1 la, 1 lb, 12, 13, 13a-OCTADECAHYDRO-2H-CYCLOPENTA[a]CHRYSEN-9-YL)OXY)-2,2-

DIMETHYL-4-OXOBUTANOIC ACID

FIELD OF THE INVENTION

The present invention provides ionic liquid salts of 4- (((3aR,5aR,5bR,7aR,9S,l laR,l lbR,13aS)-3a-((R)-2-((4-chlorobenzyl)(2- (dimethylamino)ethyl)amino)-l-hydroxyethyl)-l-isopropyl-5a,5 b,8,8,l la-pentamethyl-2-oxo- 3, 3a, 4, 5, 5a, 5b, 6, 7, 7a, 8, 9, 10, 11, 1 la, 1 lb, 12, 13, 13a-octadecahydro-2H-cyclopenta[a]chry sen-9- yl)oxy)-2,2-dimethyl-4-oxobutanoic acid. These ionic liquid salts can be incorporated into novel compositions and pharmaceutical compositions that are useful for the treatment of HIV infections in patients having an HIV infection or AIDS. The present invention relates to such ionic liquid salt forms, to compositions (e.g., pharmaceutical compositions) thereof, and methods of making and using the compounds and compositions.

BACKGROUND OF THE INVENTION

The human immunodeficiency virus (HIV) is a retrovirus that causes the infection of HIV in the human immune system. Over time, an untreated HIV infection leads to acquired immunodeficiency syndrome (AIDS) through the destruction of the human immune system. ( HIV Tutorial, library.med.utah.edu, http://library.med.utah.edu/WebPath/TUTORlAL/AIDS/HIV.html.) HIV and AIDS are still a major public health threat and can cause death through the opportunistic infections that result from AIDS. The World Health Organization reports 36.7 million people are living with HIV/ AIDS worldwide and 1.1 million people died of AIDS-related illnesses in 2015.

( HIV/AIDS , World Health Organization, http://www.who.int/hiv/en ). HIV and AIDS were unknown until the early 1980’s but since have spread around the world to infect millions of people There is currently no vaccine to prevent HIV infection but only antiretroviral treatments to extend the lives of those infected.

HIV infects T4 lymphocytes in the human immune system. The immune response in the human body produces HIV antibodies and cytotoxic lymphocytes to induce the immune system to respond and seek out and destroy invading vimses or bacteria. However, once the lymphocyte becomes infected with HIV, the vims is able to replicate increasing its ability to kill T4 cells. As the number of T4 lymphocytes are infected by HIV, the body’s immunity system is compromised and becomes more susceptible to opportunistic infections. There is no known cure for AIDS, but advancement in treatment delays the onset of symptoms and prolongs the lives of those infected with HIV. {HIV & Aids, Microbiology Online,

http://www .microbiologyonline. org. uk/media/transfer/doc/factfile _hiv_aids.pdf. )

Highly active antiretroviral therapy (HAART) is also an existing treatment that combines several antiretroviral medicines to slow the rate of HIV- 1 replicating in the body. This combination of antiretroviral medicines includes nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), Protease inhibitors (Pis), entry inhibitors, and integrase inhibitors. However, the combination of antiretroviral medicines over a prolonged period may lead to drug resistance. {Catherine S. Adamson, Karl Salzwedel, and Eric O. Freed, Virus Maturation as a Novel HIV-1 Therapeutic Target, Expert Opinion on Therapeutic Targets (Aug. 2009), https://www.ncbi. nlm. nih.gov/pmc/articles/PMC2737327.

Therefore, what is needed are newer classes of HIV antiviral medicines that, along with HAART, can reduce the likelihood of developing drug resistance over prolonged periods of administration. One such newer class, are maturation inhibitors. Maturation inhibitors interfere at a late stage of viral replication, blocking protease cleavage. Betulin is a naturally occurring maturation inhibitor, which is a class of antiviral drugs for the treatment of HIV. See Published PCT Application No. WO 2013/090664. Maturation inhibitors are unlike the existing protease inhibitors class of HIV drugs due to their ability to bind the group-specific antigen (gag) protein, and not the protease.

Maturation inhibitors binding the gag protein leads to the formation of noninfectious, immature vims particles, incapable of infecting other cells. This then leads to the release of immature HIV particles that cannot complete their life cycle and thus, are not infectious. {Abdul A. Waheed, Eric O. Freed, HIV Type 1 Gag as a Target for Antiviral Therapy, AIDS Research and Human Retroviruses (Jan. 2012), https://www .ncbi.nlm.nih.gov/pmc/articles/PMC3251841. ) Since maturation inhibitors bind the gag protein and not the protease, they are able to retain inhibitory activity against HIV infections with resistance. There is a continuing need for chug options and maturation inhibitors open a new class of antiretroviral therapeutics.

One particular maturation inhibitor having the chemical name, 4- (((3aR,5aR,5bR,7aR,9S,l laR,l lbR,13aS)-3a-((R)-2-((4-chlorobenzyl)(2- (dimethylamino)ethyl)amino)-l-hydroxyethyl)-l-isopropyl-5a,5 b,8,8,l la-pentamethyl-2-oxo- 3, 3a, 4, 5, 5a, 5b, 6, 7, 7a, 8, 9, 10, 11, 1 la, 1 lb, 12, 13, 13a-octadecahydro-2H-cyclopenta[a]chry sen-9- yl)oxy)-2,2-dimethyl-4-oxobutanoic acid (‘Compound A’ herein), is currently in phase II clinical trials for the treatment of HIV infections. This compound is disclosed, for example, in U.S. Patent No. 9,102,685 (published PCT Application No. WO 2013/090664A1).

Ionic liquid salts are essentially salts of a compound that have a melting point at or below room temperature. A benefit of a liquid ionic salt over a typical suspension of a solid form of Compound A is to design out the Compound A particle settling risk. This particle settling can lead to caking, particle growth and/or agglomeration which can translate to resuspension issues or clogging of the syringe when attempting to administer by injection. Another benefit of a liquid ionic salt over a typical suspension of a solid form of Compound A is the potential to create highly concentrated liquid injectable formulations which exceed the typical maximum concentrations that can be achieved by a typical suspension which has a maximum of 150 - 250 mg/mL. As the concentration increases, the volume required to inject the appropriate dose of Compound A decreases which may translate to a less painful injection and a patient benefit. Alternatively, an ionic liquid salt created from two active substances that both individually treat HIV could create a highly concentrated fixed dose combination injection rather than having two separate injections thus again reducing the burden on the patient. Ionic liquid salts can also act as a vehicle for a second HIV medication to create a fixed dose combination. Ionic liquid salts are not widely used in the pharmaceutical industry in formulation development, which tends to focus on solid-state forms (amorphous or crystalline) of compounds. The primary use of ionic liquid salts has been in alternate solvent systems given their ability to readily dissolve many substances. Liquid ionic salts of Compound A are important as they could lead to new pharmaceutical compositions and formulations for the purpose of inhibiting HIV replication and treating HIV patients.

Ionic liquids are not prevalent in the pharmaceutical industry and are not used to our knowledge as long acting injectable formulations. However, in recent years there have been more and more articles regarding using ionic liquids in pharmaceutical development. Robin Rogers, one of the leading ionic liquid researchers, has written several articles that give comprehensive reviews of ionic liquids.

The ionic liquid salts provide alternative forms of Compound A and formulated versions of the ionic liquid salts, may have one or more desirable properties, such as improved stability (e.g. physical, thermal and/or chemical), improved solubility, ability to control release rates, enhanced efficacy, enhanced permeability, and/or ease of use, manufacture, and/or delivery. Such benefits may include avoidance of particle growth, suspension settling, resuspension challenges, particulate clogging of syringes, reduced pharmacokinetic (PK) variability, reduction in injection volume compared to solid form, amongst others. In-vivo benefits may include greater initial dispersion of the formulation compared to a suspension of the solid form of Compound A which reduces the palpation of the injection site and potential pain. Greater dispersion also increases surface area and could increase PK profile/exposure.

SUMMARY OF THE INVENTION

Briefly, in one aspect, the present invention discloses ionic liquid salts of the compound 4- (((3aR,5aR,5bR,7aR,9S,l laR,l lbR,13aS)-3a-((R)-2-((4-chlorobenzyl)(2- (dimethylamino)ethyl)amino)-l-hydroxyethyl)-l-isopropyl-5a,5 b,8,8, l la-pentamethyl-2-oxo- 3, 3a, 4, 5, 5a, 5b, 6, 7, 7a, 8, 9, 10, 11, 1 la, 1 lb, 12, 13, 13a-octadecahydro-2H-cyclopenta[a]chry sen-9- yl)oxy)-2,2-dimethyl-4-oxobutanoic acid, shown below as the compound of Formula (I). This compound will be referred to as the compound of Formula (I) or as Compound A

Formula (I)

In another aspect, the present invention discloses pharmaceutical compositions comprising an ionic liquid salt of Compound A.

In another aspect, the present invention provides a method for treating HIV comprising the administration of an ionic liquid salt of Compound A.

In another aspect, the present invention provides a method for the preparation of ionic liquid salts of Compound A comprising the steps of 1) creating the ionic liquid salt followed by 2) combining additional components, such as viscosity reducing agents, with the ionic liquid salt.

In another aspect, the present invention provides a method for the preparation of ionic liquid salts of Compound A comprising the steps of 1) combining Compound A, the counter ion, and additional components, such as viscosity reducing agents, with an appropriate solvent, and 2) subsequently removing the solvent. In this process the ionic pair of Compound A and the counter ion is formed in the presence of the additional components, such as the viscosity reducing agents.

In another aspect, the present invention provides an ionic liquid salt of Compound A for use in therapy.

In another aspect, the present invention provides use of an ionic liquid salt of Compound A thereof in the manufacture of a medicament for use in treating HIV.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is the average pharmacokinetic profile from intramuscular injection in rats of a formulated glutaric acid ionic liquid containing Compound A at 182mg/mL compared to both an aqueous drug particle suspension containing Compound A at 188 mg/mL and a polymer matrix drug loaded implant, dosed at 20mg/kg intramuscular for the formulated ionic liquid and aqueous suspension and administered subcutaneously for the implant.

Figure 2 is the individual pharmacokinetic profile from intramuscular injection in rats of a formulated glutaric acid ionic liquid containing Compound A at 182mg/mL, dosed at 20mg/kg intramuscular.

Figure 3 is a representative injection site depot harvested from rats 1 month post injection of a formulated glutaric acid ionic liquid containing Compound A at 182mg/mL, dosed at 20mg/kg intramuscular

Figure 4 is a representative injection site depot harvested from rats 1 month post injection of an aqueous drug particle suspension containing Compound A at 188 mg/mL, dosed at 20mg/kg intramuscular.

Figure 5 is the rheological evaluation of the viscosity of a formulated lactic acid based ionic liquid where PEG200 is the viscosity reducing agent, at different concentrations of Compound A.

Figure 6 is the average pharmacokinetic profile from intramuscular injection in beagle dogs of a formulated lactic acid ionic liquid containing Compound A at 300mg/mL, dosed at 5mg/kg intramuscular

Figure 7 is the individual pharmacokinetic profile from intramuscular injection in beagle dogs of a formulated lactic acid ionic liquid containing Compound A at 300mg/mL, dosed at 5mg/kg intramuscular

DETAILED DESCRIPTION OF THE INVENTION

The ionic liquid salts of Compound A have at least one ionizable group, and at least one counter ion. Preferably, the counterion is an acidic group. More preferably, the counterion comprises an asymmetric organic acid. Preferred counterions comprise, for example, Thymine- 1- acidic acid, glucuronic acid, ascorbic acid, gentisic acid, D-glucuronic acid, R-(-)-mandelic acid, hippuric acid, shikimic acid, glutaric acid, sorbic acid, lactic acid, and hexadecylamine. For example, in certain embodiments, the counterion is selected from the group consisting glutaric acid and hexadecylamine.

A particularly preferred liquid ionic liquid salt of Compound A is a lactic acid salt and is illustrated below in Formula (IA).

Formula (IA)

Preferably, the ionic liquid salts of Compound A are prepared with an excess of the counter ion on a molar basis. Preferably, the molar ratio of the salt counter ion to Compound A ranges from 10: 1 to 1: 1. More preferably the molar ratio of the salt counter ion to Compound A ranges from 3 : 1 to 1:1.

Preferably, the pharmaceutical compositions of this invention comprise compounds that act to reduce the viscosity (“a viscosity reducer”). Viscosity reduction is a critical factor because compositions of ionic liquid salts of Compound A mentioned that do not comprise a viscosity reducer, typically have a viscosity above 1000 centipoise which is too high to be further processed or injected. In addition, after these ionic liquid salts have been formed, it is difficult to add a second liquid because of the high viscosity and unique behavior of the ionic liquid. Therefore, the optimal approach to create the formulated ionic liquid is to choose a viscosity reducer that is not only compatible with the final components of the formulated ionic liquid but also miscible with the process solvent used to manufacture the ionic liquid. It is also preferable that the viscosity reducer does not inhibit the formulation of the ionic liquid. Preferred viscosity reducers, for example, include oligomers and polymers, such as polyethylene glycol (PEG). Viscosity reducers can also be oils, such as seasame oil, solvents, such as DMSO, ethanol, methanol or NMP, surfactants, such as poloxamers, polysorbates, lecithin, etc. and various mixtures thereof. Particularly preferred viscosity reducers are PEG with an average molecular weight below 4000 daltons. In one embodiment, the viscosity reducer comprises PEG-200. Preferably, the pharmaceutical compositions of this invention comprise viscosity reducer in a weight % of from 10% to 90% of the pharmaceutical formulation. More preferably, the pharmaceutical compositions of this invention comprise viscosity reducer in a weight % of from 50% to 80% of the pharmaceutical formulation.

Preferably, the pharmaceutical compositions of this invention are suitable for injection.

As with all pharmaceutical compounds and compositions, chemical and physical properties of the Compound A ionic liquid and formulated ionic liquids are important in its commercial development as a novel HIV therapeutic. These properties include, but are not limited to: (1) density, viscosity and hygroscopicity, (2) thermodynamic properties such as melting temperature, (3) kinetic properties such as dissolution rate and stability (including stability at ambient conditions, especially to moisture, and under storage conditions), (4) surface properties such as interfacial tension (5) mechanical properties such as handling, flow; and (6) filtration properties. These properties can affect, for example, processing and storage of pharmaceutical compositions comprising the Compound A ionic liquid and formulated ionic liquids.

A preferred method for the preparation of ionic liquid salts of Compound A comprises the steps of 1) combining Compound A, the counter ion, and additional components, such as viscosity reducing agents, with an appropriate solvent, and 2) subsequently removing the solvent. In this process the ionic pair of Compound A and the counter ion is formed in the presence of the additional components, such as the viscosity reducing agents. Preferred solvents include ethanol and methanol.

The method of this invention for treating HIV may also include the administration of an additional agent active against an HIV vims, wherein said agent active against the HIV vims is selected from the group consisting of Nucleotide reverse transcriptase inhibitors; Non-nucleotide reverse transcriptase inhibitors; Protease inhibitors; Entry, attachment and fusion inhibitors; Integrase inhibitors; Maturation inhibitors; CXCR4 inhibitors; and CCR5 inhibitors.

US Patent No. 9,102,685 describes the Compound A, its HIV maturation inhibitor properties, and its antiviral use, especially against HIV infections. Compound A is currently under evaluation and investigation as an anti-HIV pharmaceutical agent, in particular, as an HIV maturation inhibitor. There exists a need for the compound to be prepared in a form suitable for large scale manufacture, and for ease of formulating into an acceptable product for administration to humans.

EXAMPLES

We have found that lactic acid and glutaric acid ionic liquid salts of Compound A, when prepared in a molar ratio of about 2: 1 in the presence of PEG200 have suitable stability to be developed as a long acting injectable product suitable for administration to humans. The lactic acid ionic liquid salt of Compound A formulated with PEG 200 was suitable for sterile filtration and injection through at least a 23 gauge needle. In addition, the in-vivo pharmacokinetic profile in animals maximized the exposure compared to other long acting injectable formulations that were attempted.

Amorphous Compound A can be prepared, for example, as disclosed in US 9,102,685. Preparation of Compound A Lactic Acid ionic liquid salt. The respective ratios of Compound A and counter-ions were mixed together with a solvent (ethanol, methanol, protic solvent) in a suitable container for at least 2 hours. Various counter-ions were evaluated as shown in the table below at various molar ratios.

Then the solvent is removed (via vacuum oven or rotary evaporator) producing a set of ionic liquids for further formulation. A viscosity reducer can be added prior to solvent removal to reduce the viscosity of the ionic liquid.

In this example, 9 grams of Compound A and 2 grams of lactic acid are added to 65 grams of ethanol in a suitable container and the mixture was stirred for 2hrs. Then the solvent is removed (via vacuum oven or rotary evaporator) producing the final formulated ionic liquid.

Preparation of Compound A Glutaric Acid ionic liquid salt in the presence of PEG200

150 milligrams of Compound A and 25 milligrams of glutaric acid are added to 1.4 grams of ethanol and 0.22 grams of PEG200 in a suitable container and the mixture was stirred for 2hrs. Then the solvent is removed (via vacuum oven or rotary evaporator) producing the final formulated ionic liquid.

The average pharmacokinetic profile from an injection of the formulated glutaric acid with PEG200 example is shown in Figure 1 compared to an injection of an aqueous based drug particle suspension of Compound A and a polymer matrix drug loaded implant. The individual pharmacokinetic profiles of the formulated glutaric acid with PEG200 ionic liquid of Compound A is shown in Figure 2.

The 1 -month formulated ionic liquid PK results show increased exposure over the other long acting products at the same dose strength. Additionally, at the end of this study, the muscle containing the injection site depots were harvested from the rats for the formulated ionic liquid (Figure 3) and the aqueous dmg particle suspension (Figure 4). The depots were clearly visible and revealed a more diffuse depot for the formulated ionic liquid in contrast to the aqueous drug particle suspension.

Preparation of Compound A Glutaric Acid ionic liquid salt in the presence of PEG200

158 milligrams of Compound A and 29.6 milligrams of glutaric acid are added to 2.13 grams of ethanol and 0.34 grams of PEG200 in a suitable container and the mixture was stirred for 2hrs. Then the solvent is removed (via vacuum oven or rotary evaporator) producing the final formulated ionic liquid.

Preparation of Compound A Lactic Acid ionic liquid salt in the presence of PEG200

9 grams of Compound A and 2 grams of lactic acid are added to 65 grams of ethanol in a suitable container. Finally, 24 grams of PEG200 were added and the mixture was stirred for 2hrs. Then the solvent is removed (via vacuum oven or rotary evaporator) producing the final formulated ionic liquid.

The preparation above was also formulated with different quantities of PEG200 to understand the relationship between the viscosity (cP) and the final concentration of Compound A. This relationship is summarized in Figure 5.

The preparation above was also sterile filtered with a 0.22 micron filter and injected intramuscularly in beagle dogs. The average pharmacokinetic profile is shown Figure 6 and the individual pharmacokinetic profiles are shown in Figure 7.