MXPA01004487A - Hyperpolarized helium-3 microbubble gas entrapment methods - Google Patents

Abstract

Methods for increasing the T1 of injectable microbubble formulations of hyperpolarized 3He include the step of introducing the hyperpolarized 3He to a quantity of microbubbles held in a chamber and increasing the pressure therein to facilitate the movement or loading of the 3He into the microbubbles. Subsequently, a limited quantity of carrier liquid or a carrier liquid solution alone, or pre-mixed with 3He, can be introduced to the microbubble/3He in the chamber to inhibit the tendency of the 3He to leach out of the bubble. Related pharmaceutical products and associated containers as well as an evacuation based method for rapid mixing and delivery of the bubbles and the 3He is also disclosed. An additional method for dissolving 129Xe gas by using bubbles as an accelerant is also described.

Description

GAS ENTRAMPING METHODS FOR HYPERPOLARIZED HELIO-3 MICROBURBS FIELD OF THE INVENTION The present invention relates generally to hyperpolarized Helium-3 ("3He"), and in particular is suitable for magnetic resonance imaging ("MRI") and medical diagnostic applications by NMR spectroscopy.

BACKGROUND OF THE INVENTION Typically, MRI has been used to produce images by exciting the nuclei of hydrogen molecules (present in water protons) in the human body. However, it has recently been discovered that polarized noble gases can produce improved images of certain areas and regions of the body, which have so far produced little less than satisfactory images in this embodiment. It has been found that 3He and Xenon-129 ("129Xe") polarized are particularly suitable for this purpose. Unfortunately, as will be explained later, the polarized state of the gases is sensitive to the handling and environmental conditions and, as a drawback, may decay from the polarized state relatively quickly.

The "polarization" or hyperpolarization of certain noble gas nuclei (such as 129Xe or 3He) above the natural or equilibrium levels, ie, Boltzmann polarization, is desirable because it improves and increases the MRI signal strength, allowing Doctors get better images of the substance in the body. See the patent of E.U.A. No. 5,545,396 issued to Albert et al., The disclosure of which is hereby incorporated by reference in its entirety. For medical applications, after producing hyperpolarized gas, it is processed to form a non-toxic or sterile composition before introduction to a patient. Unfortunately, during and after collection, hyperpolarized gas can deteriorate or decay (lose its hyperpolarized state) relatively quickly, and therefore must be handled, collected, transported and stored with care. The decay constant "TT related to the longitudinal relaxation time of hyperpolarized gas is often used to describe the amount of time a gas sample needs to depolarize in a given container.The handling of the hyperpolarized gas is decisive, due to the sensitivity of the hyperpolarized state to environmental and management factors, and to the potential for the undesirable decay of the gas from its hyperpolarized state to the planned final use, that is, supply to a patient, processing, transportation and storage of hyperpolarized gases, as well as gas delivery to the patient or end user can expose the hyperpolarized gases to various relaxation mechanisms, such as magnetic gradients, environmental and contact impurities, etc. In the past, various modes of supplying hyperpolarized materials have been proposed. , as injection and inhalation, to introduce the hyperpolarized gas to a patient. Inhalation of hyperpolarized gas is almost always preferred for pulmonary or respiratory-type images. Other channels and supply techniques can be used to focus on other regions. However, since helium is much less soluble than xenon in conventional vehicle fluids, such as lipids or blood, 3He has been used almost exclusively to reproduce the image of the lungs more than other target regions. Recent developments have proposed to overcome the problem of low solubility of helium by using a suspension of microbubbles. See Chawla et al., In vivo magnetic resonance vascular imaging using laser-polarized 3He microbubbles, 95 Proc. Natl. Acad. Sci. USA, pp. 10832-10835 (September 1998). Chawla et al. suggest the use of radiographic contrast agents as the injection fluid to deliver the hyperpolarized 3He gas microbubbles in an injectable formulation. This formulation can then be injected to a patient to reproduce the image of a patient's vascular system. As has been mentioned in general, one way currently used to load or produce the microbubble mixture is by "passive" permeability.; that is to say almost always, the hyperpolarized 3He enters the walls of the microbubbles with the permeability of the helium of the bubble itself. In this way, this gas charging method can carry an undesired amount of time, which can allow the hyperpolarized gas to drop unduly. Furthermore, contact with the fluid or even the microbubble can cause contact-induced depolarization, which can dominate the mechanisms of hyperpolarized 3He relaxation and cause an undesirable reduction in the hyperpolarized life of the gas. As such, there remains a need to improve 3He microbubble formulations and loading methods to minimize polarized gas decay and improve the Ti of the microbubble formulation. In addition, there is also a need to increase the solubility ease of hyperpolarized gaseous xenon, which in the past has been problematic.

OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION Therefore, an object of the present invention is to improve Ti for an injectable solution in hyperpolarized 3He microbubbles. Another object of this invention is to reduce the contact-induced depolarization effect to increase the hyperpolarized life of a product for injectable microbubbles.

A further object of this invention is to produce an injectable microbubble solution so as to increase the concentration of hyperpolarized 3He in the microbubbles in the injectable formulation. Another object of this invention is to provide methods and devices for administering injectable formulations in polarized microbubbles to a subject in a manner that can rapidly mix and deliver the formulation to take advantage of the polarized state of the gas before it decays deleteriously. Another object of this invention is to process and form a mixture of hyperpolarized 3He gas in improved containers and injection supply systems that are configured to inhibit depolarization in the collected polarized gas. Still another object of the invention is to provide methods, surface materials and containers that will minimize the depolarization effects of the hyperpolarized state of the 3He gas in a microbubble solution attributed to one or more paramagnetic impurities, oxygen exposure, diffuse magnetic fields and relaxation by surface contact. Another object of the invention is to provide an auxiliary method of dissolution to facilitate the transition of hyperpolarized 129Xe from a gaseous to a liquid state. These and other objects are met by the present invention, which is directed to products of injectable solution with hyperpolarized gas in relation to microbubbles (solubilized or liquid) and in relation to the production and delivery methods, system and apparatus. A first aspect of the invention is directed to a method for producing an injectable formulation of hyperpolarized 3He. The method includes the steps to introduce a plurality of microbubbles into a chamber and then direct a quantity of hyperpolarized 3He in the chamber with the plurality of microbubbles. The pressure in the container increases above one atmosphere. A quantity of liquid is then directed to the chamber after having placed therein the amount of hyperpolarized gas and microbubbles. The microbubbles with hyperpolarized 3He (full) come in contact with the liquid, so that an injectable formulation of hyperpolarized 3He microbubbles is produced. In a preferred embodiment, the pressure increases above two atmospheres, and preferably increases between approximately 2-10 atm. It is also preferred that the augmentation step be carried out after introducing the microbubbles into the chamber and before introducing the liquid therein. Preferably, the liquid solution is selected so as to inhibit depolarization of the gas based on contact therewith. For example, in one embodiment, the fluid is selected to have low solubility values for 3He (preferably less than about 0.01, and more preferably less than about 0.005 -008) or a diffusion coefficient value elevated for 3He. In operation, the surface or walls of the microbubbles are configured in the absence of the injection liquid to allow the hyperpolarized 3He to enter freely through the outer cage of the bubble cage, then the fluid or liquid envelops the openings in the shell in the form of a cage to trap the hyperpolarized gas in it, so as to inhibit the transfer or leakage of gas from the microbubble. In addition, or alternatively, the fluid itself is introduced in a relatively limited amount which can reduce the pressure differential between the 3He in the bubbles and those in the fluid and / or an amount of 3He can be pre-mixed with the liquid solution. The reduced pressure differential (saturation or equilibrium of 3He in the external fluid of the bubbles) can reduce the amount of 3He that migrates from them. furthereven if the 3He leaves the bubble, the low solubility of the selected fluid can reduce the amount of helium migration from the bubble to equilibrium / saturation to prolong the polarization related to it, thus prolonging the Ti of the bubble. injectable mixture in microbubbles. In fact, fluid selection will be an important factor in establishing a sufficiently long Ti for the injectable formulation itself. Alternatively, or in addition, for formulations directed to 3He dissolved in liquid, it is preferable that the liquid has a high diffusion coefficient for 3He (high diffusion preferably means about 1.0x10"5 cm2 / s and more preferably at least 1.0x10"). "4 cm2 / s).

Another aspect of the invention is directed towards a method for mixing and formulating polarized gaseous 3He for injection in vivo. The method includes the steps for introducing a quantity of microbubbles into a container and applying vacuum to the container. Also, the method includes directing a first amount of hyperpolarized 3He gas in the evacuated container with the microbubbles, and directing a second quantity of a fluid in the container thereafter to form a bubble solution. The bubble solution is then removed from the container and injected into a subject. Preferably, the second amount of fluid comprises a substantially deoxygenated fluid and the injection step includes supplying the bubble solution to a catheter placed in situ that is inserted into the vein of a subject. It is also preferred that the mixing portion of the method be temporarily carried out close to the injection step (preferably performed within about 30 seconds prior to injection). A further aspect of the present invention is directed to a method for solubilizing gaseous hyperpolarized 129Xe. The method includes the steps for introducing a first quantity of bubbles in a chamber and directing a second amount of hyperpolarized 129Xe in the chamber, so that at least a portion of the 129Xe contacts the microbubbles. The method also includes the steps to dissolve a portion of 129Xe and then substantially remove all microbubbles from 129Xe prior to delivery of the dissolved phase of 129Xe to a subject. The microbubbles act as an accelerator to solubilize 129Xe from a gaseous state. Even another aspect of the invention is a pharmaceutically injectable fluid hyperpolarized product in vivo. The product includes a first quantity of microbubbles formed of a first material and a second amount of hyperpolarized 3He. The product also includes a third amount of a liquid vehicle solution. The third amount is less or substantially equal to the sum of the first and second quantities. Preferably, the microbubbles have an approximate size of less than 10 μm in diameter and the injectable product has a single bolus size of around 50 cc's. The present invention includes methods to increase the density of 3He in each microbubble (increase in charge density) and to increase the density of bubble packing to "pack" the bubbles with higher density in the solution. Each can provide one or more more intense signal strength and more effective Ti. In addition, the present invention can allow smaller measured amounts of 3 He bolus. For example, microbubble injection volumes with hyperpolarized venous gas of approximately 5-50 cc's, and more preferably around 15-30 cc's, can provide a sufficient signal for clinically useful images. Preferably, the microbubble formulations of this invention are also formed so that the gas microbubbles have the size of less than about 10 μm and more preferably about 8 μm or less in diameter, so that they can be injected into a venous side of the circulatory system and then pass through the capillaries to the arterial side of the circulatory system. For convenience, one or more of the charge gases in the bubble, and the delay in its escape, and fluid packing and fluid compatibility may facilitate the delivery of 3 He quantities in a manner that allows the gas to be injected. in a target area in sufficient quantity and strength to provide clinically useful information. The present invention, by recognizing the very limited life (Ti) of the microbubble formulations, also provides a rapid mixing and delivery device that can allow the bubble mixture and formulation preparation to temporarily approach the injection point ( preferably with injection through a catheter). Likewise, the present invention allows an NMR coil to be placed and / or operatively related to the microbubble formulation (in the permanence chamber of the bubble formulation filled with gas or associated conduits, catheters or residence chamber rods and the like) to allow a polarization measurement to be conveniently obtained together with a planned supply to better calibrate the signal intensity and / or the supply of depolarized substances.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates a shell in the form of a microbubble cage (the specific configuration and size of the opening or openings in the "shell" is attributed to the molecular structure of the bubble material itself) and the charging method in accordance with present invention. Figure 1A schematically illustrates an alternative embodiment of a microbubble structure in accordance with the present invention. Figure 2 schematically illustrates an apparatus or introduces a liquid into a microbubble and mixture of hyperpolarized 3He gas. Figure 3 schematically illustrates the liquid of Figure 2 which forms an outer wall or closes the cage-shaped openings in the shell of the microbubble to trap the hyperpolarized gas therein. Figure 4 schematically illustrates the microbubble mixture of Figure 2 which is removed from the mixing container in preparation for injection of a predetermined amount into a blank. Figure 5A is a schematic illustration of a previous view of an evacuation supply and mixing system. Figure 5B is a schematic illustration of a front view of Figure 5A showing the removal of a syringe (the syringe and container are illustrated in exaggerated scale for ease of representation) and injectable delivery technique.

Figure 6 is a block diagram of a method for formulating an injectable microbubble product.

DETAILED DESCRIPTION OF THE INVENTION In the following, the present invention will be described in greater detail hereinafter with reference to the accompanying drawings, in which the preferred embodiments of the invention are illustrated. However, the invention can be modalized in many different forms and should not constitute a limit to the embodiments explained herein, but rather these modalities are provided so that the description is thorough and complete, and will fully carry the scope of the invention to those skilled in the art. Similar numbers refer to similar elements throughout the text. In the figures, certain features have been exaggerated for clarity or drawn for purposes of illustration, and as such, the figures are not drawn to scale. For example, a typical microbubble has such a size that it is much larger (preferably about 10 μm or less) than a 5 A atom of 3 H (for example about 2,000 times larger). In addition, it will be appreciated that the molecular formation of the bubble (corresponding to the particular bubble material or materials) will provide the specific configuration and size of the opening or openings and the structure of the shell and walls and the figures therein is only intended of schematic representation and explanation.

BACKGROUND OF POLARIZED RELAXATION PROCEDURES Once hyperpolarized, there is an upper limit theoretically on the relaxation time (Ti) of the polarized gas based on the relaxation of shock explained by fundamental physics, ie, the time it takes a sample determined to decay or depolarize due to shocks of hyperpolarized gas atoms together without other depolarization factors. For example, 3He atoms relax through a dipole to dipole interaction during 3He-3He shocks, while 129Xe atoms relax through a spin spin interaction NI (where N is the moment molecular angular and I designates nuclear spin rotation) during the 129Xe-129Xe crashes. In other words, the angular momentum associated with the movement of a nuclear spin is retained by the angular momentum of the shock atoms. In any case, since both procedures occur during clashes of noble gas to noble gas, both resulting relaxation rates are directly proportional to the gas pressure (Ti is inversely proportional to the pressure). Therefore, in one atmosphere, the theoretical relaxation time (T-i) of 3He is around 744-760 hours, while for 129Xe, the corresponding relaxation time is around 56 hours. See Newbury et al., Gaseous 3He- 3He Magnetic Dipolar Spin Relaxation, 48 Phys. Rev. A, No. 6, p. 4411 (1993); Hunt et al, Nuclear Magnetic Resonance of 129Xe in Natural Xenon, 130 Phys. Rev. p. 2302 (1963). Unfortunately, another relaxation procedure prevents the realization of these relaxation times in theory. For example, 129X and 3He gaseous shocks with container walls ("surface relaxation") have historically dominated most relaxation procedures. For 3He, most of the longest known relaxation times have been achieved in special glass containers that have low helium permeability. In the past, a fundamental understanding of the surface relaxation mechanism has been elusive, which has complicated the predictable ability of the related T. The patent of E.U.A. No. 5,612,103 issued to Driehuys et al., Describes the use of coatings to inhibit nuclear spin relaxation induced by hyperpolarized noble gas surfaces, especially 129Xe. The description of this patent is hereby incorporated by reference in its entirety. Driehuys et al, recognized that the nuclear spin relaxation of 129Xe in a surface coating of polydimethoxy siloxane ("PDMS") can be mastered by the dipolar coupling of the nuclear spin of 129Xe to the protons in the polymer matrix. In this way it was shown that paramagnetic contaminants (such as the presence of paramagnetic molecules, such as oxygen) were not the dominant relaxation mechanism in that system, since it was discovered that dipole to nano-nuclear dipole relaxation dominates the system under investigation. This was because 129Xe was substantially dissolved in the particular polymer matrix (PDMS) under investigation. See Bastiaan Driehuys et al, Surface Relaxation Mechanisms of Laser-Polarized 129Xe, 74 Phys. Rev. Lett. No. 24, pp. 4943-4946 (1995).

Background of relaxivity of materials To compare the characteristic information of certain materials that concern their respective relaxation effects in hyperpolarized noble gases, the term "relaxivity" is used. As used herein, the term "relaxivity" ("Y") is used to describe a property of material related to the depolarization rate ("1 / T-?") Of the hyperpolarized gas sample. See patent application of E.U.A. copending and co-assigned No. 09 / 126,448, entitled Containers for Hyperpolarized Gases and Related Methods, the disclosure of which is incorporated herein by reference in its entirety. Generally speaking, the dissolved gas on the surface of the polymer relaxes rapidly (less than one second), so that most of the hyperpolarized gas in the container is in the form of free gas. Therefore, the relaxation of this gas occurs through continuous exchange between the free gas and the dissolved gas in the polymer. In material quantities, the velocity of this gas exchange can be described by the "sorption parameters" -solubility ("S"), diffusion coefficient ("D") and permeability ("P"). Permeability is the transmission of atoms or molecules through a film (polymer). It depends on the chemical and physical structure of the material, as well as the structure and physical characteristics of the permeating molecules. Permeability can be defined as the product of solubility and the diffusion coefficient ("P = SxD"). Solubility ("S") is a measure of how much permeant can dissolve in a given material. The diffusion coefficient ("D") is a measure of the random mobility of the atoms in the polymer. In this way, the polymer sorption parameters can be used to characterize the relaxation of hyperpolarized gases in the presence of permeable surfaces. As described in the patent application referred to above, the relaxation rate ("Tp") in terms of the polymer can be rewritten as a function of T, rp = 1 / T | P. Solving for the relaxation time Ti: This analysis can be extended in three dimensions to produce: where Vc is the internal volume of the chamber, Ap is the exposed surface area of the polymer and S is the solubility of the gas in the polymer. The inverse relationship between Ti and S is a key observation of this development. There is also a dependence of the apparent inverse square root on the diffusion coefficient Dp. However, the relaxation time in polymer 1 / TP also depends on Dp, which cancels the general effect on T-i. This leaves solubility as the dominant sorption characteristic in the determination of T-i. 3He microbubble relaxation considerations The hyperpolarized 3He is introduced to at least three different contact relaxation relaxation mechanisms when formulating the suspension mixture: the related parameters of the injection container, such as size, shape and material (as well as the materials of the seals and other components located in proximity) of the container, the related microbubble parameters, such as size, shape and material and the injection fluid material. The container will be explained in more detail below, but preferably it is configured and formed from materials that accept polarization well. Described in general, microbubbles act as a miniature container to retain hyperpolarized 3He. As such, preferably, the gas is introduced into the "bubble" in an efficient way to relaxation. Furthermore, the structure of the microbubble is preferably such that 3He can freely enter the bubble through the outer walls in the absence of the injection liquid. Even, the preference bubble is charged so that it retains an increase in 3He amounts. This invention provides various suitable material structure alternatives and loading methods for microbubble configurations in combination with different injection fluids and related material property values that are preferred therefrom., when they are related to hyperpolarized 3He to optimize the injectable solution of Ti microbubbles. In addition, those skilled in the art will appreciate that the thickness of the shell or typical bubble wall is much thinner than the critical length scale Lp (defined and explained below) for example, for silicone, D = 4.1e "5 cm2 / s and Tp = 4.5s, and the related length scale is around 100 μm In contrast, the wall thickness of a typical bubble can be 5-6 orders of magnitude thinner (approximately 100A), so Significantly reduces the role of the bubble wall in the depolarization analysis.Thus, the Ti of the 3He gas in the bubble is not less than the Ri of 3He in the fluid, that is, allows the increase or improvement of the acquisition time of the image or regions of objective image formation more distant from the injection point.

Load Assuming that the microbubble is a spherical bubble of radius "R" and related area ("A") of the shell with thickness of shell "? X" and that the initial volume of gas (Vg) that exists in the shell of the Bubble is determined by the product of the gas solubility in the shell material (S), the external gas density of the shell [G] 0, and the shell volume (? xA), then: Vg = S [G] 0? XA (2) The time it takes for this volume of gas to permeate the interior is limited by diffusion. Nominally, this time is given by t = (? X2 / D). In this way, the volume of gas that permeates the shell by unit time can be expressed by: S [G] DA Xv. dt g Vx (2) A more complex analysis can take into account the constitution of the gas inside the bubble and the resulting differential equation. When the concentration of the inner gas is formed, the transfer of gas from the outside will decrease and equilibrium will be reached in the form of a charge capacitor. However, an optimal working calculation of how long the "charge" of the interior of the bubble with 3He polarized takes can be obtained without this analysis.

This charging time can be described as Í '~ = K < 4 > where (V) is the interior volume of the bubble. Therefore, in accordance with equation 5, the loading time calculations of the hyperpolarized gas in the bubble can be calculated as / car a = 3S [C] D (5) For example, assuming that R = 5μm) 5 x 10"4 cm and [G] 0 = 1 Amagat and a helium solubility of S * 0.01 (which is typically for most preferred materials), and the use of a Estimated of a helium diffusion coefficient in LDP that is D = 6.8 x 10 ~ 6 cm2 / s and an extremely thin wall? x = 100A = 10"6 cm, the diffusion time is calculated as a t" 2.5 ms reasonable. For a larger wall thickness, in the order of? X = 1 μm) 1.0 x 10"4 cm, the loading time increases to 0.25s, which despite being slower, is still relatively good.

Increasing the charge density As shown in Figure 2, another way to increase the Ti of the microbubble mixture is to increase the density or amount of 3 He charged in the microbubble. This increase in charge density can be obtained by increasing the pressure in the preparation container to force the additional quantities of 3He into a microbubble 10. Increasing the density of the polarized 3He in a microbubble 10 can prolong the effective Ti of the solution . For example, escaping 3He may act to balance the solution surrounding the microbubble, thereby helping to retain the partial amounts of the hyperpolarized 3He that is protected-isolated within the bubble. Another advantage to increasing the charge density is that the increase in 3He amounts in the microbubbles can produce greater signal strength. Preferably, for charging, the microbubble spheres are placed in the container, hyperpolarized gas is introduced by a hermetic seal in the container and the pressure in the container 30 is increased above atmospheric pressure, preferably in the scale of approximately 2-8 atm, and more preferably above 8 atm, and even more preferably up to about 10 atm, to create more bubbles packed with density.

Introduction of the ligule As will be appreciated by those skilled in the art, almost always a microbubble that is structurally configured (at a molecular level) to allow the entry of molecular 3He, will almost always also allow its exit with ease. In this way, it is preferred that, once the hyperpolarized gas is inside the bubble, the bubble and / or the liquid mixture act to prevent or inhibit the exit of the gas from inside the bubble. In a preferred embodiment, the liquid in the solution or mixture is selected such that, if the hyperpolarized gas leaves the bubble, it contacts the liquid having a low solubility for 3He, thus limiting the total amount of 3He. that comes out of the bubble. "Low solubility" includes solutions selected so that they have a solubility for 3He ("S") that is less than about 0.01, and preferably less than about .008, and more preferably less than about .005. Alternatively, for target solutions at the 3He facility dissolved in the mixture, the liquid can be selected so that the polarized 3He has a high diffusion coefficient therewith. Preferably, "high diffusion" means the diffusion coefficient rates above 1 x 10"6 cm2 / s, and preferably greater than about 6 x 10" 6 cm2 / s, and more preferably even above approximately 1.0 x 10"5 cm2 / s, and even more preferably even in the order of at least 1.0 x 10" 4 cm2 / s. For convenience, a T, prolonged for the solution can be achieved for 3He dissolved in fluid by selecting a fluid that has a high diffusion coefficient for 3He. The present invention recognizes that the formulation of the microbubble injection can be improved by optimizing the microbubble structure itself to provide a faster transport of the 3He therein. Preferably, the improved structure is provided by the formulation of a substantial amount of the bubbles with a surface contact material that is selected to have a low solubility value for 3 He. In an alternative embodiment, the microbubble material is selected so as to have a relatively thin wall and a high diffusion coefficient value for 3 He, which allows the 3 He to move in the bubble more rapidly.

Preferably, the bubbles are dimensioned and configured with thin bubble wall thicknesses and miniaturized microbubble diameters. As used herein, "thin" means a bubble wall thickness of less than about 6 microns, and more preferably a wall thickness of about 1-2 microns. "Miniaturized" includes diameters of microbubbles that are less than about 10 microns, and preferably less than about 8 microns. The miniaturized size of the bubbles in particular is preferred for perfusion-related images, so that the bubbles are approximately 8 microns, so that they can move freely in and / or through the capillaries. Referring to Figure 1, one embodiment of this invention recognizes that a microbubble 10 can be formed for convenience from a material that is physiologically compatible and has a cage-like structure with walls that can allow faster transport of hyperpolarized gas 20 in the microbubble 10. The walls 15 of the microbubble define an opening 15a which is preferably dimensioned, so that it is slightly larger than the 3He. The 3He atom is in the order of approximately 2Á-5Á in diameter, and therefore, the opening 15a in the wall of the microbubble is preferably greater than 2Á. An alternative embodiment of the microbubble is illustrated schematically in Figure 1A, in which a microbubble 10 'has cage-shaped walls 15'.

In operation, as illustrated in Figure 2, the 3He 20 and the microbubbles 10 are placed in a container that brings the polarization closer and the hyperpolarized 3He 20 enters freely into the opening or openings 15a in the microbubble until it reaches a state of equilibrium. substantial. Preferably, the transport time (the time it takes the gas to enter the microbubbles) at a pressure increase (above 1 atm) is below about 1 minute for a single dose amount. That is, in a preferred embodiment, a quantity of microbubbles is introduced into a properly prepared and hermetically sealed container (first). The pressure in the container then rises above 1 atm, preferably at around 2-8 atm, and more preferably above 8 atm, and even more preferably at around 10 atm. A quantity of 3He polarized gas is subsequently directed to the container. The pressure facilitates the tendency of a portion of the hyperpolarized 3He to enter the structure of the bubble. Of course, the pressure can also be increased during the introduction of the 3He or even soon after (or even before the introduction of the microbubbles, although it is not preferred). Preferably, the liquid is also injected into the container while the pressure is raised. The high pressure of the liquid may be at the same pressure substantially or a reduced high pressure of the charging pressure of the microbubble / hyperpolarized gas. Also, as illustrated in Figure 2, after a predetermined (relatively short) transport time (almost always less than about one minute, as already indicated, that is, the time for at least a 3He polarized portion to be move in the structure of the bubble), a liquid or fluid 40 is introduced into the container 30. In a preferred embodiment, it is preferred that the liquid 40 be selected so that the 3He has low solubility for the fluid ("S" less to about 0.01, and more preferably less than about .008, and more preferably even less than about .005). The low solubility helps to inhibit the polarization decay, and preferably covers the gaps or openings in the wall of the microbubbles, so that the 3He 20 exit of the microbubble is inhibited. As illustrated in Figure 4, liquid 40 surrounds the microbubble, and since 3He is substantially insoluble in the fluid, the 3He 20 is repelled by contact with the liquid 40. Furthermore, as illustrated in figure 3, the liquid forms an outer wall 41 of the microbubble 10, thus effectively "trapping" the 3He 20 in the microbubble. Of course, as already indicated, the liquid can also be selected so that it has a high diffusion coefficient for 3He. In any case, 3He 20 and microbubbles 10 together with a solution or mixture of fluid form an injectable formulation that preferably provides an injectable volume of a single dose which is about 5-50 cc's and preferably about 15-30 cc's The selection of the liquid introduced into the microbubble / combination of hyperpolarized 3He is important. As already explained, the liquid 40 is selected so as to provide a relatively long Ti for the hyperpolarized gas, since the gas can leave the microbubble or come into contact with the fluid, when it tries to diffuse through the walls of the liquid. the microbubble. For in vivo applications, it is preferred that the injection liquid be selected to be non-toxic or non-depolarizing to the hyperpolarized gas. Preferably, the liquid will be selected so that it has a low proton density along with the low solubility for 3He, as already indicated. Preferably, the proton density is less than or equal to about 125 moles / L, and more preferably less than about 120 moles / L, and still more preferably less than about 115 moles / L. It is further preferred, for liquids having a relatively high oxygen solubility value, that the liquid be processed to be more compatible with the hyperpolarized gas. For example, it is preferred that the liquid be at least partially deoxygenated and / or partially deionized before introduction into the transport container or container with the hyperpolarized gas. It is more preferred that the liquid be sterilized and substantially deoxygenated and / or substantially deionized. Other modifications and treatment procedures can also be performed on liquids to make them more compatible with polarization. For example, certain elements of the liquids can be replaced or deuterated and the like. Of course, a plurality of liquids may also be employed as the fluid component, as a mixture or combination of the liquid, whether miscible or immiscible. Tests indicate that water is a suitable liquid (preferably deoxygenated), as well as D2O. Water is compatible and substantially does not depolarize 3He. Other liquid vehicles are known, such as those described in PCT / US97 / 05166 to Pines et al. Previously, as indicated in the patent application of E.U.A. Copending and co-assigned No. 09 / 163,721, entitled Hyperpolarized Noble Gas Extraction Methods, Masking Methods, and Related Transport Containers, with the approximate addition of 20 cubic centimeters of partially degassed water in the chamber of a 250 ml container changed The related Ti of the gas in the container from about 8 hours to about 5 hours. The content of this application is hereby incorporated by reference in its entirety. For a microbubble mixture comprising deoxygenated water as the filler wall 41, a calculation of the Ti of 3 He in said microbubble mixture can be described by equation 1.10. For the calculation, an estimate of the solubility of helium and density of protons in the fluid is established. The solubility of helium in water as mentioned by Weathersby et al., In Solubility of inert gases in biological fluids and tissues, Undersea Biomedical Research 7 (4), 277-296 (1980), is given as 0.0098. The proton density of water is 111 mol / L (compared to 131.4 for LDPE). In this way, the ratio of water relaxivity to LDPE relaxivity is (0.0098 / 0.006) (111/131) 1 2 = 1.5. Knowing that the LDPE relaxivity is around 0.0012 cm / min., the water relaxivity value is approximately 0.0018 cm / min. In this way, to obtain an estimate of T-i, the volume of the bubble is divided by the surface area. For an 8 micron bubble, the V / A is approximately 2.7x10"4cm and Ti is around 0.15 min (9 seconds) .The doubling of the bubble diameter to 16 microns can increase the time to 18 seconds. of D20 as the fluid can produce Ti of about 36 seconds.Figure 6 is a block diagram of the preferred method for forming an injectable 3H microbubble solution.A quantity of microbubbles is introduced into a container (or gas holding chamber). (block 100) Preferably, the microbubbles have a diameter size that is approximately 10 μm or less (block 102), then a quantity of hyperpolarized 3He gas is introduced into the container (block 110). the container is increased above atmospheric pressure (block 120), preferably between 2-10 atmospheres of pressure (block 122) Of course, the pressure can be increased before introducing the 3He or, more preferably, subsequent concurrent with the introduction of 3H3 in the container. The liquid (or liquid solution or mixture) is then introduced into the container (block 130), preferably after a "transit" time of predetermined duration. Preferably, the liquid is pre-selected to have one or more of low solubility for 3 He, a high diffusion coefficient for 3 He, and where it is appropriate to deoxygenate and / or substantially deionize (block 132). The liquid may be limited in quantity (block 134) and / or premixed with another quantity of hyperpolarized gas (block 136). The liquid and microbubble / 3He are then combined or reduced together to form the injectable microbubble formulation (block 140). Preferably, the injectable formulation has the size of a dispensable bolus less than or equal to about 50 cc's (block 142).

Bubble packing It is preferred that the amount of liquid introduced into the chamber with the microbubble / 3He mixture be restricted to an amount approximately equal to or less than the volume of the combined volumes of 3He and microbubbles to pack the 3He into the charged microbubble. " When the volume of the liquid decreases, the intensity of the signal based on it may increase, and less dilution of 3He in the environment makes the solubility appear lower. For example, a ratio of 2 to 1 or 1 to 1 of liquid to gas / microbubbles or less that is, 20 cc's of microbubbles, 40 cc's 3 He and 60 cc's of liquid will produce a 1-1 ratio. Alternatively, or in addition, the increase in amounts of polarized 3He can be added initially to the liquid (premixed) to inhibit the tendency of 3He to migrate from the bubbles, providing at least residual amounts of 3He within the liquid itself. This can constitute the quantity in the solution and reduce the leakage of the microbubbles. This additional or "surplus" of 3He can be added to the liquid before or concurrently with the introduction of the liquid into the microbubble mixture in the container. For example, for a mixture comprising approximately 20 cc's of microbubbles, 20cc's of gas, and a liquid in an amount less than about 40 cc's, an amount of 20 cc of 3He can be introduced into the liquid (before the introduction into the container). ) to form the combined premix liquid which is then directed to the chamber with 3He and microbubbles. In other words, the present invention recognizes that the T-i of the solution is sensitive to the dilution of bubbles in the liquid. The maximum reduction of the liquid introduced into the mixture can minimize the difference in the equilibrium in the liquid mixture, which in turn, should reduce the amount of depolarization that occurs due to the leakage action. As such, a larger fraction of 3He will remain inside the bubble. The saturation corresponds to the solubility, which is a volume / volume measurement of about 0.01, in accordance with this invention. As an alternative, or in addition, the addition of a liquid with previously introduced amounts of helium gas (ie, the premix solution can also reduce the partial pressure difference in the combined mixture, which can also facilitate the permanence of a fraction greater than 3He within the bubble These "bubble pack" methods, particularly when used with a low solubility liquid, can result in a formulation with Ti.In addition, with the use of deuterated water for the solvent or liquid (or a component thereof) may also help to increase Ti. Due to the relatively short life of the 3He formulation in injectable microbubbles, it is preferred that a rapid delivery and mixing system be used to administer the formulation to a subject temporarily related to the start of the sequence of images, ie, the pharmaceutical-grade in vivo microbubble formulation was mixed at the site, temporarily and physically close to or related to the injection point, preferably mixed in about 30 seconds of the injection time, and more preferably, mixed rapidly and effectively in almost 10 seconds of the injection time. In any case, in operation, preferably a measurement is taken before or concurrently with the injection through an NMR coil 31 in the injection container or supply route (conduit, syringe body, etc.) to affirm / determine the level of polarization of the solution to allow the correlation of the signal intensity with the polarized level of the hyperpolarized solution that is supplied. As shown in Figure 4, the injection mixture 45 is removed from the mixing chamber / transport container 30 in a syringe 70 (Figure 5B) which is placed in a port or septum operably related to the valve 50 in the base of the container, so that the mixture restricted to the liquid can be easily removed (with the help of gravity). The valves 50, 51 are also used to control the pressure of the container.

Typical valves include Luer Lok ™ valves, glass valves, such as those available from Konte Kimbles ™, and polymer material valves known to those skilled in the art can also be employed. Of course, other methods and extraction devices can also be used, such as those described in the co-pending and co-assigned patent application mentioned above. Preferably, the syringe 70 and any packing and valves placed next to it are formed or coated with materials (at least gas contacting surfaces) that accept polarization well, as will be explained below. In addition, containers and syringes and other gas contact devices are preferably prepared to remove impurities for magnetic and magnetic, as well as oxygen and the like, as will also be explained in more detail below. In addition, capillary stems and other separation and isolation means can be used to separate potential depolarization valve elements from the polarized gas, as explained in the U.S. patent application. co-pending or co-assigned No. 09 / 334,400, the contents of which are hereby incorporated by reference in their entirety.

Methods based on vacuum. In an alternative microbubble manufacturing method, a vacuum-type microbubble formulation method is employed. With respect to Figures 5A and 5B, a number of microbubble shells 10 can be introduced under vacuum to an evacuated container (clean / prepared) 30. An amount of gaseous 3He can be directed to the container (the vacuum pulls the gas into the container). The evacuated state of the microbubbles induces the 3He gas to enter and / or rapidly fill the microbubble shells. Next, a sub-container 70, such as a syringe, which is filled in advance with a liquid vehicle solution (such as deoxygenated fluid, liquid or water) can be injected into the container 30. The container 30 can be reoriented to allow the subcontainer , as a syringe 70 is filled with (preferably saturated) the bubble / 3He polarized solution / liquid solution. As illustrated in Figure 5B, the filled syringe can then be peeled off and inserted into a catheter placed in the subject. Alternatively, an LUER LOK ™ valve system can be operated to direct the solution into the duct in the catheter and inject. In operation, the vacuum of preference is pulled to at least 50 microns (militor), and more preferably to at least 10 microns. In this way, the evacuated method also allows a relatively fast supply and mixing system.

Containers Preferred container materials include aluminosilicates, such as Pyrex ®, or hyperpolarized gas that contacts surfaces formed of materials that include high purity and non-magnetised metal films, high purity metal oxides, high purity insulators or semiconductors ( as high purity silicon) and polymers. As used herein, "high purity" includes materials having less than about 1 ppm of ferrous or paramagnetic impurities, and more preferably less than about 1 ppb of ferrous or paramagnetic impurities. Preferred polymers for use in the containers described herein include materials that have a reduced solubility for the hyperpolarized gas. For the purposes of the inventions herein, the term "polymer" is broadly constructed to include homopolymers, copolymers, terpolymers, and the like, and mixtures and combinations thereof should also be included. The terms "their combinations and mixtures" include immiscible and miscible mixtures and mixtures. Examples of suitable materials include, but are not limited to, polyolefin (eg, polyethylenes, polypropylenes), polystyrenes, polymethacrylates, polyvinyls, polydienes, polyesters, polycarbonates, polyamides, polyimides, polynitriles, cellulose, cellulose derivatives and their mixtures and combinations. It is more preferred that the coating or surface of the container comprises a high density polyethylene, polypropylene of approximately 50% crystallinity, polyvinylchloride, polyvinyl fluoride, polyamide, polyimide or cellulose and their combinations and mixtures. See also the co-assigned and co-assigned US patent application No. 09 / 334,400, the contents of which are hereby incorporated by reference in their entirety. Of course, polymers can be modified, for example, by using halogen as a substituent or by placing the polymer in deuterated (or partially deuterated) form (replacement of hydrogen protons with deuterons) can reduce the rate of relaxation. Methods for deuterating polymers are known in the art. For example, the deuteration of hydrocarbon polymers is described in the U.S.A. Nos. 3,657,363; 3,966,781, and 4,914,160, the descriptions of which are hereby incorporated by reference in their entirety. Almost always, these methods use catalytic replacement of deuterons by protons. Preferred deuterated hydrocarbon polymers and copolymers include paraffins, deuterated polyolefins, and the like. Said polymers and copolymers and the like can also be interlaced, in accordance with known methods. It is further preferred that the polymer be substantially free of contaminants or paramagnetic impurities, such as color centers, no electrons, dyes, other fillers of degradation and the like. Any plasticizer or filler employed should be chosen to minimize the magnetic impurities that it makes contact with, or placed next to the hyperpolarized noble gas. Alternatively, in another embodiment, the contact surface can be formed from a metal of high purity. The high purity metal can provide conveniently low relaxivity / surfaces resistant to depolarization relative to the hyperpolarized noble gases.

As already indicated, any of these materials can be provided as a surface coating on an underlying substrate, or formed as a layer of material to define a surface that accepts contact. If used as a coating, it can be applied by any variety of techniques, as will be appreciated by those skilled in the art (eg, by solution coating, chemical vapor deposition, melting bond, sintering powder and the like). Likewise, hydrocarbon grease can be used as a coating. The storage container or container may be rigid or elastic. Rigid containers can be made of Pyrex ™ glass, aluminum, plastic, PVC or similar. The elastic containers are preferably formed as collapsible bags, such as collapsible polymer or metai film bags. Examples of materials that can provide oxygen resistance as well as low solubility include, but are not limited to, PET (polyethylene terephthalate), PVDC (polyvinylidene dichloride), Tediar ™ (polyvinyl fluoride), cellophane and polyacrylonitrile. Preferably, care is taken to ensure that all adjustments, seals and the like that contact or are located relatively close to the hyperpolarized gas are made from materials that either accept polarization or do not substantially degrade the polarized state of hyperpolarized gas. For example, as already explained, many seals available in the market include fluoropolymers or fillers and the like which are not particularly good for the preservation of hyperpolarized 3He gases, due to the solubility of the material with the hyperpolarized gas. Since many common joint materials are fluoropolymers or contain unwanted fillers, they can potentially have a substantial depolarization effect on the gas. In particular, this can be critical especially with respect to 3He. This can be attributed to the relatively high solubility of helium in most fluoropolymers, due to the larger void space in the polymer that can be attributed to the large fluorine atoms. In fact, preliminary tests indicate common packaging materials (such as Viton ™, Kel-F ™, ethylenepropylene, Buna-N ™, and silicone) that exhibit even worse relaxation properties than expected from the relaxation rate of pure polymers. . The more conventional packages depolarize so much that they can dominate the relaxation of a complete hyperpolarized gas chamber. In fact, commercial ethylenepropylene packages present 1 / 3-1 / 2 relaxation time compared to pure LDPE with 29Xe. The faster rate of relaxation can be explained because the magnetic impurities in the packages can be introduced by them, such as dyes and fillers and the like. Therefore, it is preferred that the containers of the present invention employ seals, gaskets, gaskets and the like with substantially pure hydrocarbon materials (basically without magnetic impurities), such as those containing polyolefins. Examples of suitable polyolefins include polyethylene, polypropylene, copolymers and mixtures thereof, which have been modified to minimize the amount of fillers with magnetic impurities that are employed herein. Additional suitable seals include hydrocarbon grease and hydrocarbon seals and gaskets made of polyethylene and the like. In this way, if a valve is used to contain the gas in the chamber 30, it is preferably configured with a reduction of magnetic impurities (at least the surface) the packing and / or with hydrocarbon grease. Of course, since fillers and plasticizers are used, it is preferred that they be selected to minimize magnetic impurities; a preferred material is substantially pure black smoke. In an alternative embodiment, the packing seal can be configured with the exposed surface coated with a high purity metal, as explained for the surface of the container. Similarly, the package or seal may be coated or formed with an exposed outer layer of a polymer of at least "LP" thickness. For example, a layer of pure polyethylene can be placed on a package available in the market. A commercially available packaging material that is preferred for 129Xe is a Teflon ™ coated rubber gasket or a low-relaxivity polymer, as already explained. The hollow spaces in Teflon ™ (although it is a fluoropolymer) do not affect 129Xe, as they affect 3He, because 129Xe is much larger than fluorine, which is much larger than 3He. As already indicated, fluoropolymers can be used as seals with 129Xe, but they are not preferred in use with placements, where the seal can make contact with hyperpolarized 3He. To determine the thickness "Lp", where the thickness of the layer ("Lth") is as thick as the polarization decay length scale ("Lp"), the thickness can be calculated or determined for a particular type of material in accordance with the equation: LP = T. DP (6) where Tp is the nuclear spindle relaxation time of the noble gas in the polymer, and Dp is the diffusion coefficient of the noble gas in the polymer. For example, a layer of substantially pure polyethylene can be placed on a package available on the market. As an alternative, the package or seal can be coated with a surface material, such as LDPE or deuterated HDPE or other material of low relaxivity property. It is also preferred that the relaxivity value "Y" be less than about 0.0012 cm / min for 3 He. To use bags with prolonged surface relaxation times as containers, other relaxation mechanisms can become important. One of the most important additional relaxation mechanisms is due to collisions of the noble gas with paramagnetic oxygen. Since O2 has a magnetic moment, it can relax hyperpolarized gases in the same way as protons. Because of this problem, care must be taken to reduce the oxygen content in the storage container through careful preconditioning of the container, such as by repeated evacuation and pure gas purging procedures. Preferably, the container is processed so that the concentration of O2 produces a T-i of about 1000 hours or more. More preferably, the container is processed to obtain an O2 concentration in the order of about 6.3x10"6 atm or less, or about 10 ~ 7 atm or less, and even more preferably less than about 1x10" 10 atm. In addition, the evacuation / purge procedures. they may include heating the container or other methods of evacuation or pumping to further facilitate the removal of any remaining residue (single-layer) of moisture or water. Preferably, the mixing container / interfaces, syringes and tubes are prepared before use to minimize any necessary preparation at the time of use at the gas injection site. Therefore, the pre-conditioning or equipment preparation methods that are preferred, such as cleaning, evacuation and purging of the components to remove oxygen and paramagnetic contaminants are preferably carried out off-site. After preparation / conditioning, the preconditioned syringes can be stored in the hospital to be used under pressure with a noble gas or benign liquid in them. The pre-filled gas or fluid storage can reduce to a maximum the potential for containers, syringes or components to degas (from the matrix of a material, as oxygen can migrate in the chamber at the contact surfaces) and can also reduce the maximum air leak in the container. As an alternative, or in addition to pre-conditioning, pressurized tubes and supply vessels (and / or syringes) can be sealed with check valves or other ports with valves. In another alternative, vacuum-sealed valves can allow tubes and containers to be stored for use under vacuum, instead of using them under positive pressure. The hyperpolarized gas is collected (and stored, transported and preferably supplied) in the presence of a magnetic field. For 3He, the magnetic field of preference is in the order of at least 5.30 gauss, although once again, higher (homogeneous) fields can be used. The magnetic field can be provided by electric or permanent magnets. In one embodiment, the magnetic field is provided by a plurality of permanent magnets placed on a magnetic anvil that is positioned adjacent the collected hyperpolarized gas. Preferably, the magnetic field is conserved homogeneously around the hyperpolarized gas to minimize field-induced degradation. In operation, the injected hyperpolarized 3He of the present invention can provide signal intensities even in relatively small amounts, which can be detected by known methods of imaging and NMR spectroscopy. In a preferred embodiment, a second amount of 3He is delivered by inhalation to allow a perfusion (injection-based) and ventilation (inhalation-based) VR or "VQ scrutiny" image. Since 3He is used for excitations / data acquisition, for vascular imaging, a simple NMR coil can be used for convenience to obtain both signals.

Xenon Dissolution In addition, microbubbles can be used as a dissolution mechanism to assist in the dissolution of xenon in a liquid, which traditionally exhibits a reluctance to dissolve in a vehicle liquid. As an example, a bottle with a plurality of microbubbles is provided. Then, polarized 129Xe is added to the bottle. A mixture of solvent or liquid (preferably physiologically compatible and non-toxic and sterile) is added to provide an optimum bubble packing fraction (i.e., an amount of liquid as already explained). Alternatively, the quantity of liquid can be increased by a diluted liquid mixture, thus inducing the xenon to leave the bubble to achieve equilibrium. In any case, xenon seeps quickly into the solution outside the microbubble. Preferably, before the injection, the bubbles are forced or filtered to leave a liquid with dissolved xenon. For convenience, the microbubbles can act as an accelerator to aid in the dissolution of xenon in a liquid, which in the past has been problematic and laborious. Of course, since the microbubbles will preferably be filtered from the dissolved xenon, the size of the microbubbles is not limited by the injection of the microbubbles in in vivo systems. Exemplary compatible fluids are described in PCT / US97 / 05166 to Pines et al.

Drug Evaluations Although it is preferred that the injectable formulation be an in vivo formulation of pharmaceutical grade (as a non-toxic and sterilized solution, with the alkali metal separated from the hyperpolarized gas in accordance with FDA regulations for hyperpolarized spin-exchange gases alkali), the present invention is not limited thereto. In fact, rapid advances have been made with the ability to treat and attack many diseases with innovative drug and drug therapies. NMR spectroscopy based on hyperpolarized gases can be used to observe the effects of drugs administered in the body's biochemistry or changes in the drug that occur after administration. This invention may allow for improved sensitivity and higher resolution information potentially for evaluations of treatments or even chemical procedures that encompass a disease state with respect to target tissues or organs within the body. For example, the delivery of the injectable microbubble solution to an animal or target in vitro can evaluate the effectiveness of treatment in terms of progress or regression / improvement of a condition in the pulmonary, cardiac, cerebral or other tissue, organ or system. The foregoing is illustrative of this invention and does not constitute a limit thereof. Although some exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications to the exemplary embodiments are possible without departing materially from the teachings and novel advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the claims. In the claims, the clauses of meaning plus function have the purpose of encompassing the structures described herein when performing the aforementioned function and not only the structural equivalents, but also equivalent structures. Therefore, it will be understood that the foregoing is illustrative of the present invention and does not constitute a limit to the specific modalities described, and that the modifications to the described modalities, as well as other modalities, have the purpose of being included.

Claims (34)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A method for producing an injectable in vivo formulation of 3 °? Hyperpolarized He, comprising the steps of: (a) introducing a plurality of microbubbles into a chamber; (b) directing a hyperpolarized 3He amount in the chamber with the plurality of microbubbles; (c) directing a quantity of liquid in the chamber after having placed therein the amount of hyperpolarized gas and microbubbles; (d) increasing the pressure in the container above one atmosphere; and (e) making contact between the microbubbles and hyperpolarized 3He with the liquid, thus producing an injectable formulation of hyperpolarized 3He microbubbles, where the liquid is selected to provide a sufficiently long Ti for the injectable formulation. according to claim 1, further characterized in that said step to increase includes the increase above two atmospheres 3. A method according to claim 1, further characterized in that the step to increase is performed after said introduction step. . 4. - A method according to claim 3, further characterized in that the step to increase comprises the increase to at least 5-10 atmospheres. 5. A method according to claim 1, further characterized in that the amount of the liquid is substantially equal to or less than the combined volumes of microbubble and hyperpolarized 3He. 6. A method according to claim 1, further characterized in that the amount of hyperpolarized 3He in the chamber is greater than the amount of the liquid. 7. A method according to claim 6, further characterized in that the amount of hyperpolarized 3He in the chamber is at least twice greater than the amount of the liquid. 8. A method according to claim 1, further characterized in that it comprises the step for premixing an additional amount of hyperpolarized 3He with the liquid before said introduction step. 9. A method according to claim 1, further characterized in that the microbubbles have a size less than 10 micrometers in diameter. 10. A method according to claim 1, further characterized in that the liquid comprises a deuterated liquid. 11. - A method according to claim 1, further characterized in that the liquid comprises substantially deoxygenated water. 12. A method according to claim 1, further characterized in that the liquid is substantially deionized. 13. A method according to claim 1, further characterized in that the liquid comprises D2O. 14. A method according to claim 13, further characterized in that liquid has a low proton density. 15. A method according to claim 1, further characterized in that the liquid has a low solubility for 3 He. 16. A method according to claim 1, further characterized in that the microbubble material has a high diffusion coefficient for 3 He. 17. A method according to claim 1, further characterized in that steps (b) to (e) are performed temporarily close to the injection point. 18. A method according to claim 1, further characterized in that the injectable formulation is sized to less than 50cc's. 19. A method according to claim 18, further characterized in that the injectable formulation is sized at a scale of 15-30 cc's. 20. - A method according to claim 5, further characterized in that the injectable formulation is sized on the scale of 5-15 cc's. 21. A method according to claim 1, further characterized in that it comprises the step to measure the polarization of the injectable formulation after the formulation and close to the supply to determine the level of porlarization therein. 22. A method according to claim 1, further characterized in that it comprises the step for acquiring NMR data based on the detection of the hyperpolarized gas delivered in vivo by the hyperpolarized injectable microbubble formulation. 23. A method according to claim 1, further characterized in that it comprises the step to obtain an MRI image based on the detection of the hyperpolarized gas supplied in vivo by the hyperpolarized injectable microbubble formulation. 24. A method according to claim 23, further characterized in that it comprises the step to supply by inhalation a second amount of hyperpolarized 3He gas, and wherein the MR image comprises data related to the hyperpolarized 3He injected and inhaled. 25. A method according to claim 22, further characterized in that it comprises the step to analyze the effectiveness of drug therapies in a white condition based on said acquisition step by NMR. 26.- A method according to claim 1, further characterized in that it comprises the step to measure the level of polarization of the gas 3He close in times of administration of the solution of microbubbles to a subject. 27. A method according to claim 1, further characterized in that the microbubble solution is formulated as a pharmaceutical grade solution, and wherein the microbubble formulation is prepared temporarily close in time to administration to a subject. 28. A method for preparing polarized 3He gas for injection in vivo comprising the steps of: (a) introducing a quantity of microbubbles into a container; (b) apply a vacuum to the container; (c) directing a first quantity of hyperpolarized 3He gas in the evacuated container with the microbubbles; (d) directing a second quantity of a fluid in the container to form a microbubble solution, wherein the fluid is selected to provide a T, long enough for the solution, and wherein the microbubble solution is formulated for injection in. v / Vo on a subject. 29. A method according to claim 28, further characterized in that the second amount of fluid comprises a substantially deoxygenated fluid. 30. - A method according to claim 28, further characterized in that the microbubble formulation is adapted to be delivered in a catheter inserted into the vein of a subject. 31.- A method according to claim 28, further characterized in that steps (b) to (d) are performed temporarily close to the time of injection to a subject, and wherein the method further comprises the measurement of the polarization level of the 3 It has been polarized close to the injection time of the microbubble solution to the subject. 32. A method according to claim 28, further characterized in that steps (b) to (e) are performed in less than about 30 seconds. 33.- A method according to claim 28, further characterized in that it comprises the step of acquiring NMR signal data based on the detection of the hyperpolarized gas supplied to a target by means of the microbubble solution. 34.- A method for solubilizing gaseous hyperpolarized 129Xe, comprising the steps of: introducing a first quantity of bubbles in a chamber; direct a second amount of hyperpolarized 129Xe in the chamber, so that at least a portion of the 129Xe contacts the microbubbles; dissolve a portion of the 129Xe; and substantially separating all microbubbles from 129Xe prior to delivery to a subject.