MXPA06008533A - Nanosuspensions of anti-retroviral agents for increased central nervous system delivery - Google Patents

Abstract

The present invention provides compositions comprising dispersions of anti-retroviral agents and methods of manufacture. The nanosuspensions are made by the process of microprecipitation and energy addition. Preferably, the nanosuspensions are made by the tandem process of microprecipitation-homogenization.

Description

NANOSUSPENSIONS OF ANTI-RETROVIRAL AGENTS FOR HIGH SUPPLY IN THE CENTRAL NERVOUS SYSTEM BACKGROUND OF THE INVENTION Technical Field The present invention relates to compositions that contain nanosuspensions of antiretroviral agents and methods for their preparation. The compositions are prepared by means of a microprecipitation and energy addition method. The compositions are particularly useful for delivering an anti-retroviral agent to the brain of a mammal subject to the treatment of VI H infections. Prior Art Drugs and pharmaceutical agents that are used to treat a patient's brain problems or diseases are usually administered orally. However, most drugs ingested do not attack the brain, and instead are metabolized by the liver. The inefficient use of the drug may require the ingestion of higher concentrations of drug that can also be harmful to the liver. In addition, smaller amounts of drugs are able to reach the brain, requiring the patient to take doses more frequently. The most efficient use of the drug can be done both by eliminating the metabolism of the liver and going directly to the brain. One solution to this problem includes supplying a drug using cells that are capable of reaching the brain to transport the drug. For example, a particular mode of delivery includes the use of macrophages present in the patient's cerebrospinal fluid (CSF) to deliver drugs to the brain. This process requires that the pharmaceutical composition be in a particle form that readily allows the macrophage to ingest it by means of phagocytosis. There are numerous advantages in the delivery of the drug to the brain by means of macrophages through oral ingestion. The load or amount of drug that can be delivered rises due to the high packing inherent to a particulate form that macrophages can phagocytose. Because the drug is being administered to the CSF, the hepatic metabolism is omitted because the drug is not exposed to circulation in the system with the consequent supply to the liver. Once the drug is administered in the CSF, it can persist as an extended-release depot for weeks or months. In the form of particles, the drug is ingested by brain macrophages that produce sanctuaries for viral bacterial diseases such as the human immunodeficiency virus (HIV). Because the drug is concentrated in the macrophages of the brain, the infectious organism is exposed to much larger amounts of the drug thus killing the organism. Macrophages can pass through the cerebrospinal fluid-brain barrier into the brain and release drug concentrations in the brain due to the dissolution of the particle within the macrophages. As a result, free viral and bacterial organisms resident in the brain at concentrations greater than what can typically be administered by means of oral administration. The brain is able to eliminate more rapidly the microbial organisms thus preventing the emergence of organisms resistant to the drug. In addition, the subsequent implantation and perpetuation of the organism causing the disease within the body can be mitigated. Administration of the drug in this manner allows for the greater use of the drug within the brain while allowing lower drug levels to be used. Excessive hepatic metabolism of drugs can be avoided and the cost of therapy can be reduced by this invention. There is a need, therefore, for nanosuspension compositions of anti-retroviral agents and methods for their manufacture, capable of being delivered to the brain. SUMMARY OF THE INVENTION The present invention provides compositions that They consist of nanosuspensions of anti-retroviral agents and manufacturing methods. The nanosuspensiones are produced through the process of microprecipitación and addition of energy. Preferably, the nanosuspensions are produced by the tandem microprecipitation-homogenization process. The nanosuspensions of the present invention can provide an anti-retroviral agent to the brain of a mammalian subject by means of cellular transport. The composition can be used to provide the anti-retroviral agent to the brain to treat an HIV infection. In a preferred embodiment, the process includes the steps of: (i) isolating cells from the mammalian subject, (ii) contacting the cells with a nanosuspension of anti-retroviral agent (s) particles having an average particle size of from about 100 nm to about 100 microns / preferably about 1 00 nm about 8 microns), (iii) allowing sufficient time for cells to absorb the particles , and (iv) administering to the mammal the loaded cells to deliver a portion of the pharmaceutical composition to the brain. There are numerous types of cells in mammals that are capable of this cellular absorption and transport of particles. These cells include but are not limited to T lymphocytes, macrophages, monocytes, granulocytes, neutrophils, basophils, and eosinophils. The method can be used to deliver the anti-retroviral agent to the brain to treat infection by VI H. BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows the results of the stress tests of the Indinavir nanosuspension using tests designed to determine the stability long-term formulation. Figure 2 shows the long-term stability data for the nanosuspension of Indinavir produced using high pressure homogenization. DETAILED DESCRIPTION OF THE INVENTION The present invention is susceptible to being carried out in different ways. Preferred embodiments of the invention are described with the understanding that the present disclosure should be considered as an exemplification of the principles of the invention and is not intended to limit the broader aspects of the invention to the illustrated embodiments.

The present invention provides compositions containing dispersions of anti-retroviral agents and methods of manufacture. Dispersions or nanosuspensions are carried out by means of the microprecipitation and energy addition process. Preferably, the nanosuspensions are carried out by means of the tandem microprecipitation-homogenization process. The anti-retroviral agent in those processes can be a protease inhibitor, a nucleoside reverse transcriptase inhibitor, or a non-nucleoside reverse transcriptase inhibitor. Examples of protease inhibitor include but are not limited to indinavir, ritonavir, saquinavir, and nelfinavir. Examples of nucleoside reverse transcriptase inhibitors include but are not limited to zidovudine, didanosine, stavudine, zalcitabine and lamivudine. Examples of non-nucleoside reverse transcriptase inhibitors include but are not limited to nevirapine and delaviradine. The present invention provides a method for delivering a pharmaceutical composition to the brain of a mammal by means of cellular transport. The following description of the pharmaceutical composition is applied to all embodiments of the invention. The pharmaceutical composition may be poorly soluble in water or soluble in water. The pharmaceutical composition can also be a therapeutic agent or a diagnostic agent. The therapeutic agents may include any compound that is used to treat disorders of the central nervous system or diseases or disorders of the brain. The disorders of the central nervous system can be Parkinson's disease, Alzheimer's, cancer, viral infections, fungal infections, bacterial infections and spongiform encephalopathy. The pharmaceutical composition may further include a surfactant to stabilize the pharmaceutical composition. The surfactant can be selected from a variety of known anionic surfactants, cationic surfactants, nonionic surfactants and surface active biological modifiers. Preferably, the pharmaceutical composition is a poorly soluble compound in water. What is meant by "sparingly soluble in water" is a solubility of the compound in water of less than about 10 mg / ml, and preferably less than 1 mg / ml. These sparingly soluble compounds are more suitable for aqueous suspension preparations since there are limited alternatives for formulating these compounds in an aqueous medium. The following description of the particles also applies to all embodiments of the present invention. The particles in the dispersion can be amorphous, semi-crystalline, crystalline or a combination thereof determined by means of XRD. Prior to administration, the pharmaceutical composition can be homogenized by means of a homogenization process. The pharmaceutical composition can also be homogenized by means of a microprecipitation / homogenization process. The dispersion of the pharmaceutical composition can be sterilized before administration. Sterilization can be performed by means of any medical sterilization process including thermal sterilization or sterilization by means of gamma radiation. The present invention can be practiced with water soluble compounds. These water-soluble active compounds are trapped in a solid carrier matrix (for example polylactate-polyglycollate copolymer, albumin, starch) or encapsulated in a vesicle which is impermeable to the pharmaceutical compound. This encapsulating vesicle can be a polymeric coating such as a polyacrylate. In addition, the small particles prepared from these water-soluble compounds can be modified to improve the chemical stability and control the pharmacokinetic properties of the compounds to control the release of the compounds from the particles. Examples of water soluble compounds include but are not limited to simple organic compounds, proteins, peptides, nucleotides, oligonucleotides and carbohydrates. The particles used in the present invention have an effective particle size of generally from about 100 nm to about 100 μm, preferably from about 100 nm to about 8 microns, and more preferably from about 1 00 nm to about 400 nm, as measured by of dynamic light scattering methods, for example, photo-correlation spectroscopy, laser diffraction, low-angle laser light scattering (LALLS), mid-angle laser light scattering (MALLS), light obscuration methods (Coulter method, example), rheology, or microscope (light or electronic). The effective particle size per Preferred medium depends on factors such as the intended route of administration, formulation, solubility, toxicity and bioavailability of the compound. A. Preparation of the pharmaceutical composition as particles The processes for preparing the particles used in the present invention can be accomplished by means of numerous techniques known to those skilled in the art. The following is a representative but not exhaustive discussion of the techniques for preparing the dispersions of particles of pharmaceutical compositions. I. Energy addition techniques for forming small particle dispersions In general, the method for preparing small particle dispersions using energy addition techniques includes the step of adding the pharmaceutically active compound, which can sometimes be referred to as a drug, in a form in bulk to a suitable vehicle such as water or a water-based solution containing one or more of the surfactants indicated below, or another liquid in which the pharmaceutical compound is not appreciably soluble, to form a first suspension. Energy is added to the first suspension to form a particle dispersion. The energy is added by means of mechanical grinding, ground with pearls, ground with balls, ground with a hammer, ground with fluid energy or wet ground. These techniques are described in U.S. Pat. No. 5, 145,684, which is incorporated as a reference and forms part of it. Energy addition techniques also include submitting the first suspension at high tear conditions including cavitation, tear or impact forces using a microfluidizer. The present invention further contemplates adding energy to the first suspension using a piston space homogenizer or a countercurrent flow homogenizer such as that described in U.S. Pat. 5,091, 188 which is incorporated as a reference and forms part of it. Suitable piston space homogenizers are commercially available under the product name EMULSIFLEX by Avestin, and French Pressure Cells sold by Spectronic Instruments. Suitable microfluidizers are available from Microfluidics Corp. The step of adding energy can also be performed using sonification techniques. The phase Sonification can be done with a suitable device such as the Branson model S-450A or Cole-Parmer 500/750 Watt Model. These devices are well known in the industry. Typically the sonification device has a sonification horn or probe which is inserted into the first suspension to emit sonic energy in the solution. The sonification device in a preferred form of the invention operates at a frequency of from about 1 kHz to about 90 KHz and more preferably from about 20 kHz to 40 KHz or any range or combination of ranges. Probe sizes may vary and preferably in different sizes such as 1 inch or% inch or the like. Regardless of the energy addition technique used, the dispersion of small particles must be sterilized before use. Sterilization can be achieved using the high pressure sterilization techniques described below II. Precipitation methods for preparing dispersions of submicron sized particles Small particle dispersions can also be prepared by well known precipitation techniques. The following is a description of examples of precipitation techniques. Microprecipitation Methods An example of a microprecipitation method is described in U.S. Pat. 5,780,062, which is incorporated as a reference and forms part of it. The 062 patent describes a process for precipitating organic compounds that includes: (i) dissolving the organic compound in a first water-miscible solvent; (ii) preparing a polymer solution and an amphiphile in a second aqueous solvent and in that second aqueous solvent the organic compound is substantially insoluble whereby a polymer / amphiphile complex is formed; and (iii) mixing the solutions of steps (i) and (ii) to cause precipitation of an aggregate of the organic compound and the polymer / amphiphile complex. Another example of a precipitation process is described in co-pending US applications and assigned to us. of series 09 / 874,499; 09 / 874,799; 09 / 874,637; and 10/021, 692, which are incorporated by reference and form part of it. The processes described include the steps of: (1) dissolving an organic compound in a first water miscible organic solvent to create a first solution; (2) Mix the first solution with a second solvent or water to precipitate the organic compound to create a first suspension; and (3) adding energy to the first suspension in the form of high tearing or heat mixing to provide a dispersion of small particles. One or more optional surface modifiers indicated below can be added to the first organic solvent or to the second aqueous solution. Emulsion precipitation methods A suitable emulsion precipitation technique is described in the co-pending US application and assigned in common no. series 09 / 964,273, which is incorporated as a reference and forms part of it. In this method, the process includes the steps of: (1) providing a system of multiple aces having an organic phase and an aqueous phase, the organic phase having a pharmaceutically active compound; and (2) sonicate the system to evaporate a portion of the organic phase to cause precipitation of the compound in the aqueous phase to form a dispersion of small particles. The step of providing a multi-phase system includes the steps of: (1) mixing a water-immiscible solvent with the pharmaceutically active compound to define an organic solution, (2) preparing a water-based solution with one or more active compounds on the surface, and (3) mixing the solution with the aqueous solution to form the multi-phase system. The step of mixing the organic phase and the aqueous phase can include piston space homogenizers, colloid mills, high speed agitation equipment, extrusion equipment, manual agitation or stirring equipment, microfluidizer and other equipment or techniques to provide high tear conditions. The crude emulsion will have water droplets in the water of a size of approximately less than 1 μm in diameter. The crude emulsion is sonified to define a microemulsion and eventually provide a dispersion of small particles. Another method for preparing a dispersion of small particles is described in the co-pending US application and assigned in common no. of series 10/1 83,035, which is incorporated as a reference and forms part of it. The process includes the steps of: (1) providing a dispersion of a multiphase system having an organic phase and an aqueous phase, the organic phase having a pharmaceutical compound; (2) providing energy to the raw dispersion to form a fine dispersion; (3) freeze the fine dispersion; and (4) lyophilizing the fine dispersion to obtain small particles of the pharmaceutical compound. The small particles can be sterilized by the techniques indicated below or the small particles can be reconstituted in an aqueous medium and sterilized. The step of providing a multi-phase system includes the steps of: (1) mixing a water immiscible solvent with the pharmaceutically effective compound to define an organic solution; (2) preparing a water-based solution with one or more active compounds on the surface; and (3) mixing the organic solution with the aqueous solution to form the multiphase system. The step of mixing the organic phase and the aqueous phase includes the use of piston space homogenizers, colloidal mills, high speed agitation equipment, equipment of extrusion, manual agitation or agitation equipment, microfluidizer and other equipment or techniques to provide high tear conditions. Precipitation of anti-solvent solvent The dispersions of small particles can also be prepared by means of the solvent-solvent precipitation technique described in US Pat. 5, 1 18,528 and 4,100,591 that are incorporated by reference and form part of it. The process includes the steps of: (1) preparing a liquid phase of a biologically active substance in a solvent or solvent mixture to which one or more surfactants may be added; (2) prepare a second liquid phase of a non-solvent or a mixture of non-solvents, the non-solvent can be mixed with the solvent or mixture of solvents for the substance; (3) join the solutions (1) and (2) with agitation; and (4) removing unwanted solvents to produce a dispersion of small particles. Precipitation by phase inversion Dispersions of small particles can be formed using the phase inversion precipitation as described in US Pat. 6,235,224, 6, 143, 211 and U.S. patent application no. 2001/0042932, each of which are incorporated as a reference and form part of it. Phase inversion is a term used to describe the physical phenomenon by means of which a polymer dissolved in a solvent system in a continuous phase is inverted in a solid macromolecular network in which the polymer is in a continuous phase. One method to induce phase inversion is by means of the addition of a non-solvent to the continuous phase. The polymer undergoes a transition from a single phase to an unstable two-phase mixture: the polymer-rich and low-polymer fractions. The miscellaneous droplets of non-solvent in the polymer-rich phase serve as nucleation sites and are coated with the polymer. The '224 patent discloses that the reversal and phases of the polymer solutions under certain conditions can cause the spontaneous formation of microparticles including nanoparticles. The '224 patent describes dissolving or dispersing a polymer in a solvent. A pharmaceutical agent also dissolves or disperses in the solvent. For the stage of planting the crystal to be effective in this process it is desirable that the agent be dissolved in the solvent. The polymer, the agent and the solvent together form a mixture having a continuous phase, wherein the solvent is in the continuous phase. The mixture is then introduced to an excess of at least ten times the miscible non-solvent to cause the spontaneous formation of the microencapsulated microparticles of the agent having an average particle size of between 10 nm and 10 μm. The particle size is influenced by the volumetric solvent ratio: non-solvent, the concentration of the polymer, the viscosity of the polymer-solvent solution, the molecular weight of the polymer and the characteristics of the solvent-non-solvent pair. Precipitation by pH modification Dispersions of small particles can be formed by precipitation techniques by pH modification. Those techniques typically include a step of dissolving a drug in a solution that have a pH at which the drug is soluble, followed by the step of changing the pH to a point where the drug is no longer soluble. The pH can be acidic or basic, depending on the particular pharmaceutical compound. The solution is then neutralized to form a dispersion of small particles. A precipitation process by suitable pH modification is described in U.S. Pat. 5,665,331, which is incorporated as a reference and forms part of it. The process includes the step of dissolving the pharmaceutical agent together with a crystalline growth modifier (CGM) in an alkaline solution and then neutralizing the solution with an acid in the presence of one or more suitable surfactant surface modifying agents to form a dispersion. of small particles of the pharmaceutical agent. The precipitation step can be followed by cleaning steps by diafiltration of the dispersion and then adjusting the concentration of the dispersion to a desired level. Other examples of precipitation methods by pH modification are described in US Pat. 5,716,642; 5,662,883; 5,560,932 and 4,608,278, which are incorporated by reference and form part of it. Infusion Precipitation Method Suitable infusion precipitation techniques to form small particle dispersions are described in US Pat. 4,997,454 and 4,826,689 that are incorporated by reference and form part of it. First a suitable solid compound is dissolved in a suitable organic solvent to form a solvent mixture. Then a non-precipitated solvent miscible with the organic solvent is infused into the solvent mixture at a temperature between about -10 ° C and about 100 ° C and at an infusion rate of about 0.1 ml per minute to about 100 ml per minute per volume of 50 ml to produce a suspension of precipitated non-aggregated solid particles of the compound with a substantially uniform average size of less than 10 μm. The stirring (for example by stirring) of the solution being infused with the precipitating non-solvent is preferred. The non-solvent may contain a surfactant to stabilize the particles against aggregation. The particles are then separated from the solvent. Depending on the solid compound and then the desired particle size, the temperature parameters, ratio of non-solvent to solvent, infusion rate, agitation rate and volume may vary according to the invention. The particle size is proportional to the ratio of volumes of non-solvent: solvent and the temperature of the infusion and is inversely proportional to the rate of infusion and agitation. The non-precipitating solvent may be aqueous or non-aqueous, depending on the relative solubility of the compound and the desired suspension vehicle. Precipitation by temperature modification Precipitation techniques by temperature modification can also be used to form dispersions of small particles. That technique is described in the North American patent no. 5, 188, 837 that is incorporated as a reference and forms part of it. In one embodiment of the invention, lipospheres are prepared by the steps of (1) fusing or dissolving a substance such as a drug that goes to be supplied, in a molten vehicle to form a liquid of the substance to be delivered; (2) adding a phospholipid together with an aqueous medium to the molten substance or vehicle at a temperature higher than the melting temperature of the substance or vehicle; (3) mixing the suspension at a temperature above the melting temperature of the vehicle until a homogeneous fine preparation is obtained; and then (4) quickly cool the preparation to room temperature or below it. Precipitation by evaporation of the solvent The techniques of precipitation by evaporation of the solvent are described in the North American patent no. 4,973,465 that is incorporated as a reference and forms part of it. The '465 patent describes methods for preparing microcrystals including the steps of (1) providing a solution of a pharmaceutical composition and a phospholipid dissolved in a common organic solvent or combination of solvents, (2) evaporating the solvent (s) and (3) suspending the film obtained by evaporating the solvent (s) in an aqueous solution by stirring vigorously to form a dispersion of small particles. The solvent can be removed by adding energy to the solution to evaporate a sufficient amount of the solvent to cause precipitation of the compound. The solvent can also be removed by other well-known techniques such as applying a vacuum to the solution or blowing nitrogen onto the solution. Precipitation by reaction Reaction precipitation includes the steps of dissolving the pharmaceutical compound in a suitable solvent to form a solution. The compound must be added in an amount of or below the saturation point of the compound in the solvent. The compound is modified by reacting with a chemical agent or by modification in response to the addition of energy such as heat or UV light or the like in such a way that the modified compound has a lower solubility in the solvent and is precipitated from the solution to form a small particle dispersion. Precipitation by compressed fluid A suitable technique for precipitating by means of compressed fluid is described in WO 97/14407 of Johnston, which is incorporated by reference and forms part thereof. The method includes the steps of dissolving a water-insoluble drug in a solvent to form a solution. The solution is then sprayed in a compressed fluid that can be a gas, liquid or supercritical fluid. The addition of the compressed fluid to a solution of a solute in a solvent causes the solute to obtain or approach the supersaturated state and to precipitate in the form of fine particles. In this case the compressed fluid acts as an antisolvent that reduces the cohesion energy density of the solvent in which the drug dissolves. Alternatively, the drug can be dissolved in the compressed fluid which is then sprayed in an aqueous paste. The rapid expansion of the compressed fluid reduces the solvent power of the fluid, which in turn causes the solute to precipitate in the form of small particles in the aqueous paste. In this case, the compressed fluid acts as a solvent.

In order to stabilize the particles against aggregation, a surface modifier such as a surfactant is included in this technique. Precipitation of protein microspheres The microspheres or microparticles used in this invention can also be produced with a process that includes mixing or dissolving macromolecules such as proteins with a water-soluble polymer. This process is described in US Pat. Nos. 5,849,884, 4981, 71 9, 6,090,925, 6,268,053, 6458,387 and the North American provisional application no. 60 / 244,098, which are incorporated as a reference and form part of it. In one embodiment of the invention, the microspheres are prepared by mixing a macromolecule in solution with a polymer or a mixture of polymers in a solution at a pH near the isoelectric point of the macromolecule. The mixture is incubated in the presence of an energy source, such as heat, radiation or ionization, for a predetermined time of time. The resulting microspheres can be removed from any unincorporated component present in the solution by physical separation methods. There are numerous additional methodologies for preparing small particle dispersions. The present invention provides a methodology for terminally sterilizing those dispersions without significantly reducing the effectiveness of the preparation, III. Additional methods for preparing particle dispersions of pharmaceutical compositions The following additional processes for preparing particles of pharmaceutical compositions (for example organic compounds) used in the present invention can be separated into four general categories. Each of the process categories share the steps of: (1) dissolving an organic compound in a first water miscible organic solvent to create a first solution; (2) mixing the first solution with a second solvent or water to precipitate the organic compound to create a pre-suspension; and (3) adding energy to the first suspension in the form of high tear or heat mixing to provide a stable form of an organic compound having the desired sizes defined above. The mixing steps and the stage of adding energy can be carried out in consecutive stages or simultaneously. The categories of the processes are distinguished based on the properties of the organic compound determined by means of x-ray diffraction studies, differential scanning calorimetry (DSC) studies or other suitable studies conducted before the energy addition stage and after the energy addition stage. In the first process category, before the energy addition step the organic compound in the first suspension takes an amorphous form, a semi-crystalline form or a super cold liquid and has an average effective particle size. After the energy addition step the organic compound is in a crystalline form having an average effective particle size essentially equal to or less than that of the first suspension. In the second process category, before the energy addition stage the organic compound is in a form crystalline and has an average effective particle size. After the energy addition step the organic compound has a crystalline form which has essentially the same average effective particle size as before the energy addition stage but the crystals after the energy addition stage tend less to aggregate. The low tendency of the organic compound to be added is observed by means of dynamic laser light scattering and light microscope. In the third process category, before the energy addition step the compound has a crystalline form which is friable and has an average effective particle size. What is meant by the term "friable" is that the particles are brittle and break more easily into smaller particles. After the energy addition step the compound is in a crystalline form having an average effective particle size smaller than the crystals of the pre-suspension. By taking the steps necessary to place the organic compounds in a crystalline form that is friable, the subsequent energy addition step can be carried out more quickly and efficiently when compared with an organic compound in a less friable crystalline morphology. In a fourth process category, the first solution and the second solvent are simultaneously subjected to the energy addition stage. Thus the physical properties of the organic compound before and after the energy addition step were not measured. The energy addition stage can be performed from any in which the first or first solution suspension and the second solvent are exposed to cavitation, tear or impact forces. In a preferred form, the energy addition step is a thermal fixing step. Thermal fixation is defined in this invention as the process of converting material that is thermodynamically unstable into a more stable form by means of the single or repeated application of energy (direct heat or mechanical stress), followed by thermal relaxation. This energy reduction can be obtained by converting the solid form to a less ordered one to a more ordered network structure. Alternatively, this stabilization can occur by rearranging the surfactant molecules in a solid-liquid interface. Those four process categories are shown separately below. It should be understood, however, that process conditions such as the selection of surfactants or combination of surfactants, the amount of surfactant used, the reaction temperature, the mixing rate of the solutions, the precipitation rate and the like can be selected to allow Any drug is processed under any of the categories described below. The first process category, as well as the second, the third and the fourth process category, can further be divided into two subcategories, Method A and B. The first solvent according to the following processes is a solvent or mixture of solvents in the which organic compound of interest is relatively soluble and which is miscible with the second solvent. These solvents include, but are not limited to, miscible protic compounds in water, in which the hydrogen atom in the molecule is linked to an electronegative atom such as oxygen, nitrogen or another group VA, VIA and VIIA in the periodic table of the elements. Examples of such solvents include but are not limited to alcohols, amines (primary or secondary), oximes, hydroxamic acids, carboxylic acids, sulfonic acids, phosphonic acids, phosphoric acids, amides and ureas. Other examples of the first solvent also include aprotic organic solvents. Some of these aprotic solvents can form hydrogen bonds with water, but they can only act as proton acceptors because they lack effective proton donor groups. One class of aprotic solvents is a dipolar aprotic solvent, defined by the International Union of Pure and Applied Chemistry (I UPAC Compendium of Chemical Terminology, 2nd edition, 1997): A solvent with a comparatively high permittivity (or dielectric constant) greater than about 15, your measurable permanent dipole moment that can not donate suitable labile hydrogens atoms to form strong hydrogen bonds, for example dimethyl sulfoxide. The dipolar aprotic solvents can be selected from the group consisting of: amides (completely substituted with nitrogen without linked hydrogen atoms), ureas (completely substituted without hydrogen atoms bonded to nitrogen), ethers, cyclic ethers, nitriles, ketones, sulfones, sulfoxides, completely substituted phosphates, phosphonate esters, phosphoramides, nitro compounds and the like. Dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidinone 8NMP), 2-pyrrolidinone, 1, 3- dimethyl imidazolidinone (DMI), dimethylacetamide (DMA), dimethylformamide (DMF), dioxane, acetone, tetrahydrofuran (THF), tetramethylenesulfone (Sulfolane), acetonitrile and hexamethylphosphoramide (HMPA), nitromethane, among others, are members of this class. Solvents may also be selected that are generally immiscible in water, but have sufficient water solubility at low volumes (less than 10%) to act as a first solvent miscible in water at those reduced volumes. Examples include aromatic hydrocarbons, alkenes, alkanes, and halogenated aromatics, halogenated alkenes and halogenated alkanes. Aromatics include but are not limited to benzene (substituted or o), and monocyclic or polycyclic lows. Examples of substituted benzenes include but are not limited to xylenes (ortho, meta or para) and toluene. Examples of alkanes include but are not limited to hexane, neopentane, heptane, isooctane and cyclohexane. Examples of halogenated aromatics include but are not restricted to chlorobenzene, bromobenzene and chlorotoluene. Examples of halogenated alkanes and alkenes include but are not restricted to, trichloroethane, methylene chloride, ethylene dichloride (EDC) and the like. Examples of all of the above solvent classes include but are not limited to: N-methyl-2-purrolidinone (also called N-methyl-2-pyrrolidone), 2-pyrrolidinone (also called 2-pyrrolidone), 1,3-dimethyl -2-imidazolidinone (DMI), dimethyl sulfoxide, dimethylacetamide, acetic acid, lactic acid, methanol, ethanol, isopropanol, 3-pentnaol, n-propanol, benzyl alcohol, glycerol, butylene glycol (bitanodiol), ethylene glycol, propylene glycol, monoglycerides mono - and diacylates (such as caprylate Glyceryl), dimethyl isosorbide, acetone, dimetilsulfonam dimethylformamide, 1, 4-dioxane, tetramethylenesulfone (sulfolane), acetonitrile, nitromethane, tetramethylurea, hexamethylphosphoramide (HMPA), tetrahydrofuran (THF), dioxane, diethylether, ether tert-butilmeitlo (TBME), aromatic hydrocarbons, alkenes, alkanes, halogenated aromatics, halogenated alkenes, alkanes halogenated, xylene, toluene, benzene, substituted benzene, ethyl acetate, methyl acetate, butyl acetate, chlorobenzene, bromobenzene, chlorotoluene, trichloroethane, chloride of methylene, ethylene dichloride (EDC), hexane, neopenthane, heptane, isocotan, cyclohexane, polyethylene glycol (PEG, for example PEG-4, PEG-8, PEG-9, PEG-12, PEG-14, PEG-16, PEG-120, PEG-75, PEG-150), polyethylene glycol esters (examples such as PEG-4 dilaurate, PEG-20 dilaurate, PEG-6 isostearate, PEG-8 palmisostearate, PEG-150 palmito-stearate) , sorbitans of polyethylene glycol (such as sorbitan isostearate) PEG-20), monoalkyl ethers poiietilenglicol (examples such as dimethyl ether, PEG-3 dimethyl ether, PEG-4), polypropylene glycol (PPG), alginate polypropylene, butanediol, PEG-10, ether methyl glucose of PEG-10, methyl glucose ether of PEG-20, stearyl ether PEG-15. propylene glycol dicapirlate / dicaprate, propylene glycol laurate, and glycofurol (polyethylene glycol ester of tetrahydrofurfuryl alcohol). A first preferred solvent is N-methyl-2-pyrrolidinone. Another preferred first solvent is lactic acid. The second solvent is an aqueous solvent. This aqueous solvent can be water by itself. This solvent may also contain buffers, salts, surfactant (s), water soluble polymers, and combinations of these excipients. Method A In method A (see figure 1), the organic compound ("drug") is first dissolved in the first solvent to create a first solution. The organic compound can be added from about 0.1% (w / v) to about 50% (w / v) depending on the solubility of the organic compound in the first solvent. Heating the concentrate to from about 30 ° C to 100 ° C may be necessary to ensure complete dissolution of the compound in the first solvent. A second aqueous solvent is provided with one or more optional surface modifiers such as an anionic surfactant, a cationic surfactant, a nonionic surfactant or a biologically active molecule on the aggregate surface. Anionic surfactants include but are not limited to alkyl sulfonates, alkyl phosphates, alkyl phosphonates, potassium laurate, stearate etietanolamina, sodium lauryl sulfate, sodium dodecylsulfonate, polyoxyethylene sulfates, alkyl sodium alginate, dioctyl dioctyl sodium, phosphatidyl choline, glycerol phosphatidyl, ionisina phosphatidyl, fosftidilserina, phosphatidic acid and their salts, glyceryl esters, sodium carboxymethylcellulose, cholic acid and other bile acids (for example cholic acid, deoxycholic acid, glycocholic acid, taurocholic, glycodeoxycholic acid) and its salts (for example sodium deoxycholate, etc.). Suitable cationic surfactants include but are not limited to quaternary ammonium compounds, such as benzalkonium, cetyltrimethylammonium bromide, chitosans, lauryldimethylbenzylammonium chloride, acyl carnitine hydrochlorides, or alkyl pyridinium halides. Phospholipids can be used as anionic surfactants. Suitable phospholipids include, for example phosphatidylcholine, phosphatidylethanolamine, diacylglycero-phosphoethanolamine (such as dimyristoyl-glycero-phosphoethanolamine (DMPE), dipalmitoyl-glycero-phosphoethanolamine (DPPE), diesteroaroil-glycero-phosphoethanolamine (DSPE), dioleoyl-glycero-phosphoethanolamine (DOPE )), dosphatidylserine, phosphatidylinositol, phosphatidylglycerol, phosphatidic acid, lysoprophopholipids, egg or soy phospholipids or a combination thereof. The phospholipid can be salified or not, hydrogenated or partially hydrogenated or natural, semi-synthetic or synthetic. The phospholipid can also be conjugated with a water soluble or hydrophilic polymer. A preferred polymer is polyethylene glycol (PEG), which is also known as monomethoxy polyethylene glycol (mPEG) knob. The molecular weights of PEG can vary, for example, from 200 to 50,000. Some commonly used PEGs that are commercially available include PEG 350, PEG 550, PEG 750, PEG 1000, PEG 2000, PEG 3000 and PEG 5000. The phospholipid or the PEG-phospholipid conjugate can also incorporate a functional group that can be covalently linked to a ligand that includes but is not limited to proteins, peptides, carbohydrates, glycoproteins, antibodies, or pharmaceutically active agents. These functional groups can be conjugated to the ligands by means of, for example, the formation of amide bonds, the formation of disulfide or thioether, or the biotin / streptavidin linkage. Examples of the ligand-link functional groups include but are not limited to hexanoylamine, dodecamylamine, 1,2-dodecanediarboxylate, thioethanol, 4- (p-maelimidophenyl) butyrate (MPB), 4- (p-maleimidomethyl) cyclohexane-carboxamide (MCC), 3- (2-pyridyldithio ) propionate (PDP), succinate, glutarate, dodecanoate and biotin. Suitable nonionic surfactants include: polyoxyethylene fatty alcohol ethers (Macrogol and Brij), polyoxyethylene sorbitan fatty acid esters (polysorbates), polyoxyethylene fatty acid esters (Myrj), sorbitan esters (Span), glycerol monostearate polyethylene glycols, polypropylene glycol, cetyl alcohol, keto stearyl alcohol, stearyl alcohol, aryl alkyl polyether alcohols, polyoxyethylene-polyoxypropylene copolymers (poloxamers), poloxamines, methyl cellulose, hydroxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, non-crystalline cellulose, polysaccharides including starch and derivatives of starch such as hydroxyalmidon (HES), polyvinyl alcohol, and polyvinylpyrrolidone. In a preferred form, the nonionic surfactant is a copolymer of polyoxyethylene and polyoxypropylene and preferably a block copolymer of propylene glycol and ethylene glycol. These polymers are sold under the tradename POLOXAMER also called PLURONIC®, sold by several suppliers including Spectrum Chemical and Ruger. The polyoxyethylene fatty acid ethers include those having short alkyl chains. An example of such a surfactant is SOLUTOL® HS 15, polyethylene-660 hydroxystearate, manufactured by BASF Aktiengesellschaft. The biological molecules active on the surface include molecules such as albumin, casein, hirudin or other appropriate proteins. Biological polysaccharides are also included and consist but are not limited to starches, heparin and chitosans. It may also be desirable to add an agent that adjusts the pH to the second solvent such as sodium hydroxide, hydrochloric acid, tris or citrate buffer, acetate, lactate, meglumine or the like. The second solvent should have a pH in the range of about 3 to about 1 1. For oral dosage forms, one or more of the following excipients may be used: gelatin, casein, lecithin (phosphatides), acacia gum, cholesterol. tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glyceryl monostearate, keto stearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, for example macrogol ethers such as cetomacrogol 1000, polyoxyethylene resin oil derivatives, esters of polyoxyethylene sorbitan fatty acids, for example commercially available Tweens®, polyethylene glycols, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecylisulfate, calcium carboxymethylcellulose, sodium carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose phthalate , non-crystalline cellulose, magnesium aluminum silicate, triethanolamine, polyvinyl alcohol. (PVA) and polyvinylpyrrolidone (PVP). Most of these excipients are described in detail in the Handbook of Pharmaceutical Excipients, published jointly by the American Pharmaceutical Association and The Pharmaceutical Society of Great Britain, the Pharmacutical Press, 1986. Surface modifiers are commercially available and / or can be prepared by techniques known in the art. Two or more surface modifiers can be used in combination. In a preferred form, the method for preparing small particles of an organic compound includes the steps of adding the first solution to the second solvent. The rate of addition depends on the size of the batch, and the kinetics of preparation of the organic compound. Typically for a small-scale laboratory process (1 liter preparation), the addition rate is from about 0.05 ce per minute to about 10 ce per minute. During the addition, the solutions must be under constant agitation. It has been observed using light microscopy that amorphous particles, semi-crystalline solids, or a super cold liquid are formed to create a pre-suspension. The method further includes the step of subjecting the presuspension to an energy addition step to convert amorphous particles, super cold liquid or semicrystalline solid to a more stable crystalline solid state. The resulting particles will have an average effective particle size measured by means of dynamic light scattering methods (e.g., photo-correlation spectroscopy, laser diffraction, low-angle laser light scattering (LALLS), mid-angle laser light scattering (MALLS). ), methods of obscuration of light (Coulter method, for example), rheology, or microscope (luminous or electronic) within the ranges indicated above). In the process four category, the first solution and the second solvent combine while driving simultaneously the energy addition stage. The energy addition step includes adding energy by means of sonification, homogenization, countercurrent flow homogenization, microfluidization, or other methods to provide impact, tear or cavitation forces. The sample may be cooled or heated during this stage. In a preferred form, the energy addition step is effected by means of a piston space homogenizer, such as sold by Avestin Inc. under the designation of the product EmulsiFlex-C160. In another preferred form, the energy addition step can be achieved by means of ultrasound using an ultrasonic processor such as the Vibra-Cell Uitrasonic Processor (600W), manufactured by Sonics and Materials, Inc. In another preferred form, the step of addition of energy can be achieved through the use of an emulsification apparatus described in the North American patent or. 5,720,551 which is incorporated as a reference and forms part of it. Depending on the rate of energy addition, it may be desirable to adjust the temperature of the processed sample within the range of about -30 ° C to 30 ° C. Alternatively in order to effect the desired phase change in the processed solid , it may also be necessary to heat the pre-suspension to a temperature within the range of about 30 ° C to 100 ° C during the energy addition stage. Method B Method B differs from method A in the following aspects. The first difference is that a surfactant or combination is added of surfactants to the first solution. The surfactants can be selected from the groups of anionic, nonionic, cationic surfactants and biological surface active modifiers as indicated above. Comparative example of method A and method B and USPN 5,780,062 U.S. patent no. No. 5,780,062 describes a process for preparing small particles of an organic compound by first dissolving the compound in a suitable first solvent miscible with water. A second solution is prepared by dissolving a polymer and an amphiphile in an aqueous solvent. The first solution is then added to the second solution to form a precipitate consisting of the organic compound and the polymer-amphiphile complex. The '062 patent does not disclose the use of the energy addition step of this process in Methods a and B. The lack of stability is typically evidenced by rapid aggregation and particle growth. In some cases, the amorphous particles recrystallize as large crystals. The addition of energy to the pre-suspension in the manner described above typically produces particles that show lower rates of particle aggregation and growth as well as the absence of recrystallization after storage of the product. Methods A and B are further distinguished from the process of the '062 patent by the absence of a polymer-amphiphilic complex formation step prior to precipitation. In method A, that complex can not be formed since no polymer is added to the (aqueous) solvent phase. In method B, the surfactant, which can also act as an amphiphile, or polymer, is dissolved with the organic compound in the first solvent. This prevents the formation of any amphiphilic-polymer complex before precipitation. In the '062 patent, the successful precipitation of small particles is based on the formation of an amphiphilic-polymer complex prior to precipitation. The '062 patent discloses that the amphiphilic-polymer complex forms aggregates in the second aqueous solution. The '062 patent explains that the hydrophobic organic compound interacts with the amphiphilic-polymer complex, reducing the solubility of those aggregates and causing precipitation. In the present process it has been shown that the inclusion of the surfactant or polymer in the first solvent (method B), leads after the subsequent addition to the second solvent, to the formation of more uniform and fine particles than those produced by means of the process described in the '062 patent. For this purpose, two formulations were prepared and analyzed. Each of the formulations has two solutions, a concentrate and an aqueous diluent, which are mixed together and then sonified. The concentrate in each formulation has an organic compound (itraconazole), a solvent miscible in water (N-methyl-2-pyrrolidone or NMP) and possibly a polymer (poloxamer 1888). The aqueous diluent has water, a tris buffer and possibly a polymer (poloxamer 188) and / or a surfactant (sodium deoxycholate). The average particle diameter of the organic particle is measured before and after sonification. The first formulation A has itraconazole and NMP as a concentrate. The aqueous diluent includes water, poloxamer 188, tris buffer and sodium deoxycholate. Thus, the aqueous diluent includes a polymer (poloxamer 188), and an amphiphile (sodium deoxycholate), which can form a polymer / amphiphile complex, and therefore does not agree with the description of the '062 patent. However, we repeat the '062 patent does not disclose an energy addition step). The second formulation B has itraconazole, NMP and poloxamer 188 as a concentrate. The aqueous diluent includes water, poloxamer 188, tris buffer and sodium deoxycholate. This formulation is made according to the present process. Since the aqueous diluent does not contain a combination of a polymer (poloxamer) and an amphiphile (sodium deoxycholate), a polymer / amphiphile complex can not be formed before the mixing step. Table 1 shows the average particle diameters measured by laser diffraction in three replicate suspension preparations. A determination of the initial size is made, after which the sample is sonicated for 1 minute. The size determination was then repeated. The reduction of the large size after the sonification of method A indicated the aggregation of particles. Table 1 : A suspension of the drug resulting from the application of the processes can be administered directly as an injectable solution, providing that water for injection is used in the formulation and the appropriate means are applied for the sterilization of the solution. Sterilization can be achieved by methods well known in the art such as steam or heat sterilization, gamma radiation and the like. Other sterilization methods especially for particles in which more than 99% of the particles are less than 200 nm, would also include pre-filtering through a 3.0 micron filter followed by filtering through a 0.45 particle filter. microns, followed by sterilization with steam or heat or sterile filtration through two membrane filters of 0.2 microns redundant. Still another means of sterilization is the sterile filtrate of the concentrate prepared from the first drug containing solvent and surfactant or optional surfactants and sterile filtration of an aqueous diluent. These have been combined in a sterile mixing container, preferably in a sterile insulated medium. The mixing, homogenization and subsequent processing of the suspension are then carried out under aseptic conditions. Yet another method for sterilization would consist of thermal sterilization or autoclaving within the homogenizer itself, before, during or subsequent to the homogenization step. The processing after this heat treatment would be carried out under aseptic conditions. Optionally, a solvent-free suspension is will produce by means of solvent removal after precipitation. This can be achieved by means of centrifugation, dialysis, diafiltration, field strength fractionation, high pressure filtration, reverse osmosis, and other separation techniques well known in the art. The complete removal of N-methyl-2-pyrrolidinone was typically carried out by means of one to three successive centrifugation runs; after each centrifugation (1 8,000 rpm for 30 minutes) the cream is decanted and discarded. A fresh volume of the suspension vehicle without the organic solvent was added to the remaining solids and the mixture dispersed by means of homogenization. Those skilled in the art will recognize that other high tear mixing techniques could be applied in this reconstitution step. Alternatively, the solvent-free particles can be formulated in various dosage forms as desired for a variety of routes of administration, such as oral, pulmonary, nasal, topical, intramuscular, and the like. In addition, any undesirable excipients such as surfactants can be replaced by more desirable excipients by using the separation methods described in the preceding paragraph. The solvent and the first excipient can be discarded with the cream after centrifugation or filtration. A fresh volume of the suspension vehicle without the solvent and without the first excipient can then be added. Alternatively, a new surfactant can be added. For example a consistent suspension of a drug, N-methyl-2-pyrrolidinone (solvent), poloxamer 188 (first excipient), sodium dicoxycholate, glycerol and water can be replaced with phospholipids (new surfactant), glycerol and water after centrifugation and removal of the cream. I. First Process Category The methods of the first process category generally include the step of dissolving the organic compound in a first solvent miscible with water followed by the step of mixing this solution with an aqueous solvent to form a first suspension wherein the The organic compound is found in an amorphous form, a semicrystalline form or in a super cold liquid as determined by X-ray diffraction studies, DSC, light microscope and other analytical techniques and has an effective average particle size within one. of the effective particle size ranches indicated above. The mixing step is followed by a step of adding energy. I I. Second Process Category The methods of the second process category include essentially the same stages as in the stages of the first process category but differ in the following aspects. A X-ray diffraction, DSC or other suitable analytical techniques of the first suspension shows the organic compound in a crystalline form and having an effective average particle size. The organic compound after the energy addition step has essentially the same effective average particle size as before the energy addition stage but has a lower tendency to aggregate to form larger particles compared to the particles of the first suspension. Without wanting to adhere to a theory, it is believed that the differences in the stability of the particles may be due to the rearrangement of the molecules of the surfactant in the solid-liquid interface, l l l. Third Process Category The methods of the third process category modify the first two stages of the first and second process categories to ensure that the organic compound in the first suspension is in a friable form that has an effective average particle size ( as for example needles and thin plates). The friable particles can be formed by selecting the suitable solvents, surfactants or combination of surfactants, the temperature of the individual solutions, the mixing rate and the precipitation rate and the like. The friability can also be improved by introducing network defects (eg rupture planes) during the mixing steps of the first solution with the aqueous solvent. This would arise by means of rapid crystallization such as that required in the precipitation stage. In the energy addition stage those friable crystals are converted into crystals that are kinetically stabilized and have an effective average particle size smaller than those of the first suspension. Kinetically stabilized means that the particles have a reduced tendency to aggregate when compared to particles that are not kinetically stabilized. In these cases, the energy addition step results in the breaking up of friable particles. By ensuring that the particles of the first suspension are in a friable state, the organic compound can be prepared more easily and quickly into particles with the desired size ranges compared to the processing of the organic compound where they have not been taken. the steps to convert it to a friable form. IV. Fourth Process Category The methods of the fourth process category include the stages of the first process category except that the mixing step is performed simultaneously with the energy addition stage. Polymorphous Control The present process further provides additional steps to control the crystal structure of an organic compound to finally produce a suspension of the compound in the desired size range and a desired crystal structure. What the term "crystal structure" means is the arrangement of atoms within the unitary cell of the crystal. The compounds that can be crystallized in different crystal structures are said to be polymorphic. The identification of polymorphisms is an important step in the formulation of drugs since different polymorphisms of the same drug can show differences in solubility, therapeutic activity, bioavailability and stability of the suspension. Accordingly, it is important to control the polymorphic form of the compound to ensure the purity of the product and the reproducibility between batches. The steps to control the polymorphic form of the compound include implanting the first solution, the second solvent or the pre-suspension to ensure the formation of the desired polymorphism. The implementation includes using a seed compound or adding energy. In a preferred form the seed compound is a pharmaceutically active compound in the desired polymorphic form. Alternatively, the compoundPI.

Seed can also be an inert impurity, a compound not related in structure to the desired polymorphism but with characteristics that can lead to quench the nucleus of a crystal, or an organic compound with a structure similar to that of the desired polymorphism. The seed compound can be precipitated from the first solution. This method includes the steps of adding the organic compound in an amount sufficient to exceed the solubility of the organic compound in the first solvent to create a supersaturated solution. The supersaturated solution is treated to precipitate the organic compound in the desired polymorphic form. The treatment of the supersaturated solution includes aging the solution for a period of time until the formation of a crystal or crystals is observed to create the implantation mixture. It is also possible to add energy to the supersaturated solution to cause the organic compound to precipitate out of the solution in the form of the desired polymorphism. The energy can be added in a variety of ways including the energy addition stages described above. In addition, more energy can be added by heating or by exposing the pre-suspension to electromagnetic energy, or to a source of particle or electron beams. Electromagnetic energy includes light energy (ultraviolet, visible or infrared) or inherent radiation such as that provided by the laser, microwave energy such as that provided by a maser (microwave amplification by means of the stimulated emission of radiation), dynamic electromagnetic energy or other sources of radiation. It is also contemplated to use ultrasound, an electric field static, or a static magnetic field or combinations thereof as a source of energy addition. In a preferred form, the method for producing seed crystals from an aged supersaturated solution includes the steps of: (adding an amount of an organic compound to the first organic solvent to create a supersaturated solution, (ii) aging the supersaturated solution to form detectable crystals to create an implantation mixture, and (iii) mixing the implantation mixture with the second solvent to precipitate the organic compound to create a pre-suspension The first suspension can then be further processed as described in detail before to provide an aqueous suspension of the organic compound in the appropriate polymorphism and in the appropriate size range The implantation can also be carried out by adding energy to the first solution, the second solvent or the pre-suspension provided that the exposed liquid (s) contain the organic compound or a seed material.The energy can be added from the Same way described above for the supersaturated solution. Accordingly, the present process uses a material composition of an organic compound in a desired polymorphic form essentially free of the unspecified polymorphism or polymorphisms. In a preferred form, the organic compound is a pharmaceutically active substance. It is contemplated that the methods described herein may be used to selectively produce a desired polymorphism for numerous compounds pharmaceutically assets. B. Addressing the brain The compositions of the present invention are particularly useful for delivering anti-retroviral agents to the brain. Preferred methods for using the compositions of the present invention consist of the steps of: (i) providing a dispersion of pharmaceutically effective antiretroviral agent in particulate form, (ii) contacting the dispersion with the cells for cellular ingestion to form charged cells; and (iii) administering the loaded cells for delivery to the brain of a portion of the particles. The processes of drug delivery to the brain can be divided into ex vivo and in vivo categories depending on whether the dispersion contacts the cells outside or inside the mammal. The ex vivo process includes the steps of: (i) isolating cells from the mammal, (ii) contacting the cells with a nanosuspension of anti-retroviral agent (s) particles having an average particle size of about 1 00 nm to about 100 microns / preferably 100 nm about 8 microns), (iii) allow sufficient time for cells to absorb the particles, and (iv) administer to the mammal the loaded cells to deliver a portion of the pharmaceutical composition to the brain. There are numerous types of cells in mammals that are capable of this cellular absorption and transport of particles. These cells include but are not limited to T lymphocytes, macrophages, monocytes, granulocytes, neutrophils, basophils, and eosinophils. In addition, the particles in the size range of approximately 100 nm at 8 microns are more easily ingested by these phagocyte organisms. Isolation of mammalian macrophages can be done by means of a cell separator. For example, the Fenwal cell separator (Baxter Healthcare corp., Deefield, IL) can be used to isolate several cells. Once isolated, the particulate pharmaceutical composition contacts the isolated cell sample and is incubated for a short period of time to allow the cells to ingest the particles. It can take up to an hour to allow sufficient ingestion of the particulate drug by the cells. Ingestion by the cells of the dispersion of the pharmaceutical composition as particles may include phagocytosis or adsorption of the particle on the surface of the cells. Furthermore, in a preferred form of the invention, the particles during contact with the cells have a higher concentration than the thermodynamic or apparent solubility allowing the particles to remain in the form of particles during ingestion and delivery to the brain by means of the cells. For marginally soluble drugs, for example indinavir, the ex vivo procedure can be used provided that the isolated cells are able to phagocytose the particles of the pharmaceutical composition at a faster rate than the competent dissolution process. The particles must be large enough to allow the cells to phagocytose the particles and supply them to the brain before the complete dissolution of the particle. In addition, the concentration of the pharmaceutical composition must be greater than the thermodynamic or apparent solubility of the composition such that the particle is capable of remain in the crystalline state during phagocytosis. The loaded cells can be administered intrathecally, epidurally or by means of any procedure that can be used to deliver medicine in the central nervous system. The loaded cells can also be administered in the vascular system of the mammal, including administration in the venous system through the carotid artery. The administration step can be by means of bolus injection or by means of continuous administration. In another preferred embodiment, the pharmaceutical composition in the form of particles is administered directly into the central nervous system of the mammal, particularly the cerebrospinal fluid (CSF). The particles that are of sufficient size are ingested by the phagocytic cells resident in the CSF and are transported by passing through the cerebrospinal fluid-brain barrier (CFBB) to the brain. The particles can also be adsorbed on the surface of those cells. Generally, CFBB acts to prevent the entry of drugs into the brain. This invention exploits the use of those phagocytic cells as drug delivery containers, particularly when the brain has an increase in the rate of macrophages passing through the CFBB. In a preferred form of the invention, the pharmaceutical agent will be supplied when the percentage of macrophages that cross CFBB. In a preferred form of the invention the pharmaceutical agent will be delivered when the percentage of macrophages crossing the CFBB is in excess of 2%, more preferably in excess of 3%, more preferably in excess of 4% and more preferably in excess of %. Certain viruses and bacteria can be ingested by phagocytic cells and continue to remain inside those cells. However, the cells loaded with the drug particles are effective in treating these infections because the drug is concentrated in the phagocytic cells and the infectious organism is exposed to much larger amounts of the drug thus killing the organism. In addition, after passing to the brain, the solubilizable particles with acid dissolve due to the lower pH levels within the phagocytic cells releasing drug concentrations. A concentration gradient is formed with higher concentrations of the pharmaceutical composition within an endosomal body of the phagocytic cells and lower concentrations outside the endosome. Thus the content of the particles within the macrophage are released into the brain for curative purposes. Over time, viral and bacterial organisms resident in the brain are exposed to the drug at concentrations greater than what is typically capable of being delivered by oral administration. In another preferred modality, the pharmaceutical composition in the form of particles is administered directly into the vascular system of a mammal. The particles can be ingested by phagocytic cells residing in the vascular system or absorbed in the cell wall. Once the particle is ingested by the loaded cell, a certain percentage of the charged cells will be transported through the blood-brain barrier to the brain in a manner similar to transport through the cerebrospinal-brain fluid barrier.

In another preferred embodiment, the method includes treating a patient having the central nervous system infected with HIV by delivering an anti-HIV composition to the brain using one of the processes described above. Suitable anti-H IV compositions include protease inhibitors. Examples of protease inhibitors include indinavir, ritonavir, saquinavir, and nelfinavir. The anti-HIV composition can also be a reverse transcriptase inhibitor of nucellose. Examples of the nucleoside reverse transcriptase inhibitor include zidovudine, didanosine, stavudine, zalcitabine and lamivudine. The anti-VI H composition can also be a non-nucleoside reverse transcriptase inhibitor. Examples of non-nucleoside reverse transcriptase inhibitors include nevirapine and delaviradine. Treatment of VI H infection by means of nanosuspensions of anti-retroviral agents for the high supply to the central nervous system (CNS) Dementia associated with HIV-1 remains a continuous medical problem, despite the advent of anti-retroviral therapy highly active (HAART). The poor penetration in the CNS of many anti-retroviral drugs only gives sub-therapeutic levels of the drug, resulting in the development of resistant viral strains. These continue to infect the brain and also escape from their sanctuaries to infect the systemic circulation. Clearly, superior drug delivery systems are required for a better supply to the brain (see reference 1, Limoges et al.). Monocyte-derived macrophages (MDM) are preferred as a vector for the delivery of the anti-retroviral drug because they are the natural target cell of the viral infection of the brain (see reference 2, Nottet et al), and because they are phagocytic rents to suspensions of particulate drugs (see reference 3, Moghimi et al). Therefore the ingestion of the drug and the subsequent supply to the brain is to be expected. The protease inhibitor, indinavir, is preferred as a drug that will remain in the form of particles at a neutral pH for ingestion by the macrophages, but which would dissolve under the acid conditions of the phagolisozoma, providing the desired therapeutic efficacy. Example 1: Nanosuspensions of indinavir for a greater supply to the CNS by targeting the macrophages A nano-suspension formulation of I ndinavir (IND) (composition 1) suitable for the targeting of the macrophages was prepared and its good physical stability was demonstrated after of storage. Since the dose burden of the 1ND nanosuspension effectively suppressed replication t eliminated the cytopathogenicity associated with viruses without affecting cell viability measurements. The IND nanosuspension was prepared by high pressure homogenization of an aqueous suspension at an alkaline pH in the presence of the appropriate stabilizing surfactants (see composition 1). The lipoid E80 is a mixture of phospholipids manufactured by Lipoid GmbH. The process was optimized for several parameters including temperature and homogenization cycles. The particle size was measured using light scattering and the stability of the suspension was determined using stress tests specifically designed and short-term stability studies. Composition 1 To determine the activity of the IND nansouspension, MDM were infected with HIV-1 and the virus was removed 12 hours after exposure. The infected cells were treated overnight with 500 uM of drug nanosuspension. The replicated DM M were left untreated as controls (CON). The culture creams were collected and their reverse transcriptase (RT) activity was determined every two days. The viability of MDM was determined 9 days after infection by means of the thiazolyl blue (MTT) conversion assay. The weighted average volume size of the particles was about 1.6 microns, having 99% of the particles (in volume) a size smaller than 8.4 microns. Process optimization studies indicated that longer homogenization times and lower temperatures produced smaller particles. The suspension was exposed to multiple stress tests to estimate its long-term stability. As can be seen in figure 1, the suspension passed all the stress tests. In addition, as shown in Figure 2, the suspension was stable for at least 6 months at 5o C determined by means of particle size analysis. The MDM of CON infected with HlV-1 showed a promptive cutopathogenicity (swelling, multinuclear giant cells and cell death, with high sustained levels of RT activity during the 9 days of the observation period.) The MDM I ND nanosuspension showed a reduction of 99% in the RT activity compared to the controls without cytopathogenicity The suspension of the drug did not have statistically significant effects on the viability of the MDM Although specific modalities have been illustrated and described, numerous modifications come to mind without departing from the spirit of the present invention and the scope of protection is limited only by the scope of the appended claims References: (1) J. Limoges, I. Kadiu, D. Morin, M. Chaubal, A. Weling, B. Rabinow, and H: E Gendelman , "Sustained Antiretroviral Activity of Indinavir Nanosuspensions in primary Monocute-Derived Macrophages, poster presentation, 1 1nd Conference on Return and Opportunistic Infections, February 8-1 1, 2004, San Francisco. (2) HSLM Nottet S. Dhawan, "HIV-1 entry into Brain : Mechanisms for the infiltration of HIV-1 infected macrophages across the blood-brain barrier "in The Neurology of AIDS, eds, HE Gendelman, S. Lipton, L. Epstein, S. Svindells, 1998, Chapan & Hall, p. 55. (3) S. Moein Moghimi, A. Christy Hunter and J. Clifford Murray "Long-circulating and target-Specific Nanoparticles: Theory to Practice", Pharmacological Reviews, 53: 283-318, 2001.

Claims (46)

1. CLAIMS 1. A pharmaceutical composition of an anti-retroviral agent for delivery to the brain of a mammal consisting of a dispersion of a pharmaceutical composition provided as particles having an average particle size of about 1 00 nm to 100 microns and serving to administer to the mammal for supplying to the brain an effective amount of the pharmaceutical composition by means of cells capable of reaching the brain.
2. 2. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is administered to the central nervous system of the mammal. 3. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is administered to the central vascular system of the mammal. 4. The pharmaceutical composition of claim 3, wherein the pharmaceutical composition is administered to the venous system of the mammal. 5. The pharmaceutical composition of claim 3, wherein the pharmaceutical composition is administered to the carotid artery of the mammal. 6. The pharmaceutical composition of claim 1, wherein the cells are capable of phagocytosis. The pharmaceutical composition of claim 1, wherein the cells are selected from the group consisting of T lymphocytes, monocytes, granulocytes, neutrophils, basophils, eosinophils and their mixtures. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is ingested in the form of particles by the cells. 9. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is adsorbed in the form of particles on the surface of the cells. 10. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is contacted with the cells in the form of particles. eleven . The pharmaceutical composition of claim 10, wherein the pharmaceutical composition is contacted with isolated cells. 12. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition is contacted with isolated cells by means of a cell separator.
3. 3. The pharmaceutical composition of claim 1, wherein a portion of the particles is not dissolved prior to delivery to the brain. The pharmaceutical composition of claim 1, wherein the dispersion has a particle concentration above a thermodynamic or apparent particle solubility. 15. The pharmaceutical composition of claim 1, wherein the pharmaceutical composition further contains a surfactant. 16. The pharmaceutical composition of claim 15, wherein which surfactant is selected from the group consisting of anionic surfactants, cationic surfactants, non-ionic surfactants and surface active biological modifiers. The pharmaceutical composition of claim 16, wherein the anionic surfactant is selected from the group consisting of: alkyl sulfonates, alkyl phosphates, alkyl phosphonates, potassium laurate, ethanolamine stearate, sodium lauryl sulfate, sodium dodecylsulphonate, sodium, alkyl polyoxyethylene sulphates, sodium alginate, dioctyl sodium sulfosuccinate, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl onisine, phosphididylserine, phosphatidic acid and their salts, glyceryl esters, sodium carboxymethylcellulose, cholic acid and acids bilears and their salts, cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid, glycodeoxycholic acid. 18. The pharmaceutical composition of claim 15, wherein the cationic surfacer is selected from the group consisting of: quaternary ammonium compounds, benzalkonium chloride, cetylimethylammonium bromide, quifosans, lauryldimethylbenzylammonium chloride, acyl carnitine hydrochlorides, and alkyl pyridinium halides. 19. The pharmaceutical composition of claim 15, wherein the nonionic surfactant is selected from the group consisting of: esters of polyoxyethylene fatty alcohols, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, sorbitan esters , glycerol monostearate, polyethylene glycols, polypropylene glycols, cetyl alcohol, cesto-phearyl alcohol, sphearyl alcohol, aryl alkyl polyether alcohols, polyoxyethylene-copolymers polyoxypropylene, poloxamines, meyylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, non-chrysaline cellulose, polysaccharides, starch, starch derivatives, hydroxiefyl starch, polyvinyl alcohol, glyceryl esters and polyvinylpyrrolidone. The pharmaceutical composition of claim 19, wherein the polyoxyethylene fatty acid ester is polyethylene 660. 21 hydroxystearate. The pharmaceutical composition of claim 15, wherein the surface-active biological modifiers are selected from the group consisting of: albumin, casein, hirudin or pro-active hosts. 22. The pharmaceutical composition of claim 15, wherein the biological modifiers active on the surface are polysaccharides. 23. The pharmaceutical composition of claim 22, wherein the polysaccharide is selected from the group consisting of starch, heparin, chitosan and mixtures thereof. 24. The pharmaceutical composition of claim 15, wherein the surfacer consists of a phospholipid. 25. The pharmaceutical composition of claim 24, wherein the phospholipid is selected from naïve and syni- ne phospholipids. 26. The pharmaceutical composition of claim 24, wherein the phospho lipid is selected from the group consisting of phosphatidylcholine, phosphatidylenealamin, diacylglycero-phosphoencylamine, dimyristoyl-glycero-phosphoencylamine (DMPE), dipalmiioyl-glycero-phospho-phenolamine (DPPE), distearoyl -glycero-phosphoethanolamine (DSPE), dioleoyl-glycero- phosphoethanolamine (DOPE)), dosphatidylserine, phosphatidylinosiol, phosphaidylglycerol, phosphatidic acid, lysophophospholipids, polyethylene glycol-phospholipid conjugates, egg or soy phospholipids 27. The pharmaceutical composition of claim 24, wherein the phospholipid additionally had a functional group for link in a covalent way to a ligand. 28. The pharmaceutical composition of claim 24, wherein the ligand is selected from the group consisting of PEG, proteins, peptides, carbohydrates, glycopro- teins, antibodies and pharmaceutically active agents. 29. The pharmaceutical composition of claim 15, wherein the surfactant consists of bile acid or a salt thereof. 30. The pharmaceutical composition of claim 29, wherein the surfactant is selected from deoxycholic acid, glycolic acid, glycodeoxycholic acid, iaurocolic acid and salts of those acids. 31 The pharmaceutical composition of claim 15, wherein the surfactant consists of an oxyethylene-oxypropylene copolymer. 32. The pharmaceutical composition of claim 31, wherein the copolymer of oxyethylene and oxypropylene is a block copolymer. 33. The pharmaceutical composition of claim 1, wherein the particles of the dispersion can be amorphous, semi-crystalline, crystalline or a combination thereof determined by means of XRD. 34. The pharmaceutical composition of claim 1, in which the anti-retroviral agent is a protease inhibitor. 35. The pharmaceutical composition of claim 34, wherein the protease inhibitor is selected from the group consisting of: indinavir, rifonavir, saquinavir, and nelfinavir. 36. The pharmaceutical composition of claim 1, wherein the antiretroviral agent is indinavir. 37. The pharmaceutical composition of claim 1, wherein the dialysis agent is a nucleoside reverse transcriptase inhibitor. 38. The pharmaceutical composition of claim 37, wherein the nucleoside reverse transcriptase inhibitor is selected from the group consisting of: zidovudine, didanosine, stavudine, zalcitabine and lamivudine. 39. The pharmaceutical composition of claim 1, wherein the therapeutic agent is a non-nucleoside reverse transcriptase inhibitor. 40. The pharmaceutical composition of claim 30, wherein the non-nucleoside reverse transcriptase inhibitor is selected from the group consisting of nevirapine and delaviradine. 41 The pharmaceutical composition of claim 1, wherein the diabetic agent is used to eradicate an HIV infection in the central nervous system. 42. The pharmaceutical composition of claim 1, wherein the step of providing a dispersion consists of the step of homogenizing the pharmaceutical composition through a process of homogenization. 43. The pharmaceutical composition of claim 1, wherein the step of providing a dispersion consists of the step of homogenizing the pharmaceutical composition through a microprecipitation / homogenization process. 44. The pharmaceutical composition of claim 1, wherein the dispersion of the pharmaceutical composition is administered intra-fecally or epidurally. 45. The pharmaceutical composition of claim 1, wherein the dispersion of the pharmaceutical composition is sterilized prior to administration. 46. The pharmaceutical composition of claim 45, wherein the sterilization is performed by means of thermal sterilization or gamma radiation.