Patent Publication Number: US-2012035142-A1

Title: Polymorphs of darunavir

Description:
FIELD OF THE INVENTION 
     The present invention relates to new forms of darunavir, pharmaceutical compositions comprising same, and use thereof in treating retroviral infections. 
     BACKGROUND OF THE INVENTION 
     Darunavir is a second-generation protease inhibitor used for treating human immunodeficiency virus (HIV) infection. Co-administration of darunavir with the antiretroviral drug ritonavir was approved by the FDA in 2006 for the treatment of HIV patients who have already been administered with other antiretroviral drugs. 
     Darunavir is chemically named [(1S,2R)-3-[[(4-aminophenyl)sulfonyl](2-methylpropyl)amino]-2-hydroxy-1-(phenylmethyppropyl]-carbamic acid (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl ester, and is represented by the following chemical structure: 
     
       
         
         
             
             
         
       
     
     Darunavir and processes for its preparation are disclosed in EP 715618, WO 99/67417, U.S. Pat. No. 5,968,942, U.S. Pat. No. 6,248,775 and in Bioorganic and Chemistry Letters, 8, 687-690, 1998. 
     Several pseudopolymorphic forms of darunavir are described in US 2005/0250845 including the ethanolate, hydrate, methanolate, acetonate, dichloromethanate, ethylacetate solvate, 1-methoxy-2-propanolate, anisolate, tetrahydrofuranate, isopropanolate and mesylate solvates of darunavir. 
     Darunavir ethanolate is marketed in the United States under the trade name PREZISTA® by Tibotec. PREZISTA® is available as an orange, oval-shaped, film coated tablet for oral administration. Darunavir monoethanolate solvate is a white to off-white powder with solubility of approximately 0.15 mg/mL in water at 20° C. 
     A new form of a compound may possess physical properties that differ from, and are advantageous over, those of other crystalline or amorphous forms. These include, packing properties such as molar volume, density and hygroscopicity; thermodynamic properties such as melting temperature, vapor pressure and solubility; kinetic properties such as dissolution rate and stability under various storage conditions; surface properties such as surface area, wettability, interfacial tension and shape; mechanical properties such as hardness, tensile strength, compactibility, handling, flow and blend; and filtration properties. Variations in any one of these properties affect the chemical and pharmaceutical processing of a compound as well as its bioavailability and may often render the new form advantageous for medical use. 
     There still remains an unmet need for additional solid state forms of darunavir having good physiochemical properties, desirable bioavailability, and advantageous pharmaceutical parameters. 
     SUMMARY OF THE INVENTION 
     The present invention provides new polymorphic forms of darunavir, as well as a novel amorphous form of darunavir, pharmaceutical compositions comprising said compounds, methods for their preparation and use thereof in treating retroviral infections and, in particular, HIV infection. 
     The present invention is based in part on the unexpected finding that the new forms disclosed herein possess advantageous physicochemical properties which render their processing as medicaments beneficial. The forms of the present invention have good bioavailability as well as desirable stability characteristics enabling their incorporation into a variety of different formulations particularly suitable for pharmaceutical utility. 
     According to one aspect, the present invention provides a crystalline tetrahydrofuran solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 22.8±0.1 and 16.4±0.1. 
     In one embodiment, the present invention provides a crystalline tetrahydrofuran solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 22.8±0.1, 16.4±0.1, 22.4±0.1 and 20.9±0.1. 
     In another embodiment, the present invention provides a crystalline tetrahydrofuran solvate of darunavir having at least 3 X-ray diffraction peaks selected from about 6.9±0.1, 11.0±0.1, 13.6±0.1, 16.1±0.1, 16.4±0.1, 17.1±0.1, 18.4±0.1, 20.2±0.1, 20.9±0.1, 22.4±0.1, 22.8±0.1 and 23.2±0.1 degrees 2-theta. 
     In particular embodiments, the present invention provides a crystalline tetrahydrofuran solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 6.9±0.1, 11.0±0.1, 13.6±0.1, 16.1±0.1, 16.4±0.1, 17.1±0.1, 18.4±0.1, 20.2±0.1, 20.9±0.1, 22.4±0.1, 22.8±0.1 and 23.2±0.1. 
     According to another aspect, the present invention provides a crystalline dimethylsulfoxide solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 20.6±0.1 and 21.2±0.1. 
     In some embodiments, the present invention provides a crystalline dimethylsulfoxide solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 20.6±0.1, 21.2±0.1, 16.6±0.1 and 23.0±0.1. 
     In other embodiments, the present invention provides a crystalline dimethylsulfoxide solvate of darunavir having at least 3 X-ray diffraction peaks selected from about 7.1±0.1, 9.3±0.1, 10.6±0.1, 11.4±0.1, 13.9±0.1, 16.6±0.1, 17.3±0.1, 18.5±0.1, 20.1±0.1, 20.6±0.1, 21.2±0.1, 23.0±0.1, 27.1±0.1 and 28.1±0.1 degrees 2-theta. 
     In particular embodiments, the present invention provides a crystalline dimethylsulfoxide solvate of darunavir having an X-ray powder diffraction pattern with diffraction peaks at 2-theta values of about 7.1±0.1, 9.3±0.1, 10.6±0.1, 11.4±0.1, 13.9±0.1, 16.6±0.1, 17.3±0.1, 18.5±0.1, 20.1±0.1, 20.6±0.1, 21.2±0.1, 23.0±0.1, 27.1±0.1 and 28.1±0.1. 
     In yet another aspect, the present invention provides an amorphous form of darunavir having an IR spectrum with characteristic peaks at about 1454 and 1369 cm −1 . In certain embodiments, the amorphous form of darunavir has an IR spectrum with characteristic peaks at about 1454, 1369, 771 and 553 cm −1 . 
     In specific embodiments, the present invention provides a pharmaceutical composition comprising as an active ingredient any one of the darunavir forms of the present invention, and a pharmaceutically acceptable carrier. 
     In a particular embodiment, the pharmaceutical composition is in the form of a tablet. 
     In various embodiments, the present invention provides a pharmaceutical composition comprising as an active ingredient any one of the darunavir forms of the present invention, and a pharmaceutically acceptable carrier for use in treating retroviral infections. 
     In particular embodiments, the retroviral infection is a human immunodeficiency virus (HIV) infection. 
     In other embodiments, the pharmaceutical composition of the present invention is co-administered in combination with another antiretroviral drug. An exemplary and non-limiting embodiment is the co-administration with ritonavir. 
     In some embodiments, the present invention provides a method of inhibiting retrovirus protease activity comprising administering to a subject in need thereof an effective amount of a composition comprising any one of the darunavir forms of the present invention. 
     In additional embodiments, the present invention provides use of any one of the darunavir forms of the present invention for the preparation of a medicament for inhibiting retrovirus protease activity. 
     In particular embodiments, the method and use disclosed herein are designated for inhibiting HIV protease activity. 
     In specific embodiments, the subject is a mammal, preferably a human. 
     Further embodiments and the full scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a characteristic X-ray diffraction pattern of the crystalline tetrahydrofuran solvate of darunavir. 
         FIG. 2  is a characteristic X-ray diffraction pattern of the crystalline tetrahydrofuran solvate of darunavir in comparison to darunavir ethanolate API. 
         FIG. 3  is a characteristic Thermogravimetric analysis (TGA) of the crystalline tetrahydrofuran solvate of darunavir. 
         FIG. 4  is a characteristic IR spectrum of the crystalline tetrahydrofuran solvate of darunavir (4A) in comparison to darunavir ethanolate API (4B). 
         FIG. 5  is a characteristic Raman spectrum of the crystalline tetrahydrofuran solvate of darunavir. 
         FIG. 6  is a polarized light micrograph of the crystalline tetrahydrofuran solvate of darunavir. 
         FIG. 7  is a dynamic vapor sorption (DVS) isotherm plot of the crystalline tetrahydrofuran solvate of darunavir. Sorption is represented by diamonds and desorption is represented by squares. 
         FIG. 8  are HPLC chromatograms of the crystalline dimethylsulfoxide solvate of darunavir (panel A), the crystalline tetrahydrofuran solvate of darunavir (panel B), the amorphous darunavir of the present invention (panel C), and darunavir ethanolate API (panel D) slurry in pH 1.2 buffer. Panel E is a chromatogram of darunavir ethanolate API standard solution (STD). 
         FIG. 9  is a characteristic X-ray diffraction pattern of the crystalline dimethylsulfoxide solvate of darunavir. 
         FIG. 10  are characteristic X-ray diffraction patterns of the crystalline dimethylsulfoxide solvate of darunavir (panels B-D) in comparison to darunavir ethanolate API (panel F) and the amorphous darunavir form (panels A and E). 
         FIG. 11  is a characteristic Thermogravimetric analysis (TGA) of the crystalline dimethylsulfoxide solvate of darunavir. 
         FIG. 12  is a characteristic IR spectrum of the crystalline dimethylsulfoxide solvate of darunavir. 
         FIG. 13  is a characteristic Raman spectrum of the crystalline dimethylsulfoxide solvate of darunavir. 
         FIG. 14  is a dynamic vapor sorption (DVS) isotherm plot of the crystalline dimethylsulfoxide solvate of darunavir. Sorption is represented by diamonds and desorption is represented by squares. 
         FIG. 15  is a characteristic IR spectrum of the amorphous darunavir of the present invention. 
         FIG. 16  is a characteristic Raman spectrum of the amorphous darunavir of the present invention. 
         FIG. 17  is a dynamic vapor sorption (DVS) isotherm plot of the amorphous darunavir of the present invention. Sorption is represented by diamonds and desorption is represented by squares. 
         FIG. 18  is a dynamic vapor sorption (DVS) isotherm plot of darunavir ethanolate API. Sorption is represented by diamonds and desorption is represented by squares. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to novel pseudopolymorphic and amorphous forms of [(1S,2R)-3-[[(4-aminophenyl)sulfonyl](2-methylpropyl)amino]-2-hydroxy-1-(phenylmethyl)propyl]carbamic acid (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl ester having structural formula: 
     
       
         
         
             
             
         
       
     
     The present invention is further directed to pharmaceutical compositions comprising the pseudopolymorphic forms, as well as the novel amorphous form of the compound of the present invention and a pharmaceutically acceptable carrier and their use in treating retroviral infections. 
     Polymorphs are two or more solid state phases of the same chemical compound that possess different arrangement and/or conformation of the molecules. Pseudopolymorphs are polymorphs which incorporate one or more solvents into the structure. Different polymorphs and pseudopolymorphs of an active pharmaceutical compound can exhibit different physical and chemical properties such as color, stability, processability, dissolution and even bioavailability. 
     An important physical property of a compound used as an active ingredient of a medicament is the stability at ambient conditions, especially to moisture, and under storage conditions. The identification and characterization of various polymorphs and pseudopolymorphs of a pharmaceutically active compound is therefore of great significance in obtaining medicaments with desired properties including a specific dissolution rate, milling property, bulk density, thermal stability or shelf-life. The darunavir forms of the present invention possess improved characteristics of hygroscopicity, bulk density and solubility in aqueous media. Furthermore, the darunavir forms of the present invention have improved chemical and solid state stability. Hence, these forms may be more stable when stored over prolonged periods of time. 
     In one embodiment, the present invention relates to crystalline tetrahydrofuran solvates of darunavir having any stoichiometry from 0.5 tetrahydrofuran to 5.0 molecules of tetrahydrofuran per molecule of darunavir. Exemplary stoichiometries are hemisolvates, monosolvates, disolvates or trisolvates. 
     Provided herein is a crystalline tetrahydrofuran solvate of darunavir which is characterized by a unique X-ray diffraction pattern having characteristic peaks expressed in degrees 2-theta at about 22.8±0.1 and 16.4±0.1. Preferably, the X-ray diffraction pattern has additional characteristic peaks expressed in degrees 2-theta at about 22.4±0.1 and 20.9±0.1. More preferably, the X-ray diffraction pattern has additional characteristic peaks expressed in degrees 2-theta at about 11.0±0.1, 17.1±0.1 and 20.2±0.1. Most preferably, the X-ray diffraction pattern has characteristic peaks expressed in degrees 2-theta at about 6.9±0.1, 11.0±0.1, 13.6±0.1, 16.1±0.1, 16.4±0.1, 17.1±0.1, 18.4±0.1, 20.2±0.1, 20.9±0.1, 22.4±0.1, 22.8±0.1 and 23.2±0.1. 
     The crystalline form of darunavir tetrahydrofuran solvate of the present invention can be further characterized by its melting point and by using various techniques including infrared absorption, Raman spectrometry, solid state NMR, and thermal analysis (e.g. thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC)). 
     Specifically, the crystalline tetrahydrofuran solvate of darunavir of the present invention is characterized by TGA as having an approximately 9-11% weight loss at a temperature range of room temperature (RT) to 200° C. substantially attributed to solvate release. The form is further characterized by Infrared spectroscopy to have characteristic peaks and their relative intensities 1  at the following wavenumbers: 3437m, 3348s, 3253m, 3062vw, 3030vw, 2961m, 2901w, 2872w, 1704vs, 1646w, 1596vs, 1548m, 1503m, 1455w, 1368w, 1342m, 1317s, 1263s, 1244m, 1227w, 1185w, 1153vs, 1090m, 1044m, 1021m, 988m, 944m, 910w, 885vw, 862vw, 839w, 767m, 741m, 698w, 673m, 632w, 581m, 554s, and 502vw cm −1 .  1 vs=very strong, s=strong, m=medium, w=weak, vw=very weak, br=broad. 
     The present invention further relates to crystalline dimethylsulfoxide solvates of darunavir having any stoichiometry from 0.5 dimethylsulfoxide to 5.0 molecules of dimethylsulfoxide per molecule of darunavir. Particular stoichiometries are hemisolvates, monosolvates, disolvates or trisolvates. 
     Provided herein is a crystalline dimethylsulfoxide solvate of darunavir which is characterized by a unique X-ray diffraction pattern having characteristic peaks expressed in degrees 2-theta at about 20.6±0.1 and 21.2±0.1. Preferably, the X-ray diffraction pattern has additional characteristic peaks expressed in degrees 2-theta at about 16.6±0.1 and 23.0±0.1. More preferably, the X-ray diffraction pattern has additional characteristic peaks expressed in degrees 2-theta at about 18.5±0.1 and 17.3±0.1. Most preferably, the X-ray diffraction pattern has characteristic peaks expressed in degrees 2-theta at about 7.1±0.1, 9.3±0.1, 10.6±0.1, 11.4±0.1, 13.9±0.1, 16.6±0.1, 17.3±0.1, 18.5±0.1, 20.1±0.1, 20.6±0.1, 21.2±0.1, 23.0±0.1, 27.1±0.1 and 28.1±0.1. 
     Additionally, the crystalline form of darunavir dimethylsulfoxide solvate is characterized by an about 10-12% weight loss at a temperature range of RT to 230° C. substantially attributed to solvate release. The form is further characterized by Infrared spectroscopy with characteristic peaks and their relative intensities 2  at 3407br, 3342s, 3250m, 3062vw, 3026vw, 2962m, 2901w, 2872w, 1704vs, 1646w, 1596vs, 1546m, 1500m, 1467w, 1454w, 1372w, 1340m, 1311s, 1263s, 1244m, 1227w, 1183w, 1155vs, 1091m, 1043m, 1023m, 988m, 947m, 891w, 862vw, 842w, 769m, 744m, 700w, 671m, 554s, and 502vw cm −1 .  2 vs=very strong, s=strong, m=medium, w=weak, vw=very weak, br=broad. 
     The present invention further relates to amorphous darunavir characterized by an X-ray diffraction pattern having a single broad peak expressed between 10 and 25 [2θ°]. The amorphous darunavir of the present invention is further characterized by IR peaks and their relative intensities 2  at the following wavenumbers: 3466br, 3386s, 3250m, 3066vw, 3026vw, 2960m, 2901w, 2872w, 1706vs, 1633m, 1597vs, 1537m, 1503m, 1454w, 1369w, 1315s, 1260m, 1149vs, 1091s, 1041m, 1017m, 937w, 885vw, 833w, 771m, 702m, 673m, 632w, and 553s cm −1 .  2 vs=very strong, s=strong, m=medium, w=weak, vw=very weak, br=broad. 
     The crystalline pseudopolymorphic forms of the present invention as well as the novel amorphous form can be prepared by a variety of methods, including for example, crystallization/precipitation or recrystallization from a suitable solvent, sublimation, growth from a melt, solid state transformation from another phase, crystallization/precipitation from a supercritical fluid, and jet spraying. Techniques for crystallization or recrystallization of crystalline forms from a solvent mixture include, for example, evaporation of the solvent, decreasing the temperature of the solvent mixture, crystal seeding a supersaturated solvent mixture of the molecule and/or salt, freeze drying the solvent mixture, and addition of antisolvents (countersolvents) to the solvent mixture. The term “antisolvent” as used herein refers to a solvent in which the compound has low solubility. 
     Suitable solvents and anti-solvents for preparing crystals include polar and nonpolar solvents. The choice of solvent or solvents is typically dependent upon one or more factors, including solubility of the compound in such solvent, crystallization technique, and vapor pressure of the solvent. Combinations of solvents may be employed; for example, the compound may be solubilized into a first solvent followed by the addition of an antisolvent to decrease the solubility of the compound in the solution and to induce crystallization. Suitable solvents include, but are not limited to, polar aprotic solvents and polar protic solvents, and mixtures thereof. Particular examples of suitable polar aprotic solvents include, but are not limited to, acetonitrile, tetrahydrofuran (THF), dichloromethane, acetone, dimethylformamide, and dimethylsulfoxide. 
     Seed crystals may be added to any crystallization mixture to promote crystallization as is known in the art. Alternatively, crystalline forms may be obtained by distillation or solvent addition techniques such as those known to those skilled in the art. Suitable solvents for this purpose include any of those solvents described herein, including protic polar solvents, such as alcohols (for example, methanol, ethanol, and isopropanol), aprotic polar solvents (including those listed above), and also ketones (for example, acetone, methyl ethyl ketone, and methyl isobutyl ketone). 
     Exemplary processes used to prepare each of the pseudopolymorphic darunavir forms of the present invention are provided herein. 
     Methods for “crystallization from solution” include, but are not limited to, a concentration method, a slow cooling method, a reaction method (diffusion method, electrolysis method), a hydrothermal growth method, a fusing agent method, and so forth. The solution can be a supersaturated solution, optionally heated to temperatures bellow the solvent boiling point. The recovery of the solid state forms can be done for example, by filtering the suspension and drying. 
     In particular, the darunavir forms of the present invention can be prepared by the slurry method as is well known in the art. Suspensions of the active ingredient in different solvents or mixture of solvents are prepared and shaken for long intervals (typically 24 hours). 
     The darunavir forms of the present invention can be prepared using slow precipitation from saturated solutions in different solvents or mixture of solvents which are allowed to evaporate at room temperatures. Alternatively the saturated solutions can be heated followed by their cooling to induce precipitation as is known in the art. 
     Encompassed by the present invention are methods of antisolvent precipitation where an antisolvent is added to the saturated solution of the active ingredient in different solvents or mixture of solvents to induce precipitation. 
     Within the scope of the present invention are high pressure techniques where the active ingredient is compressed using various forces as is known in the art. 
     The novel forms of darunavir are useful as pharmaceuticals for inhibiting retroviral infections. The present invention thus provides pharmaceutical compositions comprising the pseudopolymorphs and amorphous form disclosed herein and a pharmaceutically acceptable carrier. The solid state polymorphs of the present invention can be safely administered orally or non-orally (e.g., topical, rectal). The pharmaceutical compositions can be formulated as tablets (including sugar-coated tablets and film-coated tablets), powders, granules, capsules (including soft capsules), orally disintegrating tablets, and sustained-release preparations as is well known in the art. 
     Pharmacologically acceptable carriers that may be used in the context of the present invention include various organic or inorganic carriers including, but not limited to, excipients, lubricants, binders, disintegrants, water-soluble polymers and basic inorganic salts. The pharmaceutical compositions of the present invention may further include additives such as, but not limited to, preservatives, antioxidants, coloring agents, sweetening agents, souring agents, bubbling agents and flavorings. 
     Suitable excipients include e.g. lactose, sucrose, D-mannitol, starch, cornstarch, crystalline cellulose, light silicic anhydride and titanium oxide. Suitable lubricants include e.g. magnesium stearate, sucrose fatty acid esters, polyethylene glycol, talc and stearic acid. Suitable binders include e.g. hydroxypropyl cellulose, hydroxypropylmethyl cellulose, crystalline cellulose, a-starch, polyvinylpyrrolidone, gum arabic powder, gelatin, pullulan and low-substitutional hydroxypropyl cellulose. Suitable disintegrants include e.g. crosslinked povidone (any crosslinked 1-ethenyl-2-pyrrolidinone homopolymer including polyvinylpyrrolidone (PVPP) and 1-vinyl-2-pyrrolidinone homopolymer), crosslinked carmellose sodium, carmellose calcium, carboxymethyl starch sodium, low-substituted hydroxypropyl cellulose, cornstarch and the like. Suitable water-soluble polymers include e.g. cellulose derivatives such as hydroxypropyl cellulose, polyvinylpyrrolidone, hydroxypropylmethyl cellulose, methyl cellulose and carboxymethyl cellulose sodium, sodium polyacrylate, polyvinyl alcohol, sodium alginate, guar gum and the like. Suitable basic inorganic salts include e.g. basic inorganic salts of sodium, potassium, magnesium and/or calcium. Particular embodiments include the basic inorganic salts of magnesium and/or calcium. Basic inorganic salts of sodium include, for example, sodium carbonate, sodium hydrogen carbonate, disodiumhydrogenphosphate, etc. Basic inorganic salts of potassium include, for example, potassium carbonate, potassium hydrogen carbonate, etc. Basic inorganic salts of magnesium include, for example, heavy magnesium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, magnesium metasilicate aluminate, magnesium silicate, magnesium aluminate, synthetic hydrotalcite, aluminahydroxidemagnesium and the like. Basic inorganic salts of calcium include, for example, precipitated calcium carbonate, calcium hydroxide, etc. 
     Suitable preservatives include e.g. sodium benzoate, benzoic acid, and sorbic acid. Suitable antioxidants include e.g. sulfites, ascorbic acid and a-tocopherol. Suitable coloring agents include e.g. food colors such as Food Color Yellow No. 5, Food Color Red No. 2 and Food Color Blue No. 2 and the like. Suitable sweetening agents include e.g. saccharin sodium, dipotassium glycyrrhetinate, aspartame, stevia and thaumatin. Suitable souring agents include e.g. citric acid (citric anhydride), tartaric acid and malic acid. Suitable bubbling agents include e.g. sodium bicarbonate. Suitable flavorings include synthetic substances or naturally occurring substances, including e.g. lemon, lime, orange, menthol and strawberry. 
     The solid forms of the present invention are particularly suitable for oral administration in the form of tablets, capsules, pills, dragées, powders, granules and the like. A tablet may be made by compression or molding, optionally with one or more excipients as is known in the art. Specifically, molded tablets may be made by molding in a suitable machine a mixture of the powdered active ingredient moistened with an inert liquid diluent. 
     The tablets and other solid dosage forms of the pharmaceutical compositions described herein may optionally be scored or prepared with coatings and shells, such as enteric coatings and other coatings well known in the art. They may also be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile, other polymer matrices and the like. The active ingredient can also be in micro-encapsulated form, if appropriate, with one or more of the above-described excipients. 
     The present invention provides a method of inhibiting retrovirus protease activity comprising administering to a subject in need thereof an effective amount of a composition comprising any one of the darunavir forms of the present invention. 
     “A therapeutically effective amount” as used herein refers to an amount of an agent which is effective, upon single or multiple dose administration to the subject in providing a therapeutic benefit to the subject. In one embodiment, the therapeutic benefit is inhibiting retrovirus protease activity, or in prolonging the survivability of a subject with such a viral infection beyond that expected in the absence of such treatment. In additional embodiments, the darunavir forms of the present invention are used for the preparation of a medicament for treating diseases caused by retroviruses such as HIV infections, e.g. Acquired Immune Deficiency Syndrome (AIDS) and AIDS-Related Complex (ARC). 
     The present invention further provides the administration of the darunavir forms in combination therapy with 1 to 3 other active ingredients. Such “other active ingredients”, according to the principles of the present invention include, but are not limited to, other antiretroviral drugs (e.g. Etravirine, Raltegravir, Rifabutin). In specific embodiments, the present invention provides the co-administration of darunavir with ritonavir. 
     It is further contemplated that the combination therapy will include the two or more active ingredients within a single pharmaceutical composition as well as the two or more active ingredients in two separate pharmaceutical compositions administered to the same subject simultaneously or at a time interval determined by a skilled artisan. 
     The principles of the present invention are demonstrated by means of the following non-limitative examples. 
     EXAMPLES 
     Example 1 
     Preparation of the Crystalline Tetrahydrofuran Solvate of Darunavir 
     Darunavir tetrahydrofuran solvate of the present invention was prepared by dissolving about 1 g of Darunavir ethanolate in 5 ml of a tetrahydrofuran solvent. The solvent was then allowed to evaporate at room temperature (approximately 25° C.) until crystals were formed. 
     Alternatively, the darunavir tetrahydrofuran solvate of the present invention was prepared by dissolving Darunavir ethanolate in a tetrahydrofuran solvent, followed by the addition of the antisolvent isopropanol (IPA) to induce precipitation of the crystals. 
     Alternatively, the darunavir tetrahydrofuran solvate of the present invention was prepared by dissolving Darunavir ethanolate in tetrahydrofuran (THF): isopropyl acetate (iPrOAc) at a ratio of 1:2 or tetrahydrofuran (THF): methyl tert-butyl ether (MTBE) at a ratio of 1:2, heating the mixture to 60° C., followed by cooling using an ice-bath to induce crystallization. 
     Example 2 
     Characterization of the Crystalline Tetrahydrofuran Solvate of Darunavir 
     This new polymorphic form showed an endothermic peak in Differential Scanning calorimetry (DSC; Mettler Toledo DSC 1; 10° C./min) at ˜95° C. X-ray powder diffraction (XRPD; Rigaku D/MAX 2200, CuKα, 40 kV, 40 mA, DivSlit 1 deg, DivH.L.Slit 10 mm, SctSlit 1 deg, RecSlit 0.3 mm, 10 deg/min) shows unique characteristic peaks ( FIG. 1 ; Table 1). The X-ray diffraction pattern of the tetrahydrofuran solvate of darunavir of the present invention has a unique fingerprint which differs from the X-ray diffraction pattern of darunavir ethanolate API ( FIG. 2 ). The XRPD and DSC spectra remained unchanged even after storage at 25° C. for 2 weeks, thus indicating crystal stability. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 X-ray diffraction peaks of darunavir tetrahydrofuran solvate 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 d-spacing 
                 Width at 
                 Relative 
               
               
                   
                 2-theta 
                 [Å] 
                 half height 
                 intensity* (%) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 6.898 
                 12.8032 
                 0.213 
                 39.7 
               
               
                   
                 9.142 
                 9.6656 
                 0.153 
                 26.8 
               
               
                   
                 10.340 
                 8.5484 
                 0.338 
                 19.9 
               
               
                   
                 10.980 
                 8.0518 
                 0.253 
                 51.8 
               
               
                   
                 13.579 
                 6.5155 
                 0.223 
                 38.2 
               
               
                   
                 16.060 
                 5.5143 
                 0.377 
                 32.3 
               
               
                   
                 16.398 
                 5.4013 
                 0.232 
                 98.9 
               
               
                   
                 17.123 
                 5.1744 
                 0.174 
                 54.1 
               
               
                   
                 18.380 
                 4.8231 
                 0.440 
                 35.8 
               
               
                   
                 19.824 
                 4.4749 
                 0.512 
                 26.8 
               
               
                   
                 20.221 
                 4.3879 
                 0.337 
                 52.8 
               
               
                   
                 20.920 
                 4.2428 
                 0.411 
                 54.2 
               
               
                   
                 22.381 
                 3.9691 
                 0.563 
                 86.4 
               
               
                   
                 22.801 
                 3.8970 
                 0.325 
                 100.0 
               
               
                   
                 23.160 
                 3.8374 
                 0.427 
                 33.0 
               
               
                   
                 27.740 
                 3.2133 
                 0.528 
                 19.2 
               
               
                   
                 28.041 
                 3.1795 
                 0.528 
                 18.9 
               
               
                   
                   
               
               
                   
                 *Relative intensities may vary among samples. 
               
            
           
         
       
     
     Thermogravimetric analysis (TGA; Mettler Toledo TGA/DSC 1100, 10° C./min) showed a weight loss of approximately 1.3% at temperatures of 60-100° C. and another weight loss of approximately 8.5% at temperatures of 100-190° C. ( FIG. 3 ). Infrared (IR) spectroscopy revealed significant differences between the tetrahydrofuran solvate form of the present invention and the known ethanolate form, particularly at the alcohol region (3100-3400 cm −1;    FIGS. 4A and 4B , respectively). The Raman spectrum is shown in  FIG. 5 . The characteristic Raman peaks of the darunavir tetrahydrofuran solvate of the present invention appear at about 62, 171, 283, 555, 636, 672, 760, 824, 1004, 1091, 1155, 1376, 1448, 1596, 1647, 2871, 2937, 2974, and 3064 cm −1 . Differences in the Raman spectra between the tetrahydrofuran solvate form of the present invention and the known ethanolate form of darunavir appear at least at the following wavenumbers (cm −1 ): 2871, 1647, 1376 and 1155. Polarized light microscopy of the crystals revealed small birefringent plates (Nikon LV100POL equipped with 5 megapixel CCD, Physical lens 50×;  FIG. 6 ). The bulk density of the darunavir tetrahydrofuran solvate of the present invention is 0.431±0.007 g/ml. 
     About 10 mg of the tetrahydrofuran solvate form of the present invention were used to test the hygroscopicity (DVS) from 0% to 90% according to the details on Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Parameters for hygroscopicity measurements 
               
               
                 (dynamic vapor sorption; DVS) 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 dm/dt 
                 Start 
                 Stop 
                 Temp 
               
               
                 Stage number 
                 Stage type 
                 (%/min) 
                 PP (%) 
                 PP (%) 
                 (° C.) 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 1 
                 dm/dt 
                 0.002 
                 0.0 
                 0.0 
                 25.0 
               
               
                 2 
                 dm/dt 
                 0.002 
                 10.0 
                 10.0 
                 25.0 
               
               
                 3 
                 dm/dt 
                 0.002 
                 20.0 
                 20.0 
                 25.0 
               
               
                 4 
                 dm/dt 
                 0.002 
                 30.0 
                 30.0 
                 25.0 
               
               
                 5 
                 dm/dt 
                 0.002 
                 40.0 
                 40.0 
                 25.0 
               
               
                 6 
                 dm/dt 
                 0.002 
                 50.0 
                 50.0 
                 25.0 
               
               
                 7 
                 dm/dt 
                 0.002 
                 60.0 
                 60.0 
                 25.0 
               
               
                 8 
                 dm/dt 
                 0.002 
                 70.0 
                 70.0 
                 25.0 
               
               
                 9 
                 dm/dt 
                 0.002 
                 80.0 
                 80.0 
                 25.0 
               
               
                 10 
                 dm/dt 
                 0.002 
                 90.0 
                 90.0 
                 25.0 
               
               
                 11 
                 dm/dt 
                 0.002 
                 80.0 
                 80.0 
                 25.0 
               
               
                 12 
                 dm/dt 
                 0.002 
                 70.0 
                 70.0 
                 25.0 
               
               
                 13 
                 dm/dt 
                 0.002 
                 60.0 
                 60.0 
                 25.0 
               
               
                 14 
                 dm/dt 
                 0.002 
                 50.0 
                 50.0 
                 25.0 
               
               
                 15 
                 dm/dt 
                 0.002 
                 40.0 
                 40.0 
                 25.0 
               
               
                 16 
                 dm/dt 
                 0.002 
                 30.0 
                 30.0 
                 25.0 
               
               
                 17 
                 dm/dt 
                 0.002 
                 20.0 
                 20.0 
                 25.0 
               
               
                 18 
                 dm/dt 
                 0.002 
                 10.0 
                 10.0 
                 25.0 
               
               
                 19 
                 dm/dt 
                 0.002 
                 0.0 
                 0.0 
                 25.0 
               
               
                   
               
            
           
         
       
     
     The tetrahydrofuran solvate form of the present invention was found to be slightly hygroscopic (1.366% weight gain from 0% to 90%;  FIG. 7 ). 
     The tetrahydrofuran solvate of darunavir of the present invention was further evaluated for its chemical stability. The results are summarized in Table 3. Specifically, about 3 mg of the compound were weighed accurately into a 20 ml clear glass vial and stored under the following conditions: 40° C., 60° C., 40° C./RH 75%, 60° C./RH 75%, and light (25° C.), for 2 weeks. A sample stored at −20° C. was used as control. A slight increase in Total Related Substances (TRS) was found at 40° C. which was more significant at 60° C. and 60° C./75% RH. In contrast, no increase was observed when the tetrahydrofuran solvate was stored under exposure to light at 25° C., both at the end of 1 st  and 2 nd  week. Additionally, no change was observed in the physical appearance at the end of the 1 st  and 2 nd  week for samples stored at 40° C., 40° C./RH 75% and 25° C. under light. Samples that were stored at 60° C. and 60° C./75% RH were found stuck to the glass vial. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Solid stability of darunavir tetrahydrofuran solvate at 40° C., 60° C., 
               
               
                 40° C./75% RH, 60° C./75% RH and under exposure to light for 7 days 
               
               
                 and 14 days 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Sample 
                 Weight 
                   
                   
                 Remaining 
               
               
                 Condition 
                 Time 
                 number 
                 (mg) 
                 Appearance 
                 TRS % 
                 % 
               
               
                   
               
               
                 −20° C. 
                 7 d 
                 1 
                 2.446 
                 No change 
                 3.54 
                 — 
               
               
                   
                   
                 2 
                 2.547 
                 No change 
                 3.52 
               
               
                   
                 14 d  
                 1 
                 1.935 
                 No change 
                 3.44 
                 — 
               
               
                   
                   
                 2 
                 3.040 
                 No change 
                 3.53 
               
               
                 40° C. 
                 7 d 
                 1 
                 2.469 
                 No change 
                 4.11 
                 99.83 
               
               
                   
                   
                 2 
                 2.775 
                 No change 
                 4.02 
               
               
                   
                 14 d  
                 1 
                 2.628 
                 No change 
                 4.08 
                 99.64 
               
               
                   
                   
                 2 
                 3.422 
                 No change 
                 4.15 
               
               
                 60° C. 
                 7 d 
                 1 
                 2.903 
                 Stuck 
                 6.25 
                 97.24 
               
               
                   
                   
                 2 
                 2.222 
                 Stuck 
                 5.70 
               
               
                   
                 14 d  
                 1 
                 3.166 
                 Stuck 
                 8.88 
                 94.12 
               
               
                   
                   
                 2 
                 2.512 
                 Stuck 
                 9.37 
               
               
                 40° C./ 
                 7 d 
                 1 
                 2.532 
                 No change 
                 2.84 
                 100.77 
               
               
                 75% RH 
                   
                 2 
                 2.824 
                 No change 
                 3.17 
               
               
                   
                 14 d  
                 1 
                 2.227 
                 No change 
                 2.82 
                 101.52 
               
               
                   
                   
                 2 
                 2.681 
                 No change 
                 2.65 
               
               
                 60° C./ 
                 7 d 
                 1 
                 2.479 
                 Stuck 
                 5.05 
                 97.84 
               
               
                 75% RH 
                   
                 2 
                 2.650 
                 Stuck 
                 4.17 
               
               
                   
                 14 d  
                 1 
                 2.869 
                 Stuck 
                 4.34 
                 98.59 
               
               
                   
                   
                 2 
                 2.856 
                 Stuck 
                 5.19 
               
               
                 light 
                 7 d 
                 1 
                 3.002 
                 No change 
                 3.56 
                 100.02 
               
               
                   
                   
                 2 
                 2.859 
                 No change 
                 3.64 
               
               
                   
                 14 d  
                 1 
                 2.345 
                 No change 
                 3.63 
                 100.78 
               
               
                   
                   
                 2 
                 3.012 
                 No change 
                 3.57 
               
               
                   
               
            
           
         
       
     
     The aqueous solubility of the tetrahydrofuran solvate of darunavir of the present invention was measured. Specifically, about 10 mg of the compound was accurately weighed into a 4 ml clear glass vial followed by the addition of 2.5 ml buffer (at different pH) to the vial. The vial was then mounted on a Thermomixer and was kept shaking for 24 hours at 25° C. The solution was filtered through 0.45 μm PTFE filter. The pH value and concentration of the filtrate were checked by pH meter and HPLC (Agilent 1200; Column: Zorbax SB C18, 4.6 mm×150 mm ID×5 μm; Profile of mobile phase: t=0 water 70, ACN 30; t=15,20 water 0, ACN 100; Column temperature 30° C.; Mobile rate 1.0 mL/min; Detector wavelength 265 nm; The typical retention time of Darunavir is 7.7 min), respectively. The results are summarized in Table 4 and  FIG. 8  panel B. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Solubility results of darunavir tetrahydrofuran 
               
               
                 solvate in aqueous buffers 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Solubility 
                   
                   
               
               
                   
                 Testing media 
                 (mg/ml) 
                 Appearance 
                 Final pH 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 water 
                 0.27 
                 Many particles 
                 5.664 
               
               
                   
                 pH 1.2 
                 1.47* 
                 Many particles 
                 1.197 
               
               
                   
                 pH 4.5 
                 0.27 
                 Many particles 
                 4.508 
               
               
                   
                 pH 6.8 
                 0.24 
                 Many particles 
                 6.789 
               
               
                   
                 pH 7.4 
                 0.23 
                 Many particles 
                 7.431 
               
               
                   
                   
               
               
                   
                 *degraded 
               
            
           
         
       
     
     Example 3 
     Preparation of the Crystalline Dimethylsulfoxide Solvate of Darunavir 
     Darunavir dimethylsulfoxide solvate of the present invention was prepared by dissolving Darunavir ethanolate in dimethylsulfoxide at 60° C. followed by cooling using an ice-bath to induce crystallization. 
     Alternatively, the darunavir dimethylsulfoxide solvate of the present invention was prepared by dissolving about 1 g of Darunavir ethanolate in 2.5 ml dimethylsulfoxide at 80° C. Water (10 ml) was then added to induce crystallization. 
     Alternatively, the darunavir dimethylsulfoxide solvate of the present invention was prepared by dissolving Darunavir ethanolate in dimethylsulfoxide followed by the addition of the antisolvent isopropanol (IPA) to induce precipitation of the crystals. 
     Alternatively, the darunavir dimethylsulfoxide solvate of the present invention was prepared by dissolving Darunavir ethanolate in either one of the following solvent mixtures: dimethylsulfoxide (DMSO):methanol (MeOH) at a ratio of 1:10, dimethylsulfoxide (DMSO):toluene at a ratio of 1:10 or dimethylsulfoxide (DMSO): ethanol (EtOH) at a ratio of 1:10 at 60° C. The mixtures were then allowed to evaporate until crystals were formed. 
     Example 4 
     Characterization of the Crystalline Dimethylsulfoxide Solvate of Darunavir 
     The crystalline dimethylsulfoxide solvate of darunavir showed an endothermic peak at ˜115° C. using Differential Scanning calorimetry. The X-ray powder diffraction of the darunavir dimethylsulfoxide solvate of the present invention is presented in  FIG. 9  and Table 5. The X-ray diffraction pattern shows a unique fingerprint ( FIG. 10 , panels B, C, and D) which differs from the diffraction pattern of the known ethanolate crystalline form ( FIG. 10 , panel F). The XRPD and DSC spectra remained unchanged even after storage at 25° C. for 2 weeks indicating crystal stability. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 X-ray diffraction peaks of darunavir dimethylsulfoxide solvate 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 d-spacing 
                 Width at 
                 Relative 
               
               
                   
                 2-theta 
                 [Å] 
                 half height 
                 intensity* (%) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 7.080 
                 12.4755 
                 0.277 
                 29.5 
               
               
                   
                 9.318 
                 9.4832 
                 0.247 
                 16.2 
               
               
                   
                 10.640 
                 8.3078 
                 0.461 
                 26.3 
               
               
                   
                 11.361 
                 7.7826 
                 0.277 
                 22.5 
               
               
                   
                 13.878 
                 6.3759 
                 0.332 
                 34.9 
               
               
                   
                 16.640 
                 5.3232 
                 0.281 
                 63.7 
               
               
                   
                 17.340 
                 5.1101 
                 0.214 
                 37.6 
               
               
                   
                 18.500 
                 4.7922 
                 0.543 
                 39.2 
               
               
                   
                 20.060 
                 4.4228 
                 0.535 
                 27.2 
               
               
                   
                 20.580 
                 4.3123 
                 0.326 
                 100.0 
               
               
                   
                 21.200 
                 4.1874 
                 0.310 
                 68.7 
               
               
                   
                 22.999 
                 3.8638 
                 0.594 
                 60.7 
               
               
                   
                 27.060 
                 3.2925 
                 0.254 
                 25.7 
               
               
                   
                 28.140 
                 3.1685 
                 0.456 
                 24.1 
               
               
                   
                   
               
               
                   
                 *Relative intensities may vary among samples. 
               
            
           
         
       
     
     Thermogravimetric analysis of darunavir dimethylsulfoxide solvate showed a weight loss of approximately 11% at a temperature range of RT-230° C. substantially attributed to the release of solvate molecules ( FIG. 11 ).  FIG. 12  shows the Infrared (IR) spectrum of the darunavir dimethylsulfoxide solvate of the present invention which has significant differences from other known forms of darunavir, particularly at the alcohol region (3100-3400 cm −1 ). The Raman spectrum is shown in  FIG. 13 . The characteristic Raman peaks of the darunavir dimethylsulfoxide solvate of the present invention appear at about 108, 172, 284, 333, 391, 555, 673, 707, 768, 824, 954, 1004, 1031, 1081, 1155, 1184, 1208, 1291, 1341, 1375, 1414, 1459, 1595, 1649, 1700, 2871, 2915, 2937, 2962, 2989, 3064, and 3340 cm −1 . Differences in the Raman intensity between the dimethylsulfoxide solvate form of the present invention and the known ethanolate form of darunavir appear at least at the following wavenumbers (cm −1 ): 3340, 2915, 2871, 1700, 1649, 1414, 1375, 1341, 1291, 1208, 1184, 1031, 954, 707, 391, 333, and 108. The bulk density of the darunavir dimethylsulfoxide solvate of the present invention is 0.472±0.008 g/ml, approximately 26% denser when compared to the bulk density (0.374±0.009 g/mL) of the known ethanolate form. 
     About 10 mg of the dimethylsulfoxide solvate form of the present invention were used to test the hygroscopicity (DVS) from 0% to 90% according to the details on Table 2 hereinabove. The dimethylsulfoxide solvate form of the present invention was found to be only slightly hygroscopic (0.9431% weight gain from 0% to 90%;  FIG. 14 ). 
     The dimethylsulfoxide solvate of darunavir of the present invention was further evaluated for its chemical stability. The results are summarized in Table 6. Specifically, about 3 mg of the compound was accurately weighed into a 20 ml clear glass vial and stored under the following conditions: 40° C., 60° C., 40° C./RH 75%, 60° C./RH 75%, and light (25° C.), for 2 weeks. A sample stored at −20° C. was used as control. No significant drop in recovery values or increase in TRS was observed at 40° C., 40° C./75% RH and under exposure to light at 25° C., while a slight increase was found at 60° C. and 60° C./75% RH. The extent of degradation of the dimethylsulfoxide solvate of darunavir was less than 50% in comparison to the known ethanolate form, under the accelerated test conditions (60° C. and 60° C./75% RH). Additionally, no change was observed in the physical appearance at the end of the 1 st  and 2 nd  week for samples stored at 40° C., 40° C./RH 75% and 25° C. under light. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Solid stability of darunavir dimethylsulfoxide solvate at 40° C., 60° C., 
               
               
                 40° C./75% RH, 60° C./75% RH and under light exposure for 7 days 
               
               
                 and 14 days 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Sample 
                 Weight 
                   
                   
                 Remaining 
               
               
                 Condition 
                 Time 
                 number 
                 (mg) 
                 Appearance 
                 TRS % 
                 % 
               
               
                   
               
               
                 −20° C. 
                 7 d 
                 1 
                 2.881 
                 No change 
                 1.22 
                 — 
               
               
                   
                   
                 2 
                 2.684 
                 No change 
                 1.22 
               
               
                   
                 14 d  
                 1 
                 1.932 
                 No change 
                 1.22 
                 — 
               
               
                   
                   
                 2 
                 3.244 
                 No change 
                 1.27 
               
               
                 40° C. 
                 7 d 
                 1 
                 2.226 
                 No change 
                 1.21 
                 99.21 
               
               
                   
                   
                 2 
                 2.853 
                 No change 
                 1.21 
               
               
                   
                 14 d  
                 1 
                 3.557 
                 No change 
                 1.27 
                 100.19 
               
               
                   
                   
                 2 
                 2.825 
                 No change 
                 1.27 
               
               
                 60° C. 
                 7 d 
                 1 
                 2.957 
                 Stuck 
                 1.43 
                 99.95 
               
               
                   
                   
                 2 
                 2.767 
                 Stuck 
                 1.29 
               
               
                   
                 14 d  
                 1 
                 2.755 
                 Stuck 
                 2.07 
                 99.91 
               
               
                   
                   
                 2 
                 3.175 
                 Stuck 
                 2.12 
               
               
                 40° C./ 
                 7 d 
                 1 
                 2.534 
                 No change 
                 1.22 
                 99.54 
               
               
                 75% RH 
                   
                 2 
                 2.786 
                 No change 
                 1.24 
               
               
                   
                 14 d  
                 1 
                 2.639 
                 No change 
                 1.23 
                 100.31 
               
               
                   
                   
                 2 
                 2.640 
                 No change 
                 1.27 
               
               
                 60° C./ 
                 7 d 
                 1 
                 2.129 
                 Stuck 
                 2.09 
                 99.01 
               
               
                 75% RH 
                   
                 2 
                 2.791 
                 Stuck 
                 2.08 
               
               
                   
                 14 d  
                 1 
                 3.352 
                 Stuck 
                 2.04 
                 99.85 
               
               
                   
                   
                 2 
                 2.341 
                 Stuck 
                 1.91 
               
               
                 light 
                 7 d 
                 1 
                 2.228 
                 No change 
                 1.29 
                 99.59 
               
               
                   
                   
                 2 
                 2.615 
                 No change 
                 1.19 
               
               
                   
                 14 d  
                 1 
                 3.633 
                 No change 
                 1.22 
                 100.12 
               
               
                   
                   
                 2 
                 2.724 
                 No change 
                 1.21 
               
               
                   
               
            
           
         
       
     
     The aqueous solubility of the dimethylsulfoxide solvate of darunavir of the present invention was measured. Specifically, about 10 mg of the compound was accurately weighed into a 4 ml clear glass vial followed by the addition of 2.5 ml buffer (at different pH) to the vial. The vial was then mounted on a Thermomixer and kept shaking for 24 hours at 25° C. The solution was filtered through 0.45 μm PTFE filter. The pH value and concentration of the filtrate were checked by pH meter and HPLC, respectively. The results are summarized in Table 7 and  FIG. 8  panel A. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Solubility results of darunavir dimethylsulfoxide 
               
               
                 solvate in aqueous buffers 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Solubility 
                   
                   
               
               
                   
                 Testing media 
                 (mg/ml) 
                 Appearance 
                 Final pH 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 water 
                 0.23 
                 Many particles 
                 6.001 
               
               
                   
                 pH 1.2 
                 1.36* 
                 Many particles 
                 1.236 
               
               
                   
                 pH 4.5 
                 0.22 
                 Many particles 
                 4.486 
               
               
                   
                 pH 6.8 
                 0.21 
                 Many particles 
                 6.785 
               
               
                   
                 pH 7.4 
                 0.20 
                 Many particles 
                 7.437 
               
               
                   
                   
               
               
                   
                 *degraded 
               
            
           
         
       
     
     Example 5 
     Preparation of Amorphous Darunavir 
     The amorphous darunavir form of the present invention was prepared by slow precipitation from a saturated solution using the following solvent systems: methyl isobutyl ketone (MIBK), isopropyl acetate (iPrOAc), acetonitrile (ACN), dichloromethane (DCM), ethyl acetate (EtOAc) wet and anhydrous, and in the following mixtures of solvents: ACN:Acetone (1:1), at 60° C. with ACN: Toluene (1:6), DCM: MeOH (1:6), Acetone:MeOH (1:6), ACN:MTBE (1:9), Acetone:MTBE (1:9), 2-MeTHF:MeOH (1:8), THF:MeOH (1:9). 
     Alternatively, the amorphous form was prepared in the following solvent/antisolvent systems: methyl ethyl ketone (MEK)/Methyl tert-butyl ether (MTBE), CH 2 Cl 2 /Toluene, acetonitrile (ACN)/H 2 O, 2-MeTHF/IPA and MIBK/Toluene. 
     Alternatively, the amorphous form of the present invention was prepared by dissolving about 1 g of Darunavir ethanolate in 1.5 ml CH 2 Cl 2 . CH 2 Cl 2  was then evaporated under ambient conditions until a precipitate formed. 
     Example 6 
     Characterization of Amorphous Darunavir 
     The amorphous darunavir of the present invention showed a broad X-ray diffraction peak between 10 and 25 [2θ°] characteristic of an amorphous powder ( FIG. 10 , panels A and E). The XRPD remained unchanged even after storage at 25° C. for 2 weeks indicating stability of the amorphous form. The IR spectrum of the amorphous form is shown in  FIG. 15 . Unique and specific spectral differences between the amorphous form of US 2005/0250845 and the amorphous form of the present invention appear in 2 spectral regions: 1500-1320 cm −1  (hereinafter region 1) and 800-500 cm −1  (hereinafter region 2). 
     Specifically, whereas the amorphous form of US 2005/0250845 shows no peaks in region 1, the amorphous form of the present invention is characterized by two single absorption bands at 1454 and 1369 cm −1 . Additionally, the amorphous form of US 2005/0250845 shows 3 absorption bands at 750, 702 and 672 cm −1  in region 2. The amorphous form of the present invention shows 2 additional peaks in this region, at 771 and 553 cm −1 . The Raman spectrum is shown in  FIG. 16 . The characteristic Raman peaks of the amorphous darunavir of the present invention appear at about 61, 285, 553, 622, 673, 767, 841, 1004, 1091, 1145, 1459, 1597, 2931, 2966, and 3063 cm −1 . Differences in the Raman intensity between the amorphous form of the present invention and the known ethanolate form of darunavir appear at least at the following wavenumbers (cm −1 ): 841, 622 and 61. The bulk density of the amorphous darunavir of the present invention is 0.445±0.012 g/ml. 
     About 10 mg of amorphous darunavir of the present invention were used to test the hygroscopicity (DVS) from 0% to 90% according to the details on Table 2 hereinabove. The amorphous form of the present invention was found to be hygroscopic (2.617% weight gain from 0% to 90%);  FIG. 17 ). 
     The amorphous darunavir form of the present invention was further evaluated for its chemical stability. The results are summarized in Table 8. Specifically, about 3 mg of the compound was accurately weighed into a 20 ml clear glass vial and stored under the following conditions: 40° C., 60° C., 40° C./RH 75%, 60° C./RH 75%, and light (25° C.), for 2 weeks. A sample stored at −20° C. was used as control. A slight increase in TRS was found at 40° C., 40° C./75% RH, 60° C. and 60° C./75% RH, while no increase was observed for the amorphous form that was stored under exposure to light at 25° C., both at the end of 1 st  and 2 nd  weeks. Additionally, no change was observed in the physical appearance at the end of the 1 st  and 2 nd  week for samples stored at 40° C., 40° C./RH 75% and 25° C. under light. 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Solid stability of amorphous darunavir at 40° C., 60° C., 40° C./75% RH, 
               
               
                 60° C./75% RH and under light exposure for 7 days and 14 days 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Sample 
                 Weight 
                   
                   
                 Remaining 
               
               
                 Condition 
                 Time 
                 number 
                 (mg) 
                 Appearance 
                 TRS % 
                 % 
               
               
                   
               
               
                 −20° C. 
                 7 d 
                 1 
                 2.496 
                 No change 
                 2.05 
                 — 
               
               
                   
                   
                 2 
                 2.210 
                 No change 
                 2.05 
               
               
                   
                 14 d  
                 1 
                 2.812 
                 No change 
                 2.07 
                 — 
               
               
                   
                   
                 2 
                 3.434 
                 No change 
                 2.08 
               
               
                 40° C. 
                 7 d 
                 1 
                 3.025 
                 No change 
                 3.03 
                 97.22 
               
               
                   
                   
                 2 
                 2.861 
                 No change 
                 3.07 
               
               
                   
                 14 d  
                 1 
                 2.780 
                 No change 
                 3.35 
                 97.40 
               
               
                   
                   
                 2 
                 2.991 
                 No change 
                 3.36 
               
               
                 60° C. 
                 7 d 
                 1 
                 2.775 
                 Stuck 
                 3.97 
                 96.60 
               
               
                   
                   
                 2 
                 2.780 
                 Stuck 
                 3.95 
               
               
                   
                 14 d  
                 1 
                 2.884 
                 Stuck 
                 4.04 
                 96.08 
               
               
                   
                   
                 2 
                 2.575 
                 Stuck 
                 4.00 
               
               
                 40° C./ 
                 7 d 
                 1 
                 2.726 
                 No change 
                 3.12 
                 96.36 
               
               
                 75% RH 
                   
                 2 
                 2.681 
                 No change 
                 3.29 
               
               
                   
                 14 d  
                 1 
                 2.385 
                 No change 
                 3.64 
                 97.10 
               
               
                   
                   
                 2 
                 2.887 
                 No change 
                 3.78 
               
               
                 60° C./ 
                 7 d 
                 1 
                 2.644 
                 Stuck 
                 4.17 
                 94.64 
               
               
                 75% RH 
                   
                 2 
                 2.660 
                 Stuck 
                 4.62 
               
               
                   
                 14 d  
                 1 
                 3.272 
                 Stuck 
                 3.97 
                 96.62 
               
               
                   
                   
                 2 
                 2.765 
                 Stuck 
                 4.01 
               
               
                 light 
                 7 d 
                 1 
                 2.575 
                 No change 
                 2.04 
                 99.11 
               
               
                   
                   
                 2 
                 2.797 
                 No change 
                 2.07 
               
               
                   
                 14 d  
                 1 
                 2.924 
                 No change 
                 2.06 
                 100.88 
               
               
                   
                   
                 2 
                 2.580 
                 No change 
                 2.06 
               
               
                   
               
            
           
         
       
     
     The aqueous solubility of amorphous darunavir of the present invention was measured. Specifically, about 10 mg of the compound was accurately weighed into a 4 ml clear glass vial followed by the addition of 2.5 ml buffer (at different pH) to the vial. The vial was then mounted on a Thermomixer and kept shaking for 24 hours at 25° C. The solution was filtered through 0.45 μm PTFE filter. The pH value and concentration of the filtrate were checked by pH meter and HPLC, respectively. The results are summarized in Table 9 and in  FIG. 8  panel C. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Solubility results of amorphous darunavir in aqueous buffers 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Solubility 
                   
                   
               
               
                   
                 Testing media 
                 (mg/ml) 
                 Appearance 
                 Final pH 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 water 
                 0.27 
                 Many particles 
                 5.765 
               
               
                   
                 pH 1.2 
                 1.73* 
                 Many particles 
                 1.226 
               
               
                   
                 pH 4.5 
                 0.27 
                 Many particles 
                 4.534 
               
               
                   
                 pH 6.8 
                 0.24 
                 Many particles 
                 6.790 
               
               
                   
                 pH 7.4 
                 0.23 
                 Many particles 
                 7.428 
               
               
                   
                   
               
               
                   
                 *degraded 
               
            
           
         
       
     
     Example 7 
     Hygroscopicity of Darunavir Ethanolate API 
     The hygroscopicities of the Darunavir forms of the present invention were compared to the hygroscopicity of Darunavir ethanolate API. Whereas the tetrahydrofuran and dimethylsulfoxide solvates of the present invention were only slightly hygroscopic (1.366% and 0.9431% weight gain from 0% to 90%, respectively), darunavir ethanolate (API) was hygroscopic with 2.180% weight gain from 0% to 90% ( FIG. 18 ). Additionally, darunavir ethanolate lost the solvate ethanol molecules during the desorption measurement. 
     Thus, the tetrahydrofuran and dimethylsulfoxide solvates of the present invention may possess longer term stability in humid environments and are thus more advantageous for use in the pharmaceutical industry in comparison to darunavir ethanolate. 
     While the present invention has been particularly described, persons skilled in the art will appreciate that many variations and modifications can be made. Therefore, the invention is not to be construed as restricted to the particularly described embodiments, and the scope and concept of the invention will be more readily understood by reference to the claims, which follow.