearance. Such excessive foaming and cloudy appearance of the compositions is generally undesirable to the consumer and the consumer is particularly undesirable when the composition is being used in wet cleaners. Typically, consumers of wet cleansers desire solutions which do not foam, or deposit foam on the skin.

Therefore, it is still desirable to provide compositions which are stable, highly effective, homogeneous and non-irritating to the skin. In particular, it is desirable to provide methods for incorporating hydrophobic substances, such as hydrophobic antimicrobial agents into aqueous solutions in a manner which provides a homogeneous composition. For example, it is still particularly desirable to incorporate the hydrophobic antimicrobial agents in the aqueous solutions to provide a clear, homogenous, antimicrobial solution which is non-irritating to the skin and is relatively a foaming agent. It is also desirable that such homogeneous compositions are easily processable. Such methods are particularly desirable for incorporating hydrophobic antimicrobial agents into solutions for conventional wet cleaners.

Synthesis of the Invention In response to the difficulties and problems described above, a new method has been discovered for incorporating a hydrophobic substance into an aqueous solution, in a manner which provides a homogeneous composition. In particular, a new method for incorporating a hydrophobic antimicrobial agent into an aqueous solution has been discovered in a manner which provides a homogenous antimicrobial composition and an antimicrobial composition produced by means of such a method.

As used herein, the term "amide" refers to an organic compound which contains the structural group -C0NH2. Suitable amides have the following structural formula: 0 R C = NH, wherein R is a fatty alkyl group.

As used herein, the phrase "antimicrobial" refers to a composition which prevents the growth of Escherichia coli (ATCC # 11229), Staphylococcus aureus (ATCC # 6538) (both bacteria), and Candida albicans (ATCC # 10231) (yeast) in a Minimum Standard Inhibitory Concentration (MIC) test. The determination of MIC values involves standard microbiological laboratory practices as described in the examples. In general terms, the MIC value was determined by incubating the test organisms in the presence of various dilutions of the composition and monitoring the growth rate. The MIC value is the lowest concentration of the antimicrobial agent which inhibits the growth of the test organism.

As used herein, the term "aqueous" refers to a composition, solution or mixture which contains at least about 50 percent by weight of water, desirably at least about 70 percent by weight of water and more desirably at least about 90 percent by weight of water based on the total weight of the composition, solution or mixture.

As used herein, the term "homogeneous" refers to a composition, solution or mixture whose elements are substantially uniformly dispersed one into the other. For example, a homogeneous composition may include two or more compounds or elements which are essentially uniformly dispersed one within the other. Desirably, the homogeneous composition is relatively clear in appearance. In addition, the homogeneous composition desirably contains very little particulate matter. In one aspect, a homogeneous composition is a composition which has no particulate matter having a size greater than about 1 micrometer.

As used herein, the term "hydrophobic" refers to a substance which is unable to completely dissolve, in an excess of water. In one aspect, a hydrophobic substance is a substance which does not completely dissolve in excess water when allowed to remain for a period of 24 hours.

In one aspect, the present invention relates to a method for incorporating a hydrophobic substance in an aqueous solution to provide a homogeneous composition. The method comprises at least partially dissolving the hydrophobic substance in an amide to form an active mixture and combining the active mixture with the aqueous solution to form the homogeneous composition.

In another aspect, the present invention relates to a method for making an aqueous antimicrobial composition comprising combining an active mixture with a surfactant / water mixture wherein said active, ezcid includes an effective amount of a hydrophobic antimicrobial agent and an amide The active mixture can also be mixed and / or heated before being combined with the surfactant / water mixture. The resulting aqueous antimicrobial composition can be mixed for an effective time duration to make the solution homogeneous. In a particular embodiment, the aqueous antimicrobial composition includes at least about 50 percent by weight of water based on the total weight of the composition.

In another aspect, the present invention relates to a method for making a homogeneous antimicrobial composition comprising (a) at least partially dissolving from about 0.01 to about 3.0 percent by weight of a hydrophobic antimicrobial agent based on a weight total of the composition in from about 1.0 to about 15.0 percent by weight of an amide based on the total weight of the composition to form an active mixture; (b) mixing of from about 1.0 to 30.0 percent by weight of the surfactant based on the total weight of the composition in from about 50 to about 98 percent by weight of water based on the total weight of the composition for form a surfactant / water mixture; and (c) combining the active mixture with the surfactant / water mixture to provide the homogeneous antimicrobial composition.

In still another aspect, the present invention relates to a method for making a homogeneous antimicrobial composition comprising the steps of (a) at least partially dissolving from about 0.01 to about 3.0 percent by weight 2, 4, 4 '-trichloro-2' -hydroxydiphenyl ether based on a total weight of the composition in from about 1.0 to about 15.0 percent by weight of a diethanolamide based on the total weight of the composition to form an active mixture; (b) mixing less than about 10 percent by weight of a nonionic surfactant based on the total weight of the composition in at least about 50 percent by weight of water based on the total weight of the composition to form a surfactant / water mixture; and (c) combining the active mixture with the surfactant / water mixture to provide the homogeneous antimicrobial composition.

In still another aspect, the present invention relates to a method for making an antimicrobial wet cleaner comprising (a) providing an absorbent sheet; and (b) wetting the absorbent sheet with from about 150 to about 600 weight percent of an aqueous antimicrobial composition based on a dry weight of the wet cleaner wherein the antimicrobial composition is made of a method comprising combining a active mixture with a surfactant / water mixture wherein said active mixture includes an effective amount of a hydrophobic antimicrobial agent and an amide. In a particular aspect, the aqueous antimicrobial composition includes at least about 50 percent by weight of water based on the total weight of the composition. In another particular aspect, the antimicrobial composition is made of a method comprising the steps of (i) at least partially dissolving from about 0.01 to about 3.0 percent by weight of a hydrophobic antimicrobial agent based on the total weight of the composition in from about 1.0 to about 15.0 percent by weight of an amide based on the total weight of the composition to form an active mixture; (ii) mixing from about 1.0 to about 30.0 percent by weight of a surfactant based on the total weight of the composition in from about 50 to about 98 percent by weight of water based on the total weight of the composition. the composition to form a surfactant / water mixture; and (iii) combining the active mixture with the surfactant / water mixture to provide the homogeneous antimicrobial composition.

In still another aspect, the present invention relates to an antimicrobial composition and an antimicrobial wet cleaner made by means of the method aspects of the present invention.

Thus, the present invention advantageously provides a method for incorporating a hydrophobic substance into an aqueous solution in a manner which provides a composition. In particular, the present invention advantageously provides a method for making a highly aqueous antimicrobial composition which includes a hydrophobic antimicrobial agent and a relatively large percentage of water. The invention further provides improved processes for incorporating hydrophobic antimicrobial agents into aqueous solutions without the use of solvents which are volatile and highly flammable.

Detailed description of the invention The present invention relates to improved methods for incorporating a hydrophobic substance into an aqueous solution. In particular, the present invention relates to improved methods for incorporating a hydrophobic antimicrobial agent into an aqueous solution to provide a homogeneous antimicrobial composition and an antimicrobial composition made by such methods. The different aspects of the method of the present invention will be described for use in the incorporation of hydrophobic antimicrobial agents in aqueous solutions to provide the antimicrobial compositions for use in conventional wet cleaners. NeverthelessIt should be understood that such methods and the resulting compositions can be used to incorporate other hydrophobic substances such as, for example, surfactants, emulsifiers, emollients, oils and the like into the aqueous solutions which can be used in the manufacture of other consumer products. such as, for example, shampoos, soaps, cleansing agents, detergents, lotions and the like.

It has been found that hydrophobic substances, such as hydrophobic antimicrobial agents, can be used in aqueous solutions to provide homogeneous compositions if the compositions are prepared according to the methods of the present invention. Therefore, according to the different aspects of the method of the present invention, an antimicrobial composition was prepared through a method which involves combining an active mixture of a hydrophobic antimicrobial agent and an amide with an aqueous solution, such as a mixture of water and a surfactant. In a particular aspect of the invention, the homogeneous antimicrobial composition is prepared by means of a method which involves at least partially dissolving an effective amount of the hydrophobic antimicrobial agent in the amide to form the active mixture and separately mixing the water and the surfactant together to form a surfactant / water mixture. The active mixture is then combined with the surfactant / water mixture to provide the antimicrobial composition.

The hydrophobic antimicrobial agent is at least partially dissolved and, desirably, is completely dissolved in the amide before the active mixture is combined with the aqueous solution. For example, the active mixture can be mixed for a period of time to ensure that the hydrophobic antimicrobial agent is essentially dissolved in the amide. In a particular aspect, the active mixture can be mixed for at least about 10 minutes, desirably for at least about 20 minutes, and more desirably for at least about 30 minutes to effectively dissolve most of the agents hydrophobic in the amide. Alternatively, the active mixture can be allowed to remain for a sufficient period of time to at least partially dissolve the hydrophobic antimicrobial agent in the amide. The active mixture can also be heated to dissolve at least one part of the hydrophobic antimicrobial agent in the amide before the active mixture is combined with the aqueous solution. For example, the active mixture may be heated to a temperature of from about 30 to about 50 degrees centigrade and desirably from about 37 to about 45 degrees centigrade to effectively dissolve the hydrophobic antimicrobial agent in the amide. In a particular aspect, the hydrophobic antimicrobial agent is dissolved in the amide so that the active mixture does not contain any particulate matter having a size greater than about 1.0 micrometer. Desirably, the active mixture does not contain any particulate matter having a size greater than about 0.50 microns and, more desirably, the active mixture does not contain any particulate matter having a size greater than about 0.14 microns.

After the active mixture has been combined with the aqueous solution, the antimicrobial composition can also be mixed for an effective amount of time to make the composition relatively homogeneous and essentially reduce the size and number of insoluble particulates. For example, the antimicrobial composition can be mixed for at least about 5 minutes and desirably for at least about 10 minutes to provide a relatively clear homogeneous antimicrobial composition.

A wide range of hydrophobic antimicrobial agents which provide antimicrobial compositions can be used in the various aspects of the present invention. The antimicrobial composition may include a single hydrophobic antimicrobial agent or a combination of two or more hydrophobic antimicrobial agents. Desirably, the hydrophobic antimicrobial agent is a broad spectrum antimicrobial agent. For example, suitable hydrophobic antimicrobial agents include triclosan, triclocarban, and the like, and combinations thereof. Such hydrophobic antimicrobial agents are generally considered to be insoluble in water by those skilled in the art. In a particular aspect, the antimicrobial composition includes triclosan to provide improved antimicrobial effectiveness. As used herein, the term "triclosan" refers to 2,4,4'-trichloro-2'-hydroxydiphenyl ether.

The hydrophobic antimicrobial agent may be present in the composition in an amount which provides an antimicrobial composition. However, if the amount of the hydrophobic antimicrobial agent is too high, the composition may be unclear and irritating to the wearer's skin. In addition, if the amount of the hydrophobic antimicrobial agents is very low, the composition may not be antimicrobially effective as described herein. As stated above, the antimicrobial effectiveness of the antimicrobial composition can be determined by testing the composition against several known microorganisms. It has been found that the antimicrobial compositions of the present invention which include from about 0.01 to about 3.0 percent by weight, desirably from about 0.03 to about 1.0 percent by weight and more desirably from about 0.05. at about 0.7 percent by weight of the hydrophobic antimicrobial agent based on the total weight of the composition are effective against most microorganisms and at the same time are not irritating to the skin. It has also been found that the antimicrobial composition of the different aspects of the present invention is particularly effective if it contains from about 0.01 to about 3.0 percent by weight, and more desirably from about 0.03 to about 1.0 percent by weight. triclosan weight based on the total weight of the composition.

The antimicrobial composition of the different aspects of the present invention may also include other antimicrobial agents which may or may not be considered hydrophobic. For example, the antimicrobial composition may also include p-chloro-m-xyleneol, benzalkonium chloride, chlorhexidine gluconate, hexachlorophene, and the like, and combinations thereof.

A wide range of amides which at least dissolve particularly the hydrophobic antimicrobial agents can be used in the different aspects of the present invention. For example, suitable amides include alkanolamides, long chain fatty acid diethanolamides, long chain fatty acid monoethanolamides, monoisopropanolamides, and the like, and combinations thereof. In a particular aspect, the amide includes at least about 50 percent by weight and desirably at least about 90 percent by weight of a lauric diethanolamide based on a total weight of the amide. It has been found that the use of lauric diethanolamide is particularly desirable because of its solubility in water.

The amide may be present in the antimicrobial composition in any amount which provides the desired composition. However, if the amount of the amide is too high, the composition can be irritating to the user's skin. In addition, if the amount of the amide is too low, the hydrophobic antimicrobial agent may not be dissolved and the composition may not be homogeneous. It has been found that antimicrobial compositions which include from about 1.0 to about 15.0 percent by weight, desirably from about 2.0 to about 10.0 percent by weight, and more desirably from about 3.0 to about 5.0 percent by weight of the amide based on the total weight of the composition are effective. It has also been found that the antimicrobial composition of the various aspects of the present invention is particularly effective when it contains from about 2.0 to about 10.0 and more desirably from about 3.0 to about 5.0 percent by weight of an alkanolamide. based on the total weight of the composition.

A wide range of surfactants can also be incorporated into the aqueous solution of the different aspects of the present invention. It has been speculated that the surfactant acts to prevent precipitation of the active mixture of the hydrophobic antimicrobial agent and the amide in the water. Suitable surfactants include those which prevent such precipitation. For example, suitable surfactants may include anionic surfactants, non-ionic surfactants, cationic surfactants, amphoteric surfactants and combinations thereof as is well known to those skilled in the art. Suitable anionic surfactants include sodium laureth sulfate, methyl lauryl sodium taurate, myristoyl sarcosine, sodium dodecyl benzene sulfonate, and the like.

Suitable nonionic surfactants include the polyoxyethylene ethers of the higher fatty alcohols and the alkyl phenols; polyethylene glycols of fatty acids; the condensation products of alkylol amide fat; polymers of ethylene and propylene oxides; the compounds formed by the addition of propylene oxide to ethylene diamide, followed by the addition of ethylene oxide; the condensation products of ethylene oxide of fatty acid; the carboxylic acid ethoxylate; the ethoxylate glycerides; and the glycol esters. In a particular aspect, the surfactant is a non-ionic surfactant such as an octoxynol-9, which provides an improved composition due to its solubility in water and a low level of skin irritation.

The surfactant may be present in the aqueous solution and an antimicrobial composition in any amount that provides the desired composition. However, if the amount of the surfactants is very high, the composition may not be clear and cause excessive foaming. In addition, if the amount of the surfactant is too low, the active mixture can be precipitated and the composition may not be homogeneous. It has been found that the antimicrobial compositions of the present invention which include from about 1.0 to about 30.0 percent by weight, desirably from about 1.0 to about 20.0 percent by weight and more desirably from about 4.0 to about 10 weight percent of the surfactant based on the total weight of the composition are effective. If it is desired to use the antimicrobial composition in a wet cleaner or a similar product, the amount of the surfactant should not cause excessive foaming of the composition. For example, the antimicrobial compositions according to the present invention which include less than about 10.0 percent by weight and desirably less than about 7.0 percent by weight of the surfactant based on the total weight of the composition have been found to be particularly effective with wet cleaners.

The antimicrobial compositions may also include additional elements such as emollients, perfuming agents, chelating agents, cleaning agents, foam stabilizers, preservatives, protectants, and the like, to improve the performance of the compositions.

Thus, different aspects of the present invention provide antimicrobial compositions which include hydrophobic antimicrobial agents in an aqueous environment. In a particular aspect, the composition of the present invention defines a MIC value of 100 ppm (parts per million active) or less against E. coli (ATCC # 11229) and S. aureus (ATCC # 6538) (both bacteria), and a MIC value of 10,000 ppm or less against C. albicans (ATCC # 10231) (yeast) desirably defines a MIC value of 10 ppm or less against E. coli (ATCC # 11229) and S. aureus (ATCC # 6538) (both bacteria) and a MIC value of 1,000 ppm or less against C. albicans (ATCC # 10231) (yeast), and more desirably defines a MIC value of 1 ppm or less against E .coli (ATCC # 11229) and S. aureus. { ATCC # 6538) (both bacteria) and a MIC value of 1,000 ppm or less against C. albicans (ATCC # 10231) (yeast). Such aqueous antimicrobial compositions are particularly useful in pre-moistened cleaners and in cosmetic products such as liquid soaps, shampoos and lotions.

In another aspect, the present invention relates to an antimicrobial wet cleaner and methods for making wet antimicrobial cleaners which include the antimicrobial compositions described herein. Wet antimicrobial cleaners can appear in several different forms. For example, wet cleaners may be in the form of a stack of wetted sheets which have been packaged in a plastic container. Wet cleaners may also be in the bent or unfolded configuration. further, the wet cleaners may be in the form of continuous fabrics of material which include perforations to separate the individual wet cleaners from the continuous fabric. Such continuous fabrics can be rolled into rolls and also packaged in plastic containers. Such wet cleaners can be used for baby cleaners, hand cleaners, household cleaners, industrial cleaners and the like.

The particular method and sequence of steps for making the wet antimicrobial cleaners described herein is not a limitation to the present invention, but is described only as a method of producing a wet cleaner. Initially, a supply roll of the material being converted in the wet cleaner is unwound to provide a fabric of continuously moving material. The fabric of material is saturated or otherwise impregnated with the antimicrobial compositions of the present invention as described herein, by any suitable means such as spraying, embedding or the like as are well known to those skilled in the art. In a particular aspect, the fabric of material is passed over several perforated tubes which exude the antimicrobial composition inside the material. The amount of the antimicrobial composition which can be added to the material can vary depending on the type of material that is being used to provide the wet cleaner, the type of container being used to store the wet cleaners, and the desired end use of the wet cleaner . Generally, each wet cleaner may contain from about 150 to about 600 weight percent and desirably from about 250 to about 450 weight percent of the antimicrobial composition based on the dry weight of the cleaner. In a particular aspect wherein the wet cleaner is made of a coform material comprising from about 30 to about 40 percent by weight the polymeric microfibers based on the dry weight of the cleaner, the amount of the antimicrobial composition contained within the cleaner wet is from about 300 to about 400 percent by weight and desirably about 330 percent by weight based on the dry weight of the wet cleaner. If the amount of liquid is less than the range identified above, the wet cleaner can be very dry and may not work properly. If the amount of liquid is greater than the range identified above, the wet cleaner may be oversaturated and viscous and the liquid may stagnate at the bottom of the container.

The fabric of the material is then cut in the direction of the machine into multiple tapes, each of which can be folded into the type of bending desired for the individual wet cleaner. For example, the fabric of the material can be cut into eight tapes which can then be folded into a folded configuration. Each folded ribbon can then be combined, one belt on top of the other with the other seven bent ribbons of the same fabric material to form a continuous "sausage". The sausage is then cut into "cuts" of eight pieces of wet cleaners and the clippings of the wet cleaners are arranged in a stacked configuration to form at least one stack of wet antimicrobial cleaners which are then placed in a plastic container.

Suitable materials for the antimicrobial wet cleaner of the present invention are well known to those skilled in the art. The wet cleaner can be made from any material suitable for use as a wet cleaner, including meltblown, coform, and air-laid materials, bonded carded fabrics, hydroentangled materials, and the like, and may comprise natural or synthetic fibers or combinations thereof. the same. The wet cleaner may have a basis weight of from about 25 to about 120 grams per square meter and desirably from about 40 to about 90 grams per square meter. In a particular aspect, the wet cleaner is a coform base sheet of polymeric microfibers and cellulosic fibers having a basis weight of from about 60 to about 80 grams per square meter and desirably about 75 grams per square meter. Such coform base sheets are generally manufactured as described in U.S. Patent No. 4,100,324 issued to Anderson et al. Which was issued July 11, 1978, and which is incorporated herein by reference.

Typically, such coform base sheets comprise a matrix formed of melt-blown microfiber thermoplastic polymeric microfibers, such as, for example, polypropylene microfibers, and cellulosic fibers such as, for example, wood pulp fibers. The relative percentages of the polymeric microfibers and the cellulosic fibers in the coform base sheet can vary over a wide range depending on the desired characteristics of the wet cleaners. For example, the coform base sheet may comprise from about 20 to about 100 weight percent, desirably from about 20 to about 60 weight percent, and more desirably from about 30 to about 30 weight percent. 40 percent by weight of the polymeric microfibers based on the dry weight of the coform base sheet being used to provide the wet cleaner. Alternatively, the wet cleaner 22 can be made from a melt blown sheet of polymeric microfibers having a basis weight of from about 25 to about 120 grams per square meter.

Therefore, different aspects of the present invention can advantageously provide an antimicrobial wet cleaner which, when compared to conventional wet cleaners, has an improved antimicrobial effectiveness and is not irritating to the user. In particular, the different aspects of the present invention can provide an antimicrobial wet cleaner which is moistened with an aqueous antimicrobial composition which includes a hydrophobic antimicrobial agent. Such wet cleansers can advantageously be used for baby cleaners, hand cleaners, face cleaners, cosmetic cleaners, household cleaners, industrial cleaners and the like.

Examples The following examples are presented to provide a more detailed understanding of the invention. The particular materials and parameters are exemplary and it is not intended to limit the scope of the invention.

Example 1 An antimicrobial composition according to the present invention can be prepared as follows. The composition included, based on the total weight of the composition, 1.0 percent by weight of triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether), 4.0 percent by weight of lauric diethanolamide.

(Lauramida DEA), 8.0 percent by weight of Octoxynol-9 (CTFA nomenclature) and the rest of water. The triclosan was added to the lauric diethanolamide and the resulting mixture was heated to about 37.7 degrees centigrade and mixed for about 15 minutes until it was clear. The water and Octoxynol-9 were mixed together. The mixture of triclosan and lauric diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was very clear.

The composition was then subjected to a minimum inhibitory concentration (MIC) technique to determine the lowest concentration of the composition which showed a lower growth rate than the control growth against E. coli (ATCC # 11229), S . aureus (ATCC # 6538) (both bacteria); and C. albicans (ATCC # 10231) (yeast). The protocol used to determine the minimum inhibitory concentration values was a standard microdilution method in a 96-well microplate format. The formulations were prepared by serially diluting each sample of the composition in sterile distilled water at dilutions of 0.01, 0.10, 1.0, 10, 100 and 1000 ppm (parts per million of triclosan). The microplate wells were filled with the diluted formulation, a fixed number of microorganisms, and a growth medium (Mueller Hinton II for E. coli and S. aureus and Saboraud-Dextrose for C. albicans). Inoculations for E. coli, S. aureus, and C. albicans contained 1.3 X 109 CFU / ml, 4.9 X 108 CFU / ml, and 1.0 X 107 CFU / ml, respectively. The microplate was incubated in a THERMOmaxMarca microplate reader, which is commercially available from Molecular Devices Corporation, a business having offices located in Menlo Park, California under model 0200-0600 and 0200-0601, for 18 hours at 37 degrees centigrade. The plate reader was programmed to take optical density readings at 650 nanometers every 30 minutes to monitor the growth rate.

The composition had a MIC value of 1.0 ppm against E. coli. 0.1 ppm against S. aureus and 1,000 ppm against C. albicans. The MIC value is the lowest concentration of the composition which shows a slower growth rate than the positive growth control for each microorganism. The control was the same as the tested composition except that it did not include triclosan. The control did not exhibit any antimicrobial activity at any dilution tested.

Example 2 An antimicrobial composition according to the present invention was prepared as follows. The composition included, based on the total weight of the composition, 0.5 percent by weight of triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether), 4.0 percent by weight of lauric diethanolamide (Lauramide DEA), 5.0 percent by weight of Octoxynol-9 and the rest of water. Triclosan was added to the lauric diethanolamide and the resulting mixture was heated to about 37.7 degrees centigrade and mixed for about 15 minutes until it was clear. The water and Octoxynol-9 were mixed together. The mixture of triclosan and lauric diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was very clear.

Example 3 An antimicrobial composition according to the present invention was prepared as follows. The composition included, based on the total weight of the composition, 0.5 percent by weight of triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether), 3.0 percent by weight of lauric diethanolamide (Lauramide DEA), 5.0 percent by weight of Octoxynol-9 and the rest of water. The triclosan was added to the lauric diethanolamide and the resulting mixture was heated to about 37.7 degrees centigrade and mixed for about 15 minutes until it was clear. The water and Octoxynol-9 were mixed together. The mixture of triclosan and lauric diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was slightly cloudy.

Example 4 An antimicrobial composition according to the present invention was prepared as follows. The composition included, based on a total weight of the composition, 0.5 percent by weight of triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether), 2.0 percent by weight of lauric diethanolamide.

(Lauramida DEA), 5.0 percent by weight of Octoxinol-9 and the rest of water. The triclosan was added to the lauric diethanolamide and the resulting mixture was heated to about 37.7 degrees centigrade and mixed for about 15 minutes until it was clear. The water and Octoxynol-9 were mixed together.

The mixture of triclosan and lauric diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was clear.

Example 5 An antimicrobial composition according to the present invention was prepared as follows. The composition included, based on the total weight of the composition, 0.5 percent by weight of triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether), 3.0 percent by weight of lauric diethanolamide.

(Lauramida DEA), 5.0 percent by weight of disodium capryloamphodipropionate and the rest of water. The triclosan was added to the lauric diethanolamide and the resulting mixture was heated to about 37.7 degrees centigrade and mixed for about 15 minutes until it was clear. The water and the disodium capryloamphodipropionate were mixed together. The mixture of triclosan and lauric diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was cloudy and 5.0 percent by additional weight of disodium capryloamphodipropionate was added to achieve a clear solution.

Example 6 An antimicrobial composition according to the present invention was prepared as follows. The composition included, based on the total weight of the composition, 0.5 percent by weight of triclosan (2, 4, 4 '-trichloro-2' -hydroxydiphenyl ether), 1.0 percent by weight of lauric diethanolamide (Lauramide DEA), 1.0 percent by weight of diethenolamide ryeinol (Rieinolamide DEA) , 5.0 percent by weight of Octoxynol-9 and the rest of water. Triclosan was added to the lauric diethanolamide and the rieinol diethanolamide and the resulting mixture was heated to about 37.7 degrees Celsius and mixed for about 15 minutes until it was clear. The water and Octoxynol-9 were mixed together. The mixture of triclosan and lauric diethanolamide and rieinol diethanolamide was then added to the water mixture and mixed for about 10 minutes. The resulting composition was very clear.

The examples representatively showed that the different aspects of the method of the present invention can be used to incorporate the hydrophobic antimicrobial agents in the aqueous solutions to provide the homogeneous antimicrobial solutions.

Although the invention has been described in detail with respect to specific aspects thereof, it will be appreciated by those skilled in the art to achieve an understanding of the foregoing that alterations, variations and equivalents of these aspects can easily be conceived. Therefore, the scope of the present invention should be assessed as that of the appended claims and of any equivalents thereof.

Claims (27)

R E I V I ND I C A C I O N S

1. A method for incorporating a hydrophobic substance into an aqueous solution comprising at least partially dissolving said hydrophobic substance in one measure to form an active mixture and combining said active mixture with said aqueous solution to form a homogeneous composition.

2. The method as claimed in clause 1, further characterized in that it comprises mixing said active mixture before combining said active mixture with an aqueous solution.

3. The method as claimed in clause 1, further characterized in that it comprises heating said active mixture before combining said active mixture with said aqueous solution.

4. The method as claimed in clause 1, characterized in that said aqueous solution includes at least about 50 percent by weight of water based on the total weight of said composition.

5. The method as claimed in clause 1, characterized in that said aqueous solution includes at least about 70 percent by weight of water based on the total weight of said composition.

6. The method as claimed in clause 1, characterized in that said aqueous solution includes a surfactant.

7. The method as claimed in clause 1, characterized in that said active mixture includes from about 0.01 to about 3.0 percent by weight of said hydrophobic substance based on the total weight of said composition and from about 1.0 to about 15.0 percent by weight of an amide based on the total weight of said composition.

8. A method for making an aqueous antimicrobial composition comprising combining an active mixture which includes an effective amount of a hydrophobic antimicrobial agent and an amide with a surfactant / water mixture to provide said aqueous antimicrobial composition.

9. The method as claimed in clause 8, further characterized in that it comprises mixing said active mixture before combining said active mixture with said surfactant / water mixture.

10. The method as claimed in clause 9, characterized in that it includes mixing said active mixture for at least about 10 minutes.

11. The method as claimed in clause 8, further characterized in that it comprises heating said active mixture before combining said active mixture with said surfactant / water mixture.

12. The method as claimed in clause 11, characterized in that said heating includes heating said active mixture at a temperature of from about 30 to about 50 degrees centigrade.

13. The method as claimed in clause 8, further characterized in that it comprises mixing said aqueous antimicrobial composition for an effective amount of time to make said composition homogeneous.

14. The method as claimed in clause 13, characterized in that said mixing of said aqueous antimicrobial composition includes mixing said composition for at least about 5 minutes.

15. The method as claimed in clause 13, characterized in that said mixing of said aqueous antimicrobial composition includes mixing said composition until said composition does not contain relatively insoluble particles.

16. The method as claimed in clause 8, characterized in that said aqueous antimicrobial composition includes at least about 50 percent by weight of water based on the total weight of said composition.

17. A method for making a homogeneous antimicrobial composition comprising: a) at least partially dissolving from about 0.01 to about 3.0 percent by weight of a hydrophobic antimicrobial agent based on the total weight of said composition in from about 1.0 to about 15.0 percent by weight of an amide based on the total weight of said composition to form an active mixture; b) mixing from about 1.0 to about 30.0 percent by weight of a surfactant based on the total weight of said composition in from about 50 to about 98 percent by weight of water based on the total weight of said composition to form a surfactant / water mixture; and c) combining said active mixture with said surfactant / water mixture to provide said homogenous antimicrobial composition.

18. The method as claimed in clause 17, further characterized in that it comprises mixing said active mixture before combining said active mixture with said surfactant / water mixture.

19. The method as claimed in clause 17, further characterized in that it comprises heating said active mixture before combining said active mixture with said surfactant / water mixture.

20. The method as claimed in clause 17, further characterized in that it comprises mixing said homogenous antimicrobial composition for at least about 5 minutes.

21. A method for making a homogenous antimicrobial composition comprising the steps of: a) at least partially dissolving from about 0.01 to about 3.0 percent by weight of 2,4,4'-trichloro-2'-hydroxydiphenyl ether based on the total weight of said composition in from about 1.0 to about 15. 0 percent by weight of a diethanolamide based on the total weight of said composition to form an active mixture; b) mixing less than about 10 percent by weight of a nonionic surfactant based on the total weight of said composition in at least about 50 percent by weight based on the total weight of said composition to form a surfactant mixture /Water; Y c) combining said active mixture with said surfactant / water mixture to provide said homogenous antimicrobial composition.

22. An antimicrobial composition made by the method of clause 8.

23. A method for making an antimicrobial wet cleaner comprising: a) providing an absorbent sheet; Y b) wetting said absorbent sheet with from about 150 to about 600 weight percent of an aqueous antimicrobial composition based on a dry weight of said wet cleaner wherein said antimicrobial composition is made of a method comprising combining a mixture active which includes an effective amount of a hydrophobic antimicrobial agent and an amide with a surfactant / water mixture.

24. The method as claimed in clause 23, characterized in that the antimicrobial composition includes at least about 50 percent by weight of water based on the total weight of said composition.

25. A method for making an antimicrobial wet cleaner comprising: a) providing an absorbent sheet; Y b) wetting said absorbent sheet with from about 150 to about 600 weight percent of a homogeneous antimicrobial composition based on a total weight of said wet cleaner wherein said antimicrobial composition is made of a method comprising the steps of: i) at least partially dissolving from about 0.01 to about 3.0 percent by weight of a hydrophobic antimicrobial agent based on a total weight of said composition in from about 1.0 to about 15.0 percent by weight of an amide based on the total weight of said composition to form an active mixture; ii) mixing from about 1.0 to 30.0 percent by weight of a surfactant based on the total weight of said composition in from about 50 to about 98 percent by weight of water based on the total weight of said composition for form a surfactant / water mixture; Y iii) combining said active mixture with said surfactant / water mixture to provide said homogenous antimicrobial composition.

26. The method as claimed in clause 25, characterized in that said hydrophobic antimicrobial agent is 2, 4, '-trichloro-2'-hydroxydiphenyl ether.

27. A wet antimicrobial cleaner made by the method as claimed in clause 23. SUMMARY Methods for incorporating a hydrophobic substance into an aqueous solution in a manner which provides a homogeneous composition are described. The hydrophobic substance is at least partially dissolved in an amide to provide an active mixture. The active mixture is then combined with an aqueous solution to form a composition which can then be mixed for a sufficient amount of time to obtain a uniform dispersion. In a particular aspect, the aqueous solution may include a surfactant.