Amorphous tecovirimat preparation

Abstract

To provide an effective process of producing amorphous ST-246 from crystalline forms.SOLUTION: Disclosed are methods for preparation of amorphous N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide for the treatment or prophylaxis of viral infections and diseases associated therewith, particularly those viral infections and associated diseases caused by the orthopoxvirus. Also disclosed are methods for preparation of amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 61 / 856,240, filed July 19, 2013, the entirety of which is hereby incorporated by reference herein for all purposes.

[0002] Technical Field Described herein is a method for preparing amorphous tecovirimat for the treatment or prevention of viral infections and associated diseases, particularly those caused by orthopoxviruses. Tecovirimat has the trade name ST-246® and the chemical name N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide.

[0003] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with U.S. Government support under Contract No. HHSO100201100001C awarded by the Biomedical Advanced Research and Development Authority (BARDA). The U.S. Government has certain rights in this invention. [Background technology]

[0004] The genus Orthopox (family Orthopoxviridae) is a member of the Poxviridae family and the Choropoxivirinae subfamily. The genus consists of many viruses that cause significant disease in human and animal populations. Viruses in the Orthopox genus include cowpox, monkeypox, vaccinia, and variola (smallpox), all of which can infect humans.

[0005] The smallpox virus is of particular importance. Recent concerns about the use of variola as a biological weapon have highlighted the need for the development of small molecule therapeutics targeting orthopoxviruses. The variola virus is highly contagious, causing severe disease and high mortality in humans (Henderson et al. (1999) JAMA. 281:2127-2137). Furthermore, there is precedent for the use of variola as a biological weapon. During the French and Indian War (1754-1765), British soldiers distributed blankets used by smallpox patients to Native Americans in an attempt to spread the disease (Stern, EW and Stern, AE 1945. The effect of smallpox on the destiny of the Amerindian. Boston). The resulting epidemics caused 50% mortality among some Native American tribes (Stern, EW and Stern, AE). More recently, the Soviet government initiated a program to produce a highly virulent, weaponized form of smallpox in an aerosolized suspension (Henderson, supra). Even more worrying is the observation that recombinant forms of poxvirus have been developed that have the potential to cause disease in vaccinated animals (Jackson et al. (2001) J. Virol., 75:1205-1210).

[0006] The smallpox vaccination program ended in 1972; therefore, many individuals are no longer immune to smallpox infection. Even vaccinated individuals are no longer fully protected, especially against highly virulent or recombinant strains of the virus (Downie and McCarthy. (1958) J Hyg. 56:479-487; Jackson, supra). Therefore, if the smallpox virus were to be reintroduced into the human population, either deliberately or accidentally, mortality would be high.

[0007] Variola virus is naturally transmitted via aerosolized droplets to the respiratory mucosa, where replication in lymphoid tissues causes an asymptomatic infection that lasts 1-3 days. The virus spreads from the lymph to the skin, where replication in tiny cutaneous blood vessels, followed by infection and lysis of neighboring epithelial cells, causes skin lesions (Moss, B. (1990) Poxviridae and Their Replication, 2079-2111. In BN Fields and DM Knipe (eds.), Fields Virology. Raven Press, Ltd., New York). Two forms of disease are associated with variola virus infection: variola major (the most common form of disease, which results in a 30% mortality rate) and variola minor (which rarely epidemics and is rarely fatal (<1%)). Mortality is the result of disseminated intravascular coagulation, hypotension, and cardiovascular collapse, which may be exacerbated by coagulation defects in rare hemorrhagic forms of smallpox (Moss, supra).

[0008] Recent outbreaks of monkeypox virus highlight the need for the development of small molecule therapeutics that target viruses in the Orthopox genus. The emergence of monkeypox in the United States represents an emerging infection. Monkeypox and smallpox cause similar diseases in humans; however, monkeypox has a low mortality rate (1%).

[0009] Vaccination is the current means of preventing orthopoxvirus diseases, especially smallpox. Smallpox vaccines were developed using an attenuated strain of vaccinia virus, which replicates locally in more than 95% of vaccinated individuals and provides protective immunity against the variola virus (Modlin (2001) MMWR (Morb Mort Wkly Rep) 50:1-25). Adverse events associated with vaccination occur frequently (1:5000) and include systemic vaccinia and accidental transfer of vaccinia from the vaccination site. More serious complications, such as encephalitis, occur at a rate of 1:300,000 and are often fatal (Modlin, supra). The risk of adverse events is even more pronounced in immunocompromised individuals (Engler et al. (2002) J Allergy Clin Immunol. 110:357-365). Thus, vaccination is contraindicated for people with AIDS or allergic skin diseases (Engler et al.). Although protective immunity persists for many years, the antibody response to smallpox vaccination significantly declines 10 to 15 years after vaccination (Downie, supra). Additionally, vaccination may not protect against recombinant forms of orthopoxvirus. Recent studies have shown that a recombinant form of mousepox virus expressing IL-4 caused death in vaccinated mice (Jackson, supra). Given the side effects associated with vaccination, the contraindications for immunocompromised individuals, and the inability to protect against recombinant strains of the virus, better prophylactic and / or novel therapeutic agents for the treatment of smallpox virus infection are needed.

[0010] Vaccinia virus immune globulin (VIG) has been used to treat post-vaccination complications. VIG is an isotonic sterile solution of the immunoglobulin fraction of plasma from individuals who have received the vaccinia virus vaccine. It is used to treat eczema vaccinatum and some forms of progressive vaccinia. Because this product is available in limited quantities and difficult to obtain, it is not indicated for use in the event of a widespread smallpox outbreak (Modlin, supra).

[0011] Cidofovir ([(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine][HBMPC]) is a nucleoside analog approved for the treatment of CMV retinitis in AIDS patients. Cidofovir has been shown to have in vitro activity against many DNA-containing viruses, including adenoviruses, herpesviruses, hepadnaviruses, polyomaviruses, papillomaviruses, and orthopoxviruses. (Bronson et al. (1990) Adv. Exp. Med. Biol. 278:277-83; De Clercq et al. (1987) Antiviral Res. 8:261-272; de Oliveira et al. (1996) Antiviral Res. 31:165-172; Snoeck et al. (2001) Clin Infect. Dis. 33:597-602). Cidofovir has also been found to inhibit normal smallpox virus replication (Smee et al. (2002) Antimicrob. Agents Chemother. 46:1329-1335).

[0012] However, cidofovir administration presents many problems. Cidofovir has poor bioavailability and must be administered intravenously (Laezari et al. (1997) Ann. Intern. Med. 126:257-263). Furthermore, cidofovir causes dose-limiting nephrotoxicity when administered intravenously (Laezari et al.). In addition, cidofovir resistance has been demonstrated against multiple viruses. Cidofovir-resistant mutant strains of cowpox, monkeypox, vaccinia, and camelpox viruses have been isolated in the laboratory by passaging in the presence of the drug (Smee, supra). Cidofovir resistance represents a significant limitation to the use of this compound to treat orthopoxvirus replication. Thus, the low bioavailability, the need for intravenous administration, and the prevalence of resistant viruses highlight the need for the development of additional and alternative therapies to treat orthopoxvirus infections.

[0013] In addition to viral polymerase inhibitors such as cidofovir, many other compounds have been reported to inhibit orthopoxvirus replication (De Clercq. (2001) Clin Microbiol. Rev. 14:382-397). Historically, methisazone, the prototypic thiosemicarbazone, has been used for the prophylactic treatment of smallpox infection (Bauer et al. (1969) Am. J Epidemiol. 90:130-145). However, this compound class has not received significant attention since the eradication of smallpox due to generally unacceptable side effects, such as severe nausea and vomiting. Mechanism of action studies suggest that methisazone interferes with the translation of the L gene (De Clercq (2001) supra). Like cidofovir, methisazone is a fairly nonspecific antiviral compound and can inhibit many other viruses, including adenoviruses, picornaviruses, reoviruses, arboviruses, and myxoviruses. (Id.)

[0014] Another class of compounds potentially useful for the treatment of poxviruses is represented by inhibitors of adenosylhomocysteine ​​hydrolase (SAH). This enzyme is responsible for the conversion of S-adenosylhomocysteine ​​to adenosine and homocysteine, a step required for the methylation and maturation of viral mRNA. Inhibitors of this enzyme have shown efficacy in inhibiting vaccinia virus in vitro and in vivo (De Clercq et al. (1998) Nucleosides. 17:625-634). Structurally, all active inhibitors reported to date are analogs of the nucleoside adenosine. Many are carbocyclic derivatives, exemplified by neoplanacin A and 3-deazaneoplanacin A. These compounds have shown some efficacy in animal models; however, like many nucleoside analogs, they suffer from general toxicity and / or poor pharmacokinetic properties (Coulombe et al. (1995) Eur. J Drug Metab Pharmacokinet. 20:197-202; Obara et al. (1996) J Med. Chem. 39:3847-3852). It is highly unlikely that these compounds could be administered orally, and it is currently unclear whether they could act prophylactically against smallpox infection. Identification of non-nucleoside inhibitors of SAH hydrolase and other chemically tractable variola virus genomic targets that are orally bioavailable and possess favorable pharmacokinetic (PK) and absorption, distribution, metabolism, and excretion (ADME) properties would be a significant advance over reported nucleoside analogs. In summary, currently available compounds that inhibit smallpox virus replication are generally nonspecific and are limited in use by toxicity and / or questionable efficacy.

[0015] U.S. Pat. No. 6,433,016 (August 13, 2002) and U.S. Patent Application Publication No. 2002 / 0193443A1 (published December 19, 2002) describe a series of imidodisulfamide derivatives that are useful in treating orthopoxvirus infections.

[0016] New therapies and prophylactics are clearly needed for infections and diseases caused by orthopoxvirus infections.

[0017] Co-owned PCT Publication WO2004 / 112718 (published December 29, 2004) discloses the use of bi-, tri-, and tetracyclic acylhydrazide derivatives and analogs, and pharmaceutical compositions containing them, for the treatment or prevention of viral infections and associated diseases, particularly those caused by orthopoxviruses. Co-owned U.S. Patent Publication 2008 / 0004452 (published January 3, 2008) further discloses a process for producing ST-246. Finally, co-owned PCT Publication WO2011 / 119698 discloses a process for preparing various crystalline forms of ST-246.

[0018] Amorphous forms of ST-246 offer advantages over crystalline forms by having a faster dissolution rate, achieving supersaturation, and thus providing the potential for dose reduction, as well as avoiding the food effect and reducing pharmacokinetic variability. Thus, there is a need to develop an effective process for producing amorphous ST-246, especially from the crystalline form. [Prior art documents] [Non-patent literature]

[0019] [Non-Patent Document 1] Henderson et al. (1999) JAMA. 281:2127-2137 Summary of the Invention

[0020] The present invention provides a method for producing amorphous N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, said method comprising: (a) heating N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide in solid form at a temperature sufficient to cause it to melt; and (b) cooling the molten form of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, thereby producing amorphous N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide.

[0021] The present invention also provides a method for producing an amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, said method comprising: (a) preparing a liquid solution comprising N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, at least one polymer, and a solvent; and (b) spray drying said liquid solution, thereby forming said amorphous solid dispersion.

[0022] The present invention further provides a method for producing an amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, said method comprising: (a) preparing a liquid solution comprising N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, at least one polymer, and a solvent; and (b) spray drying said liquid solution, thereby forming said amorphous solid dispersion. [Brief explanation of the drawings]

[0023] [Figure 1] 1 shows the XRPD diffractogram of amorphous ST-246 and PEG-4000 solid dispersion described in Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0024] A process for producing ST-246 is described herein. The chemical name for ST-246 is N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, which has the formula: [ka]

[0025] definition In accordance with this detailed description, the following abbreviations and definitions apply: It must be noted that, as used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0026] The term "polymorphic form, polymorph, polymorphic form, crystalline form, physical form or crystalline polymorph" of ST-246 in the present invention refers to a crystalline modification of ST-246, which can be characterized by analytical methods such as X-ray powder diffraction pattern (XRPD), differential scanning calorimetry (DSC), by its melting point analysis or infrared spectroscopy (FTIR) or polarized light microscopy.

[0027] The term "hydrate," as used herein, refers to a compound or salt thereof that further contains a stoichiometric or non-stoichiometric amount of water bound by non-covalent intermolecular forces. Hydrates are formed by the combination of one or more molecules of water with one molecule of a substance, where the water retains its molecular state as HO, and such combinations can form one or more hydrates. The term "hemihydrate," as used herein, refers to a solid having 0.5 molecules of HO per molecule of substance.

[0028] The term "pharmaceutical composition" or "pharmaceutical formulation" is intended to encompass a pharmaceutical product comprising an active ingredient(s), a pharmaceutically acceptable excipient that constitutes a carrier, and any product resulting directly or indirectly from the combination, complexation, or aggregation of any two or more of the ingredients. Thus, pharmaceutical compositions of the present invention encompass any composition made by mixing an active ingredient, active ingredient dispersion or complex, additional active ingredient(s), and a pharmaceutically acceptable excipient.

[0029] PCT Publication WO2011 / 119698 discloses six polymorphs or crystalline structures of ST-246 with varying degrees of hydration. As mentioned above, the amorphous form of ST-246 is more desirable than the crystalline form because it has a faster dissolution rate and can achieve supersaturated concentrations. Therefore, it has recently been discovered that amorphous ST-246 can be prepared by heating solid or crystalline ST-246 to a temperature sufficient to cause melting, followed by rapid cooling. The melting temperature of ST-246 is approximately 196°C.

[0030] Preferably, heating of the solid or crystalline ST-246 is carried out at a temperature of at least about 196° C. and up to about 230° C. to minimize thermal decomposition of the ST-246.

[0031] Also preferably, the cooling step of the molten ST-246 is carried out at a temperature below about 0° C., more preferably below about −50° C., and most preferably in liquid nitrogen.

[0032] Again preferably, the starting material for ST-246 comprises a polymorph, e.g., a monohydrate polymorph. An example of such a polymorphic hydrate is polymorphic Form I of ST-246 (X-ray powder diffraction pattern having characteristic peaks at reflection angles 2θ of approximately 7.63, 10.04, 11.47, 14.73, 15.21, 15.47, 16.06, 16.67, 16.98, 18.93, 19.96, 20.52, 20.79, 22.80, 25.16, 26.53, 27.20, 27.60, 29.60, 30.23, 30.49, 30.68, 31.14, 33.65, 34.33, 35.29, 35.56, 36.30, 37.36, 38.42, and 38.66 degrees). and polymorphic Form III of ST-246, which exhibits an X-ray powder diffraction pattern with characteristic peaks at reflection angles 2θ of approximately 6.71, 9.05, 12.49, 13.03, 13.79, 14.87, 15.72, 16.26, 16.74, 18.10, 18.43, 19.94, 21.04, 21.51, 23.15, 23.51, 25.32, 26.24, 26.87, 27.32, 27.72, 28.55, 29.08, 29.50, 29.84, 31.27, 33.48, 35.36, and 39.56 degrees.

[0033] It has also been discovered that an amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide can be prepared by: (a) dissolving N-[(3aR,4R,4aR, (b) preparing a liquid solution comprising (5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, at least one polymer, and a solvent; and (b) spray-drying the liquid solution, thereby producing the amorphous solid dispersion. Typical equipment used for spray-drying is commercially available and includes, but is not limited to, a Buchi B290 manufactured by Buchi Corporation.

[0034] Preferably, the liquid solution comprises at least one solvent selected from the group consisting of tetrahydrofuran, ethyl alcohol, ethyl acetate, methyl ether ketone, dichloromethane, water, and mixtures thereof. More preferably, the solvent is tetrahydrofuran, methanol, or acetone.

[0035] Also preferably, the polymer is selected from the group consisting of methacrylic acid copolymer, hydroxypropyl methylcellulose (HPMC), HPMCP-H55, CAP, PVAP, HPMCAS-L, HPMCAS-M, HPMCAS-H, hypromellose, povidone, copovidone, HPC, poloxamer, PVP-VA, PVP (neutral), Klucel, Methocel, Ethocel, Plasdone, and mixtures thereof. More preferably, the polymer is (hydroxypropyl) methylcellulose and hydroxypropyl methylcellulose acetate succinate.

[0036] Again preferably, the liquid solution comprises a surfactant. More preferably, the surfactant is selected from the group consisting of: polysorbates, cremophor and corifol.

[0037] Preferably, the weight ratio of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide to polymer in the solution is about 1:50 to about 1:1, more preferably about 1:9 or about 1:2.

[0038] Furthermore, it has been discovered that an amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide can be prepared by: (a) dissolving N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide in solid form; ,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide in the presence of at least one polymer at a temperature sufficient to cause melting and form a liquid solution; and (b) cooling the solution of step (a), thereby forming the amorphous dispersion.

[0039] Preferably, the polymer is selected from the group consisting of polyethylene glycol, Gelucire, glycerol mono- and distearate, methacrylic acid copolymer, hydroxypropyl methylcellulose (HPMC), HPMCP-H55, CAP, PVAP, HPMCAS-L, HPMCAS-M, HPMCAS-H, hypromellose, povidone, copovidone, HPC, poloxamer, PVP-VA, PVP (neutral), Klucel, Methocel, Ethocel, Plasdone, and mixtures thereof. More preferably, the polymer is polyethylene glycol.

[0040] Again preferably, the liquid solution comprises a surfactant. More preferably, the surfactant is selected from the group consisting of: polysorbates, cremophor and corifol.

[0041] Preferably, the weight ratio of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide to polymer in the solution is about 1:50 to about 1:1, more preferably about 1:9 or about 1:2.

[0042] Also preferably, the cooling step of the molten ST-246 is carried out at a temperature below about 0° C., more preferably below about −50° C., and most preferably in liquid nitrogen.

[0043] The present invention also includes purified or isolated amorphous N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, further comprising a compound selected from the group consisting of a carrier, excipient, diluent, additive, filler, lubricant, and binder. A pharmaceutical composition is provided that contains one or more pharmaceutically acceptable ingredients, wherein the N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide is at least 90%, preferably at least 95%, amorphous. Preferably, the pharmaceutical composition is formulated for oral administration.

[0044] The present invention further provides a method for treating orthopoxvirus infection or eczema vaccinia, comprising administering to a patient in need of treatment a therapeutically effective amount of purified amorphous N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-2-(2-hydroxybenzoate)-2-(2-methylbenzoate ... wherein at least 90%, preferably at least 95% of the N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide is amorphous.

[0045] Formulation and Administration Formulations of amorphous ST-246 can be prepared by processes known in the art of pharmaceutics. The following examples (infra) are provided to enable those skilled in the art to more clearly understand and to practice the present invention. They should not be considered as limiting the scope of the invention, but merely as being illustrative and representative thereof.

[0046] The amorphous salts of the present invention can be administered in a variety of oral and parenteral dosage forms. Oral dosage forms can be tablets, coated tablets, hard and soft gelatin capsules, solutions, emulsions, syrups, or suspensions. Parenteral administration includes intravenous, intramuscular, intradermal, subcutaneous, intraduodenal, or intraperitoneal administration. In addition, the salts of the present invention can be administered transdermally (which may contain a penetration enhancer), buccal, nasal, and suppository routes.

[0047] For preparing pharmaceutical compositions from the compound of the present invention, pharmaceutically acceptable carrier can be either solid or liquid.Solid form preparations include powder, tablets, pills, hard and soft gelatin capsules, cachets, suppositories and dispersible granules.Solid carrier can be one or more substances, which can also act as diluent, flavoring agent, lubricant, suspending agent, binder, preservative, tablet disintegrating agent or encapsulating material.

[0048] In powders, the carrier is a finely divided solid that is in admixture with the finely divided active ingredient. In tablets, the active ingredient is mixed with a carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired.

[0049] Suitable excipients for tablets, coated tablets, and hard gelatin capsules include, for example, microcrystalline cellulose, lactose, corn starch and its derivatives, magnesium carbonate, magnesium stearate, sugar, lactose, pectin, dextrin, starch, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, talc, and fatty acids or their salts, such as stearic acid. If desired, tablets or capsules may be enteric-coated or sustained-release formulations. Suitable excipients for soft gelatin capsules include, for example, vegetable oils, waxes, fats, semisolid and liquid polyols. Liquid form preparations include solutions, suspensions, retention enemas, and emulsions. For parenteral injection, liquid preparations can be formulated in solution, water, or water / polyethylene glycol solution.

[0050] Aqueous solutions suitable for oral use can be prepared by dissolving the active ingredient in water and adding suitable colorants, flavors, stabilizing, and thickening agents, as desired. Aqueous suspensions suitable for oral use can be prepared by dispersing the finely divided active ingredient in water with a viscous material, such as natural or synthetic gums, resins, methylcellulose, sodium carboxymethylcellulose, and other well-known suspending agents.

[0051] The compositions may also contain, in addition to the active ingredient, colorants, flavors, stabilizers, buffers, artificial and natural sweeteners, dispersants, thickeners, preservatives, wetting agents, emulsifiers, salts for adjusting osmotic pressure, masking agents, antioxidants, and the like.

[0052] The compounds of the invention can be administered intravenously in saline (e.g., buffered to a pH of about 3 to 8). Conventional buffers, such as phosphate, bicarbonate, or citrate, can be used in the compositions.

[0053] Also included are solid form preparations, which are intended to be converted into liquid form preparations for oral administration shortly before use.Such liquid forms include solutions, suspensions, and emulsions.For preparing suppositories, suitable excipients include natural and hardened oils, waxes, fatty acid glycerides, semi-liquid or liquid polyols.The molten homogeneous mixture is then poured into conveniently sized molds, allowed to cool, and thereby solidify.Suitable pharmaceutical carriers, excipients, and their formulations are described in Remington: The Science and Practice of Pharmacy 1995, edited by EW Martin, Mack Publishing Company, 19th edition, Easton, PA.

[0054] Dosages can vary within wide limits and will, of course, be adjusted in each particular case according to the individual needs of the patient and the severity of the condition being treated. Typical preparations contain from about 5% to about 95% active compound (w / w). For oral administration, a daily dose of between about 0.01 and about 100 mg / kg body weight / day should be appropriate in monotherapy and / or in combination therapy. Preferred daily doses are from about 0.1 to about 300 mg / kg body weight, more preferably 1 to about 100 mg / kg body weight, and most preferably 1.0 to about 50 mg / kg body weight / day.

[0055] Generally, treatment is initiated with a lower dose, which is less than the optimal dose of the compound. Thereafter, the dose is gradually increased until the optimal effect under the circumstances is reached. The daily dose can be administered in a single dose or in divided doses, typically 1 to 5 doses per day.

[0056] Pharmaceutical preparations are preferably in unit dosage form.In this form, the preparation is divided into unit doses containing appropriate amounts of active ingredients.The unit dosage form can be a packaged preparation, and the package contains discrete amounts of preparations, such as packed tablets, capsules, and powders in vials or ampoules.Also, the unit dosage form can be a capsule, tablet, cachet, or lozenge itself, or any of these in package form in appropriate number.

[0057] Appropriate dosages will be readily appreciated by those skilled in the art. It will be appreciated that the amount of the polymorph of the invention required for use in therapy will vary with the nature of the condition being treated and the age and condition of the patient, and will ultimately be at the discretion of the attending physician or veterinarian. The polymorph of the invention can be used in combination with other antibacterial agents, such as penicillins, cephalosporins, sulfonamides, or erythromycin.

[0058] The above-mentioned combinations may conveniently be presented for use in the form of pharmaceutical formulations, and pharmaceutical formulations comprising a combination as defined above, together with a pharmaceutically acceptable carrier or excipient, thus constitute a further aspect of the invention. The individual components of such combinations may be administered by any convenient route, either sequentially or simultaneously, in separate or combined pharmaceutical formulations.

[0059] When administration is sequential, either the amorphous ST-246 compound of the invention or the second therapeutic agent can be administered first. When administration is simultaneous, the combination can be administered in the same or different pharmaceutical compositions.

[0060] Using the routes and methods of administration and dosages described above and dosage forms described herein below, the amorphous form of ST-246 of the present invention can be used to prevent and treat various diseases and conditions in humans. By way of example, and not limitation, in the case of orthopoxvirus infections and related diseases, this can be achieved by administering to a patient suffering from an orthopoxvirus infection in need of such treatment a composition comprising amorphous ST-246 (substantially free of polymorphic forms or mixtures of polymorphs) and an inert carrier or diluent, said composition being administered in an amount effective to prevent or treat said viral infection.

[0061] According to this invention, amorphous ST-246 (substantially free of polymorphic forms or mixtures of polymorphs) is administered in an amount effective to prevent or treat orthopoxvirus infection. Any effective amount of such amorphous form (substantially free of polymorphic forms or mixtures of polymorphs) required to prevent or treat such viral infection may be used in this composition. Generally, for oral dosage forms, a dose of about 0.5 mg / kg to about 5.0 mg / kg of body weight / day is used. However, the amount of such amorphous form (substantially free of polymorphic forms or mixtures of polymorphs) in the administered oral unit dose will vary depending on the state of the viral infection and the patient's weight, and, of course, is at the discretion of the physician.

[0062] In accordance with this invention, an oral unit dosage form containing a given amorphous form (substantially free of polymorphic forms or mixtures of polymorphs) can be administered at a dose of preferably about 30 mg to about 800 mg / day, more preferably about 50 mg to about 600 mg / day, and most preferably about 300 mg or 400 mg / day, once to three times daily, or as needed.

[0063] In some embodiments of the invention, the amorphous forms of the present invention can also be used in combination with: (1) vaccines; (2) cidofovir, an injectable antiviral drug (an acyclic nucleoside phosphonate, and thus treats eczema vaccinatum (EV), a life-threatening complication of vaccinia virus infection, and other related disorders, independent of phosphorylation by viral enzymes); and / or (3) CMX001 (hexadecyloxypropyl-cidofovir), a mimetic of the naturally occurring lipid, lysolecithin, formed by linking the lipid, 3-hexadecyloxy-1-propanol, to the phosphonic acid group of cidofovir.

[0064] The invention also provides a pharmaceutical pack or kit comprising one or more containers filled with ST-246 in amorphous form, optionally having associated with it a notice in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, the notice reflecting approval by the agency of the manufacture, use or sale for human administration.

[0065] Example 1: Preparation of amorphous ST-246 by melting and quenching Approximately 20 g of ST-246 monohydrate (polymorphic form I) was dehydrated in a desiccator with Drierite under vacuum in a drying oven at 50° C. for 2 days to obtain dehydrated ST-246.

[0066] In a glove box, under a nitrogen atmosphere (RH<5%), 5.2 g of dehydrated ST-246 was weighed into a beaker and heated in a silicone oil bath while maintaining the bath temperature at 215°C for 5 minutes or until the material was completely melted. The beaker was removed from the silicone oil bath and immediately quenched by immersion in liquid nitrogen. The beaker was kept in liquid nitrogen for 1 minute and then immediately transferred to a glove box under a nitrogen atmosphere (RH<5%). The product was transferred from the glass beaker to a 10 mL amber glass bottle and sealed with a PTFE-lined cap. This was stored in a freezer at -20°C. The product was pale yellow in color, and the yield was 5.1 g.

[0067] The quenched ST-246 was characterized using the following analyses: water content by Karl Fischer titration, polarized light microscopy, purity by HPLC, and XRPD. The water content of the product was measured at 0.09%. A sample of the final product showed no birefringence under polarized light, indicating that the product was amorphous. Purity was 99.1% by HPLC (area % at 224 nm). Finally, the XRPD diffractogram showed a peakless halo pattern, indicating that the product was amorphous.

[0068] Example 2: Preparation of amorphous ST-246 by melting Approximately 5.0 g of ST-246 monohydrate was weighed into a 25 mL Pyrex test tube and placed in an ambient temperature silicone oil bath. The silicone oil bath was heated to 210°C for 2 hours. A low flow of nitrogen was delivered to the test tube using Tygon tubing during the heating process. When the oil bath temperature reached 202°C, the ST-246 began to melt. When the oil bath temperature reached 210°C, the ST-246 melted to a clear, colorless liquid. The ST-246 was then removed from the heat, and the test tube was immediately placed in an ice bath and held there for 5 minutes while a low flow of nitrogen was continued to bubble through the test tube. It was then removed from the ice bath and transferred to a glove box under a nitrogen atmosphere (<10% RH). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. It was stored in a freezer at -20°C. The product was a glassy, ​​colorless solid.

[0069] The product was analyzed for purity, which was 97.9% by HPLC.

[0070] Example 3: Preparation of amorphous ST-246 by melting and quenching Approximately 2.00 g of ST-246 monohydrate was added to a steel beaker and placed in a room-temperature silicone oil bath. The oil bath was heated and stirred using a stirring hotplate. The heated oil bath temperature reached 160°C over 2 hours and increased to 205°C over 25 minutes. Once the bath temperature reached 205°C, the ST-246 began to gradually melt. The bath temperature then increased to 215°C over the next 20 minutes. Once the oil bath temperature reached 215°C, the ST-246 was completely melted. The beaker was then removed from the oil bath and placed in liquid nitrogen for approximately 1 minute. The product inside the beaker was yellow and immediately hardened. The beaker containing the product was then placed in a glove box under a nitrogen atmosphere (relative humidity less than 10%). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. The yield was 1.8 g of product. The product was a yellow glass. It was stored in a freezer at -20°C. The purity was 98.1% by HPLC (area % at 224 nm). The XRPD diffractogram showed a peakless halo pattern, indicating that the product was amorphous.

[0071] Example 4: Preparation of amorphous ST-246 spray-dried dispersion with PVP Approximately 2.0 g of ST-246 monohydrate and 4.0 g of Kollidon 30 (PVP) were dissolved in 45 mL of methanol, and the resulting solution was spray dried using a Buchi B290 Mini Spray Dryer and a Buchi B-295 Intert Loop set to the following parameters: Aspirator: 100%; Nitrogen flow rate: 30m 3 / hr; feed rate: 30%; and inlet temperature: 65°C.

[0072] The resulting product was a white, fluffy powder. The purity was 99.9% by HPLC (area % at 224 nm). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. This was stored in a freezer at -20°C. The XRPD diffractogram showed a peakless halo pattern, indicating that the product was amorphous.

[0073] Example 5: Preparation of Amorphous ST-246 Spray-Dried Dispersion with HPMCAS-M Approximately 0.50 g of ST-246 monohydrate and 4.50 g of HPMCAS-M were dissolved in approximately 300 mL of 95:5 THF:water (v / v). The solution was then spray dried using a Buchi B290 Mini Spray Dryer and a Buchi B-295 Intertroop set to the following parameters: Aspirator pressure: 100%; nitrogen flow rate: 40 m 3 / hr; feed rate: 40%; and inlet temperature: 60°C.

[0074] The product was a white, fluffy powder with a purity of 99.8% by HPLC (area % at 224 nm). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. This was stored in a freezer at -20°C. The XRPD diffractogram showed a peakless halo pattern, indicating that the product was amorphous.

[0075] Example 6: Preparation of amorphous ST-246 spray-dried dispersion with HPMC Approximately 4.50 g of (hydroxypropyl)methylcellulose (viscosity 2600-5600 cp) was dissolved in approximately 400 mL of THF and 100 mL of water. In a separate flask, approximately 0.50 g of ST-246 monohydrate was dissolved in 10 mL of THF. The ST-246 solution was added to the HPMC solution. The resulting solution was spray dried using a Buchi B290 Mini Spray Dryer and a Buchi B-295 Inert Loop set to the following parameters: Aspirator: 100%; Nitrogen flow rate: 40m 3 / hr; feed rate: 40%; and inlet temperature: 65°C.

[0076] The product was a white, fluffy powder with a purity of 99.8% by HPLC (area % at 224 nm). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. This was stored in a freezer at -20°C. The XRPD diffractogram showed a peakless halo pattern, indicating that the product was amorphous.

[0077] Example 7: Preparation of amorphous ST-246 by hot melt extrusion (HMS) with PEG-4000 Approximately 4.0 g of poly(ethylene glycol) mw4000 was transferred into a 125 mL steel beaker and placed on a stirring hotplate set at 150°C while stirring. The PEG4000 rapidly melted. Approximately 1.0 g of ST-246 monohydrate was then added, and stirring was continued for 10 minutes while covered. The temperature was then increased to 175°C. After 30 minutes of stirring at 175°C, a clear solution was obtained. The solution was removed from the heat and immediately placed in a beaker in liquid nitrogen and held there for approximately 2 minutes.

[0078] The product was a white translucent glass with a purity of 99.7% by HPLC (area % at 224 nm). The product was then transferred to an amber glass bottle and sealed with a PTFE-lined cap. This was stored in a freezer at -20°C. The XRPD diffractogram in Figure 1 showed significant defect peaks, indicating the product was a disordered crystalline material or mesophase.

[0079] All references cited herein are hereby incorporated by reference in their entirety for all purposes.

[0080] While the invention has been described in terms of its preferred embodiments, it is of broader applicability as will be understood by those skilled in the art, the scope of which is limited only by the claims that follow.

Claims

1. A method for producing an amorphous solid dispersion of N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, said method comprising: (a) preparing a liquid solution comprising N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl)-benzamide, at least one polymer, and a solvent; and (b) spray drying said liquid solution to thereby produce said amorphous solid dispersion. A method comprising the above steps.

2. The method according to claim 1, wherein said liquid solution comprises at least one solvent selected from the group consisting of tetrahydrofuran, alcohol, ethyl acetate, methyl ethyl ketone, dichloromethane, water, and mixtures thereof.

3. The method according to claim 1, wherein said polymer is selected from the group consisting of methacrylic acid copolymers, hydroxypropylmethylcellulose (HPMC), HPMCP-H55, CAP, PVAP, HP-MCAS-L, HP-MCAS-M, HP-MCAS-H, hypromellose, povidone, copovidone, HPC, poloxamer, PVP-VA, PVP (neutral), croscarmellose, methocel, ethocel, plaidon, and mixtures thereof.

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