Patent Description:
The need to improve the bioavailability, pharmacokinetics, pharmacodynamics, tissue distribution, cytotoxicities, and interval dosing of antiretroviral therapy (ART) in the treatment of human immunodeficiency virus (HIV) infection is notable (<NPL>; <NPL>; <NPL>). Since the introduction of ART, incidences of both mortality and co-morbidities associated with HIV-<NUM> infection have decreased dramatically. However, ART limitations abound which prevent full suppression of viral replication, reductions in drug- resistance patterns, biodistribution, pharmacokinetics (PK) and associated morbidities in HIV-infected individuals. These limitations also include drug PK and biodistribution, (<NPL>; <NPL>; <NPL>). Moreover, despite effective drug combinations, HIV continues to replicate at low levels in reservoir sites that include, but are not limited to, the lymph nodes, bone marrow, gut-associated lymphoid tissues, spleen and central nervous system (<NPL>; <NPL>). Such limitations affect pathways towards sterilization/eradication of HIV-<NUM> infection from an infected human host.

Since antiretroviral drugs (ARVs) are quickly eliminated from the body and do not thoroughly penetrate all organs, dosing schedules tend to be complex and involve the continuous administration of large amounts of drug. Patients have difficulty properly following therapy guidelines leading to suboptimal adherence and increased risk of developing viral resistance, which can result in treatment failure and accelerated progression of disease (<NPL>). For HIV-infected patients who also experience psychiatric and mental disorders and/or drug abuse, proper adherence to therapy is even more difficult (<NPL>; <NPL>). While long-acting injectable formulations of rilpivirine and cabotegravir (CAB-LAP) have allowed for once-monthly injection for HIV suppression and prevention (<NPL>; <NPL>; <NPL>),these therapies still require high doses and high injection volumes.

<NPL> discloses lipid-based carriers for prodrugs to enhance delivery. Specifically, this article discloses prodrugs designed to target specific sites either via selective adsorption, retention or release of active drug at the target site. <CIT> discloses prodrugs of integrase inhibitors.

Accordingly, there is a need for drug delivery systems that optimize cell uptake and retention, improve intracellular stability, reduce injection volumes, extend drug release, extend plasma half-life, maintain antiretroviral efficacy, and limit cytotoxicity.

Treatments of viral infections, particularly HIV infections, which are currently available, include inhibitors of viral entry, nucleoside reverse transcriptase, nucleotide reverse transcriptase, integrase, and protease. Resistance is linked to a shortened drug half-life, the viral life cycle, and rapid mutations resulting in a high genetic variability. Combination ART which are considered "cocktail" therapy, have gained substantial attention. Benefits include decreased viral resistance, limited toxicities, improved adherence to therapeutic regimens and sustained antiretroviral efficacy. Combination therapies minimize potential drug resistance by suppressing viral (e. , HIV) replication, thereby reducing spontaneous resistant mutants. Treatment failure is attributed, in part, to the short drug half-life. Furthermore, failure can also be attributed, in part, to limited access to tissue and cellular viral reservoirs, thereby precluding viral eradication efforts. To these ends, the development of cell and tissue targeted nanoformulated prodrug (nanoparticle) platforms are of considerable interest in the management of viral (e. , HIV) infections. Pre-exposure prophylaxis (PrEP) is another strategy used in the management of viral (e. , HIV) transmission. For example, TRUVADA® (tenofovir/emtricitabine) has been approved for pre-exposure prophylaxis against HIV infection. Additionally, the combination of lamivudine and zidovudine (COMBIVIR®) has been used as pre-exposure prophylaxis and post-exposure prophylaxis.

Traditional dosage forms of ARVs are characterized by high pill burden that lead to poor adherence. Targeted prodrug nanoparticles will improve drug biodistribution and enhance the therapeutic efficacy and the lower dosage will reduce side effects such as systemic toxicity. Further, single drug treatments may cause high genetic variability of HIV and drug resistance. In contrast, targeted combination therapeutic strategies will decrease viral resistance, improve the quality of life, and increase survival time.

The prodrugs and nanoformulated prodrugs (nanoparticles) provided herein have numerous superior properties including, without limitation, extended drug half-life, increased hydrophobicity, improved protein binding capacity, improved biodistribution, improved plasma half-life, and increased antiviral efficacy. This will benefit people who have to receive daily high doses or even several doses a day, since lower dosage with less dosing frequency would not only decrease the side effects, but also be convenient to the patients. The prodrugs and nanoformulated prodrugs (nanoparticles) provided herein may also be used as a post-exposure treatment and/or pre-exposure prophylaxis (e. , for people who are at high risk of contracting HIV-<NUM>). In other words, the prodrugs and nanoparticles as described herein and their combination may be used to prevent a viral infection (e. , HIV infection) and/or treat or inhibit an acute or long term viral infection (e. , HIV infection). While the prodrugs and nanoparticles as described herein are generally described as ARVs, the prodrugs and nanoformulations as described herein are also effective against other microbial or viral infections including, without limitation: retroviruses, lentiviruses, hepatitis viruses (e. , hepatitis B virus (HBV), hepatitis C virus (HCV) (<NPL>)), herpesviruses (e. , herpes simplex virus (HSV), HSV-<NUM>, HSV-<NUM> (Yan et al. (<NUM>) <NUM>(<NUM>):e01318-<NUM>), and Ebola virus. The prodrugs and nanoformulations as described herein are also effective against other microbial infections such as Mycobacterium tuberculosis or for the treatment of a retrovirus (e. , HIV) in a subject co-infected with Mycobacterium tuberculosis.

In accordance with the instant invention, integrase inhibitor prodrugs are provided, wherein the integrase inhibitor has been modified to be more hydrophobic. The integrase inhibitor prodrugs of the instant invention, particularly the nanoformulations thereof, have improved extended drug half-life, increased hydrophobicity, improved protein binding capacity, increased antiviral efficacy, biodistribution, and plasma half-life compared to native drug. Described herein are integrase inhibitor prodrugs comprising the integrase inhibitor conjugated to a hydrophobic moiety through a hydrolyzable bond, particularly as ester bond. Described herein, the integrase inhibitor is conjugated, optionally via a linker, (e. , at an -OH group; e. , via an acylation reaction) with an aliphatic group or an alkyl (e. , the R group in structures herein). Also described herein, the alkyl or aliphatic group is hydrophobic. Also described herein, the aliphatic group or alkyl comprises about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, or about <NUM> carbons (e. , in the main chain of the alkyl or aliphatic group). Also described herein, the aliphatic group is a C4-C24 unsaturated or saturated aliphatic carbon chain. The aliphatic chain may be substituted with at least one (e. , about <NUM> to about <NUM> or about <NUM> to about <NUM>) heteroatoms (e. , <NUM>, N, or S). Described herein, the aliphatic chain is a fatty acid (saturated or unsaturated) residue. Described herein, the fatty acid is unsaturated. Examples of fatty acids include, without limitation: caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. Described herein, the fatty acid is myristic acid.

Described herein are prodrugs represented as compound of the formula I-A
<CHM>.

Described herein, the DTG prodrug has the following formula:
<CHM>
wherein R is an aliphatic group or an alkyl. In a particular embodiment, the alkyl or aliphatic group is hydrophobic. In a particular embodiment, the aliphatic group or alkyl comprises about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons or about <NUM> carbons (e. , in the main chain of the alkyl or aliphatic group). Described herein, Risa C4-C24 unsaturated or saturated aliphatic chain. The aliphatic may be substituted with at least one (e. , about <NUM> to about <NUM> or about <NUM> to about <NUM>) heteroatoms (e. , <NUM>, N, or S). Described herein, R is the residue (that portion of the fatty acid not including the ester end-group) alkyl chain of a fatty acid (saturated or unsaturated). Described herein, the fatty acid is unsaturated. Examples of fatty acids include, without limitation: caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. Described herein, the fatty acid is myristic acid.

Described herein, the CAB prodrug has the following formula:
<CHM>
wherein R is an aliphatic group or an alkyl. In a particular embodiment, the alkyl or aliphatic group is hydrophobic. In a particular embodiment, the aliphatic group or alkyl comprises about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons or about <NUM> carbons (e. , in the main chain ofthe alkyl or aliphatic group). Described herein, R is a C4-C24 unsaturated or saturated aliphatic chain. The aliphatic may be substituted with at least one (e. , about <NUM> to about <NUM> or about <NUM> to about <NUM>) heteroatoms (e. , <NUM>, N, or S).

Described herein, R is the residue (that portion of the fatty acid not including the ester end-group) alkyl chain of a fatty acid (saturated or unsaturated). Described herein, the fatty acid is unsaturated. Examples of fatty acids include, without limitation: caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. Described herein, the fatty acid is myristic acid.

Described herein, the BIC prodrug has the following formula:
<CHM>
wherein R is an aliphatic group or an alkyl. Described herein, the alkyl or aliphatic group is hydrophobic. Described herein, the aliphatic group or alkyl comprises about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons, about <NUM> to about <NUM> carbons or about <NUM> carbons (e.g., in the main chain of the alkyl or aliphatic group). Described herein, R is a C4-C24 unsaturated or saturated aliphatic chain. The aliphatic may be substituted with at least one (e.g., about <NUM> to about <NUM> or about <NUM> to about <NUM>) heteroatoms (e. g, O, N, or S). Described herein, Risthe residue (that portion of the fatty acid not including the ester end-group) alkyl chain of a fatty acid (saturated or unsaturated). Described herein, the fatty acid is unsaturated. Examples of fatty acids include, without limitation: caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. Described herein, the fatty acid is myristic acid.

Methods of synthesizing hydrophobic integrase inhibitor prodrugs are described herein. Described herein, the integrase inhibitor prodrugs are synthesized through the conjugation of a hydrophobic group such as an aliphatic or alkyl group (e. , a fatty acid) to the integrase inhibitor, optionally via a linker (e. , a carbonyl group). Described herein, the hydrophobic group is conjugated to the integrase inhibitor via an -OH group (e. , via an acylation reaction). Described herein, the hydrophobic group is conjugated through direct conjugation with a fatty acid under acidic conditions or through a group protection and deprotection method. Provided below is a scheme illustrating a method for synthesizing an integrase inhibitor prodrug (DTG (Scheme <NUM>) and CAB (Scheme <NUM>) prodrugs are exemplified, but similar methods can be employed for other integrase inhibitors) as described herein. The reagents, solvents and reaction conditions are illustrative. <CHM>
<CHM>
<CHM>.

Described herein, integrase inhibitor prodrugs can be prepared according to the following steps: <NUM>) deprotonation of the phenol functional group with a base (e. , N,N diisopropylethylamine) and <NUM>) reaction with acyl halide (e. , chloride) or activated carboxylic acid (e. , of a fatty acid), Steps <NUM> and <NUM> reactions may be performed in a single vessel. Also described herein, the hydroxyl group may be deprotonated using the appropriate reagent (e. , a base such as N,N diisopropylethylamine) and the alcohol anion may then be coupled with an acyl chloride or activated carboxylic acid to generate the prodrugs. Coupling reagents used to activate the carboxylic acid include, without limitation uranium salts, carbodiimide reagents, phosphonium salts and the like. The base may include, without limitation: triethylamine, N, N-diisopropylethylamine, collidine, etc. Polar aprotic solvents (e. , without limitation, N,N-dimethylformamide, tetrahydrofuran and acetonitrile) may be used in the coupling reaction. The reagents may be mixed at about <NUM> and gradually warmed to temperature (e.g. , room temperature) (e.g. , over about <NUM>-<NUM> hours), The final compounds may be purified on a silica column chromatography and characterized by nuclear magnetic resonance spectroscopy and high performance liquid chromatography in tandem with mass spectrometry.

The methods for synthesizing the integrase inhibitor prodrugs may further comprise protection of other functional groups (e. , amine and hydroxyl groups) to control chemoselectivity of the reaction. The method may further comprise deprotection after reacting the hydrophobic group with the integrase inhibitor to generate the desired compound. Hydroxyl-protecting groups include, without limitation, esters, acetyls, and ethers such as base sensitive groups like t-butyldimethylsilylchloride (TBDMS-Cl) and t-butyldiphenylsilylchloride. Other hydroxyl-protecting groups include, without limitation, phenylmethyl ether, trimethylsilyl ether, methoxymethyl ether, tetrahydropyranyl ether, t-butyl ether, allyl ether, benzyl ether, acetic acid ester, pivalic acid ester, and benzoic acid ester. The base used in this step may include amines such as, without limitation: pyridine, triethylamine, <NUM>-dimethylaminopyridine, etc. Polar aprotic solvents such as N, N-dimethyl formamide and tetrahydrofuran may be used to run the reaction. The reagents can be mixed at <NUM> and gradually warmed to temperature over time (e. , <NUM>-<NUM> hours). The hydroxyl-protected compounds can be purified by conventional methods such as column chromatography.

Described herein are nanoparticles (sometimes referred to herein as nanoformulations) for the delivery of compounds to a cell. Described herein, the nanoparticle is for the delivery of antiretroviral therapy to a subject. The nanoparticles described herein comprise at least one integrase inhibitor prodrug and at least one surfactant. Also described herein, the nanoparticles comprise a spectroscopic-defined drug: surfactant (polymer) ratio that maintains optimal targeting of the drug nanoparticle to maintain a macrophage depot. Also described herein, the drug: surfactant ratio (by weight) is from about <NUM>:<NUM> to about <NUM>:<NUM>, about <NUM>:<NUM> to about <NUM>:<NUM>, about <NUM>:<NUM> to about <NUM>:<NUM>, or about <NUM>:<NUM>. These components of the nanoparticle, along with other optional components, are described hereinbelow.

Methods of synthesizing the nanoparticles as described herein are known in the art. Described herein, the methods generate nanoparticles comprising the prodrug (e. , crystalline or amorphous) coated (either partially or completely) with a surfactant. Examples of synthesis methods include, without limitation, milling (e. , wet milling), homogenization (e. , high pressure homogenization), particle replication in nonwetting template (PRINT) technology, and/or sonication techniques. For example, <CIT>, incorporated by reference herein, provides methods suitable for synthesizing nanoparticles as described herein. Described herein, the surfactants are firstly chemically modified with targeting ligands and then used directly or mixed with non-targeted surfactants in certain molar ratios to coat on the surface of drug suspensions - e. , by using a nanoparticle synthesis process (e. , a crystalline nanoparticle synthesis process) such as milling (e. , wet milling), homogenization (e. , high pressure homogenization), particle replication in nonwetting template (PRINT) technology, and/or sonication techniques, thereby preparing targeted nanoformulations. The nanoparticles may be used with or without further purification, although the avoidance of further purification is desirable for quicker production of the nanoparticles. Described herein, the nanoparticles are synthesized using milling and/or homogenization. Targeted nanoparticles (e. , using ligands with high molecular weight) may be developed through either physically or chemically coating and/or binding on the surface of surfactants and/or drug nanosuspensions.

The nanoparticles as described herein may be used to deliver at least one prodrug as described herein to a cell or a subject (including non-human animals). Described herein, the nanoparticles as described herein comprise at least two therapeutic agents, particularly wherein at least one is a prodrug as described herein. For example, the nanoparticle may comprise an integrase inhibitor prodrug as described herein and at least one other therapeutic agent (e. , an anti-HIV agent). The nanoparticle may comprise a DTG prodrug of the instant invention and at least one other therapeutic agent (e. , an anti-HIV agent). The nanoparticle may comprise a CAB prodrug as described herein and at least one other therapeutic agent (e. , an anti-HIV agent). The nanoparticle may comprise a BIC prodrug as described herein and at least one other therapeutic agent (e. , an anti-HIV agent). The nanoparticle may comprise a CAB prodrug as described herein, aDTG produg of the instant invention, and, optionally, at least one other therapeutic agent (e. , an anti-HIV agent).

Described herein, the nanoparticles are a submicron colloidal dispersion of nanosized drug crystals (e. , of prodrug) stabilized by surfactants (e. , surfactant-coated drug crystals; a nanoformulation). Described herein, the nanoparticles (or the therapeutic agent (e. , prodrug) of the nanoparticles) may be crystalline (solids having the characteristics of crystals), amorphous, or are solid-state nanoparticles of the therapeutic agent (e. , prodrug) that is formed as crystal that combines the therapeutic agent (e. , prodrug) and surfactant. As used herein, the term "crystalline" refers to an ordered state (i.e., non-amorphous) and/or a substance exhibiting long-range order in three dimensions. Described herein, the majority (e. , at least <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or more) of the therapeutic agent (and, optionally the hydrophobic portion of the surfactant) are crystalline.

Described herein, the nanoparticles are synthesized by adding the therapeutic agent (e. , prodrug, optionally in free base form) to a surfactant (described below) solution and then generating the nanoparticles (e. , by wet milling or high pressure homogenization). The prodrug and surfactant solution may be agitated prior the wet milling or high pressure homogenization.

Described herein, the resultant nanoparticle is up to about <NUM> or <NUM>µmin diameter (e. , z-average diameter) or its longest dimension, particularly up to about <NUM> (e. , about <NUM> to about <NUM>). For example, the diameter or longest dimension of the nanoparticle may be about <NUM> to about <NUM>. Described herein, the diameter or longest dimension of the nanoparticle is about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. The nanoparticles may be, for example, rod shaped, elongated rods, irregular, or round shaped. The nanoparticles as described herein may be neutral or charged. The nanoparticles may be charged positively or negatively.

An anti-HIV compound or an anti-HIV agent is a compound which inhibits HIV. The anti-HIV compound may be in produg form. Examples of additional anti-HIV agents that may be used in combination with the prodrugs of the invention include, without limitation:.

Anti-HIV compounds also include maturation inhibitors (e. , bevirimat). Maturation inhibitors are typically compounds which bind HIV gag and disrupt its processing during the maturation of the virus. Anti-HIV compounds also include HIV vaccines such as, without limitation, ALVAC® HIV (vCP1521), AIDSV AX®B/E (gp120), and combinations thereof. Anti-HIV compounds also include HIV antibodies (e. , antibodies against gp120 or gp41), particularly broadly neutralizing antibodies.

More than one anti-HIV agent may be used, particularly where the agents have different mechanisms of action (as outlined above). For example, anti-HIV agents which are not integrase inhibitors may be combined with the integrase inhibitor prodrugs as described herein. The other anti-HIV agents may be administered concurrently and/or separately with the integrase inhibitor prodrugs as described herein. As explained above, the other anti-HIV agents may be formulated with the integrase inhibitor prodrugs in the nanoparticles as described herein. The other anti-HIV agents may be contained within a composition (e. , a pharmaceutical composition comprising at least one pharmaceutically acceptable carrier) with the integrase inhibitor prodrugs of the instant invention. The other anti-HIV agents may be administered separately (e. , in a composition (e. , a pharmaceutical composition comprising at least one pharmaceutically acceptable carrier)) from the integrase inhibitor prodrugs of the instant invention.

Specific combinations with the integrase inhibitor prodrugs of the instant invention include, without limitation: integrase inhibitor prodrug with rilpivirine, integrase inhibitor prodrug with lamivudine, integrase inhibitor prodrug with lamivudine prodrug (e.g. the lamivudine prodrug described in <CIT>), integrase inhibitor prodrug with lamivudine and abacavir, integrase inhibitor prodrug with lamivudine and abacavir prodrug (e.g., the abacavir prodrug described in <CIT>), integrase inhibitor prodrug with lamivudine prodrug (e.g., the lamivudine prodrug described in <CIT>) and abacavir, integrase inhibitor prodrug with lamivudine prodrug (e.g., the lamivudine prodrug described in <CIT>) and abacavir prodrug (e g. , the abacavir prodrug described in <CIT>), DTG prodrug with rilpivirine, DTG prodrug with lamivudine, DTG prodrug with lamivudine prodrug (e.g. the lamivudine prodrug described in <CIT>), DTG prodrug with lamivudine and abacavir, DTG prodrug with lamivudine and abacavir prodrug (e.g., the abacavir prodrug described in <CIT>), DTG prodrug with lamivudine prodrug (e. , the lamivudine prodrug described in <CIT>) and abacavir, DTG prodrug with lamivudine prodrug (e. , the lamivudine prodrug described in <CIT>) and abacavir prodrug (e. , the abacavir prodrug described in <CIT>), CAB prodrug with rilpivirine, CAB prodrug with lamivudine, CAB prodrug with laminvudine prodrug (e. , the lamivudine prodrug described in <CIT>), CAB prodrug with lamivudine and abacavir, CAB prodrug with lamivudine and abacavirprodrug (e. , the abacavir prodrug described in <CIT>), CAB prodrug with lamivudine prodrug (e. , the laminvudine prodrug described in <CIT>) and abacavir, and CAB prodrug with laminvudine prodrug (e. , the lamivudine prodrug described in <CIT>) and abacavir prodrug (e. , the abacavir prodrug described in <CIT>). As explained above, the other anti-HIV agents may be administered concurrently and/or separately with the integrase inhibitor prodrugs of the instant invention. The other anti-HIV agents may be formulated with the integrase inhibitor prodrugs in the nanoparticles as described herein. The other anti-HIV agents may be contained within a composition (e. , a pharmaceutical composition comprising at least one pharmaceutically acceptable carrier) with the integrase inhibitor prodrugs of the instant invention. The other anti-HIV agents may be administered separately (e. , in a composition (e. , a pharmaceutical composition comprising at least one pharmaceutically acceptable carrier)) from the integrase inhibitor prodrugs of the instant invention.

Described herein, the anti-HIV therapy is highly active antiretroviral therapy (HAART). Described herein, at least two NRTIs and one NNRTI are administered along with the integrase inhibitor prodrugs of the instant invention, optionally with at least one protease inhibitor and/or other anti-HIV agent.

As stated hereinabove, the nanoparticles as described herein comprise at least one surfactant. A "surfactant" refers to a surface-active agent, including substances commonly referred to as wetting agents, detergents, dispersing agents, or emulsifying agents. Surfactants are usually organic compounds that are amphiphilic.

Examples of surfactants include, without limitation, synthetic or natural phospholipids, PEGylated lipids (e. , PEGylated phospholipid), lipid derivatives, polysorbates, amphiphilic copolymers, amphiphilic block copolyemers, poly(ethylene glycol)-co-poly(lactide-co-glycolide) (PEG-PLGA), their derivatives, ligand-conjugated derivatives and combinations thereof. Other surfactants and their combinations that can form stable nanosuspensions and/or can chemically/physically bind to the targeting ligands of HIV infectable/infected CD4+ T cells, macrophages and dendritic cells can be used. Further examples of surfactants include, without limitation:
<NUM>) nonionic surfactants (e. , pegylated and/or polysaccharide-conjugated polyesters and other hydrophobic polymeric blocks such as poly(lactide-co-glycolide) (PLGA), polylactic acid (PLA), polycaprolactone (PCL), other polyesters, poly(propylene oxide), poly(<NUM>,<NUM>-butylene oxide), poly(n-butylene oxide), poly(tetrahydrofurane), and poly(styrene); glyceryl esters, polyoxyethylene fatty alcohol ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, sorbitan esters, glycerol monostearate, polyethylene glycols, polypropyleneglycols, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, aryl alkyl polyether alcohols, polyoxyethylene-polyoxypropylene copolymers, poloxamines, cellulose, methylcellulose, hydroxylmethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, polysaccharides, starch and their derivatives, hydroxyethylstarch, polyvinyl alcohol (PVA), polyvinylpyrrolidone, and their combination thereof); and <NUM>) ionic surfactants (e.g., phospholipids, amphiphilic lipids, <NUM>,<NUM>-dialkylglycero-<NUM>-alkylphophocholines, <NUM>, <NUM>-distearoyl-sn-glecro-<NUM>-phosphocholine (DSPC), <NUM>,<NUM>-distearoyl-sn-glycero-<NUM>-phosphoethanolamine-N-[carboxy(polyethylene glycol) (DSPE-PEG), dimethylaminoethanecarbamoyl cheolesterol (DC-Chol), N-[<NUM>-(<NUM>,<NUM>- Dioleoyloxy)propyl]-N,N,N-trimethylammonium (DOTAP), alkyl pyridinium halides, quaternary ammonium compounds, lauryldimethylbenzylammonium, acyl carnitine hydrochlorides, dimethyldioctadecylammonium (DDAB), n-octylamines, oleylamines, benzalkonium, cetyltrimethylammonium, chitosan, chitosan salts, poly(ethylenimine) (PEI), poly(N-isopropyl acrylamide (PNIPAM), and poly(allylamine) (PAH), poly (dimethyldiallylammonium chloride) (PDDA), alkyl sulfonates, alkyl phosphates, alkyl phosphonates, potassium laurate, triethanolamine stearate, sodium lauryl sulfate, sodium dodecylsulfate, alkyl polyoxyethylene sulfates, alginic acid, alginic acid salts, hyaluronic acid, hyaluronic acid salts, gelatins, dioctyl sodium sulfosuccinate, sodium carboxymethylcellulose, cellulose sulfate, dextran sulfate and carboxymethylcellulose, chondroitin sulfate, heparin, synthetic poly(acrylic acid) (PAA), poly (methacrylic acid) (PMA), poly(vinyl sulfate) (PVS), poly(styrene sulfonate) (PSS), bile acids and their salts, cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid, glycodeoxycholic acid, derivatives thereof, and combinations thereof).

Described herein, the surfactant is present in the nanoparticle and/or surfactant solution to synthesize the nanoparticle (as described hereinabove) at a concentration ranging from about <NUM>% to about <NUM>% or <NUM>% by
weight. Described herein, the concentration of the surfactant ranges from about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, or about <NUM>% to about <NUM>% by weight. Described herein, the nanoparticle comprises at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or higher therapeutic agent by weight.

The surfactant as described herein may be charged or neutral. Described herein , the surfactant is neutral or negatively charged (e. , poloxamers, polysorbates, phospholipids, and their derivatives).

Described herein, the surfactant is an amphiphilic block copolymer or lipid derivative. Described herein, at least one surfactant of the nanoparticle is an amphiphilic block copolymer, particularly a copolymer comprising at least one block of poly(oxyethylene) and at least one block of poly(oxypropylene). Described herein, the surfactant is a triblock amphiphilic block copolymer. Described herein, the surfactant is a triblock amphiphilic block copolymer comprising a central hydrophobic block of polypropylene glycol flanked by two hydrophilic blocks of polyethylene glycol. Described herein, the surfactant is poloxamer <NUM>.

Described herein, the amphiphilic block copolymer is a copolymer comprising at least one block of poly(oxyethylene) and at least one block of poly(oxypropylene). Amphiphilic block copolymers are exemplified, without limitation, by the block copolymers having the formulas:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
In which x, y, z, i, and j have values from about <NUM> to about <NUM>, particularly from about <NUM> to about <NUM> or about <NUM> to about <NUM>, and wherein for each R<NUM>, R<NUM> pair, as shown in formula (IV) and (V), one is hydrogen and the other is a methyl group. The ordinarily skilled artisan will recognize that the values of x, y, and z will usually represent a statistical average and that the values of x and z are often, though not necessarily, the same. Formulas (I) through (III) are oversimplified in that, in practice, the orientation of the isopropylene radicals within the B block will be random. This random orientation is indicated in formulas (IV) and (V), which are more complete. Such poly(oxyethylene)- poly(oxypropylene) compounds have been described by <NPL>); Schmolka (Loc. (<NUM>) <NUM>(<NUM>):<NUM>-<NUM>), <NPL>). A number of such compounds are commercially available under such generic trade names as "lipoloxamers", "Pluronics®,"poloxamers," and "synperonics. " Pluronic® copolymers within the B-A-B formula, as opposed to the A-B-A formula typical of Pluronics®, are often referred to as "reversed" Pluronics®, "Pluronic® R" or "meroxapol. " Generally, block copolymers can be described in terms of having hydrophilic "A" and hydrophobic "B" block segments. Thus, for example, a copolymer of the formula A-B-A is a triblock copolymer consisting of a hydrophilic block connected to a hydrophobic block connected to another hydrophilic block. The "polyoxamine" polymer of formula (IV) is available from BASF under the tradename Tetronic®. The order of the polyoxyethylene and polyoxypropylene blocks represented in formula (IV) can be reversed, creating Tetronic R®, also available from BASF (see, <NPL>). Polyoxypropylene-polyoxyethylene block copolymers can also be designed with hydrophilic blocks comprising a random mix of ethylene oxide and propylene oxide repeating units. To maintain the hydrophilic character of the block, ethylene oxide can predominate. Similarly, the hydrophobic block can be a mixture of ethylene oxide and propylene oxide repeating units. Such block copolymers are available from BASF under the tradename Pluradot™. Poly(oxyethylene)-poly(oxypropylene) block units making up the first segment need not consist solely of ethylene oxide. Nor is it necessary that all of the B-type segment consist solely of propylene oxide units. Instead, in the simplest cases,
for example, at least one of the monomers in segment A may be substituted with a side chain group. A number of poloxamer copolymers are designed to meet the following formula:
<CHM>
Examples of poloxamers include, without limitation, Pluronic® L31, L35, F38, L42, L43, L44, L61, L62, L63, L64, P65, F68, L72, P75, F77, L81, P84, P85, F87, F88, L92, F98, L101, P103, P104, P105, F108, L121, L122, L123, F127, 10R5, 10R8, 12R3, 17R1, 17R2, 17R4, 17R8, 22R4, 25R1, 25R2, 25R4, 25R5, 25R8, 31R1, 31R2, and 31R4. Pluronic® block copolymers are designated by a letter prefix followed by a two or a three digit number. The letter prefixes (L, P, or F) refer to the physical form of each polymer, (liquid, paste, or flakeable solid). The numeric code defines the structural parameters of the block copolymer. The last digit of this code approximates the weight content of EO block in tens of weight percent (for example, <NUM>% weight if the digit is <NUM>, or <NUM>% weight if the digit is <NUM>). The remaining first one or two digits encode the molecular mass of the central PO block. To decipher the code, one should multiply the corresponding number by <NUM> to obtain the approximate molecular mass in daltons (Da). Therefore Pluronic® nomenclature provides a convenient approach to estimate the characteristics of the block copolymer in the absence of reference literature. For example, the code 'F127' defines the block copolymer, which is a solid, has a PO block of <NUM> Da (12X300) and <NUM>% weight of EO. The precise molecular characteristics of each Pluronic® block copolymer can be obtained from the manufacturer.

Other biocompatible amphiphilic copolymers include those described in <NPL>. Examples of other polymers include, without limitation, poly(<NUM>-oxazoline) amphiphilic block copolymers, polyethylene glycol- polylactic acid (PEG-PLA), PEG-PLA-PEG, polyethylene glycol-poly(lactide-co-glycolide) (PEG-PLG), polyethylene glycol-poly(lactic-co-glycolic acid) (PEG-PLGA), polyethylene glycol- polycaprolactone (PEG-PCL), polyethylene glycol-polyaspartate (PEG-PAsp), polyethylene glycol-poly(glutamic acid) (PEG-PGlu), polyethylene glycol- poly(acrylic acid) (PEG-PAA), polyethylene glycol-poly(methacrylic acid) (PEG-PMA),
polyethylene glycol-poly( ethyleneimine) (PEG-PEI), polyethylene glycol-poly(L-lysine) (PEG-PLys), polyethylene glycol-poly(<NUM>-(N,N-dimethy lamino)ethyl methacrylate) (PEG- PDMAEMA), polyethylene glycol-chitosan, and derivatives thereof.

Described herein, the surfactant is poloxamer <NUM> (Pluronic® F127). The
surfactant as described herein may be linked to a targeting ligand. A targeting ligand is a compound that specifically binds to a specific type of tissue or cell type (e. , in a desired target:cell ratio). For example, a targeting ligand may be used for engagement or binding of a target cell (e. , a macrophage) surface marker or receptor which may facilitate its uptake into the cell (e. , within a protected subcellular organelle that is free from metabolic degradation). Described herein, the targeting ligand is a ligand for a cell surface marker/receptor. The targeting ligand may be an antibody or fragment thereof immunologically specific for a cell surface marker (e. , protein or carbohydrate) preferentially or exclusively expressed on the targeted tissue or cell type. Targeting ligands (e. , folic acid) may be conjugated to the polymer by methods known in the art (e. , PCT/USIS/<NUM>). The targeting ligand may be linked directly to the surfactant or via a linker. Generally, the linker is a chemical moiety comprising a covalent bond or a chain of atoms that covalently attaches the ligand to the surfactant. The linker can be linked to any synthetically feasible position of the ligand and the surfactant. Exemplary linkers may comprise at least one optionally substituted; saturated or unsaturated; linear, branched or cyclic aliphatic group, an alkyl group, or an optionally substituted aryl group. The linker may be a lower alkyl or aliphatic. The linker may also be a polypeptide (e. , from about <NUM> to about <NUM> amino acids, particularly about <NUM> to about <NUM>). Described herein, the targeting moiety is linked to either of both ends of the surfactant. The linker may be non-degradable and may be a covalent bond or any other chemical structure which cannot be substantially cleaved or cleaved at all under physiological environments or conditions.

The nanoparticles/nanoformulations as described herein may comprise targeted and/or non-targeted surfactants. As described herein, the molar ratio of targeted and non-targeted surfactants in the nanoparticles/nanoformulations as described herein is from about <NUM> to <NUM>%, about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, about <NUM>% to about <NUM>%, or about <NUM>%. As described herein, the nanoparticle comprises only targeted surfactants. As described herein, the nanoparticles/ nanoformulations of the instant invention comprise a folate targeted surfactant and a non-targeted version of the surfactant. As described herein, the nanoparticles/ nanoformulations as described herein comprise folate-poloxamer <NUM> (FA-P407) and/or poloxamer <NUM>.

The targeted nanoformulations as described herein may comprise a targeting ligand for directing the nanoparticles to HIV tissue and cellular sanctuaries/reservoirs.

Described herein are pharmaceutical compositions comprising at least one prodrug and/or nanoparticle as described herein (sometimes referred to herein as nanoART) and at least one pharmaceutically acceptable carrier. As stated hereinabove, the prodrugs and/or nanoparticles may comprise more than one therapeutic agent. As described herein, the pharmaceutical composition comprises a first prodrugs and/or nanoparticles comprising a first therapeutic agent(s) and a second
nanoparticle comprising a second therapeutic agent(s), wherein the first and second therapeutic agents are different. The pharmaceutical compositions as described herein may further comprise other therapeutic agents (e. , other anti-HIV compounds (e. , those described herein)).

The present invention also encompasses methods for preventing or treating a HIV infection (e. , HIV-<NUM>). The pharmaceutical compositions as described herein can be administered to an animal, in particular a mammal, more particularly a human, in order to.

The dosage ranges for the administration of the pharmaceutical compositions as described herein are those large enough to produce the desired effect (e. , curing, relieving, treating, and/or preventing the HIV infection, the symptoms of it (e. , AIDS, ARC), or the predisposition towards it). Described herein the pharmaceutical composition as described herein is administered to the subject at an amount from about <NUM>µg/kg to about <NUM>/kg. Described herein the pharmaceutical composition as described herein is administered to the subject at an amount greater than about <NUM>µg/kg, greater than about <NUM>µg/kg, greater than about <NUM>/kg, greater than about <NUM>/kg, greater than about <NUM>/kg, or greater than about <NUM>/kg. Described herein, the pharmaceutical composition as described herein is administered to the subject at an amount from about <NUM>/kg to about <NUM>/kg, about <NUM>/kg to about <NUM>/kg, or about <NUM>/kg to about <NUM>/kg. The dosage should not be so large as to cause significant adverse side effects, such as unwanted cross- reactions, anaphylactic reactions, and the like. Generally, the dosage will vary with the age, condition, sex and extent of the disease in the patient and can be determined by one of skill in the art. The dosage can be adjusted by the individual physician in the event of any counter indications.

The prodrugs and/or nanoparticles described herein will generally be administered to a patient as a pharmaceutical composition. The term "patient" as used herein refers to
human or animal subjects. These nanoparticles may be employed therapeutically, under the guidance of a physician.

The pharmaceutical compositions comprising the prodrugs and/or nanoparticles of as described herein may be conveniently formulated for administration with any.

The dose and dosage regimen of prodrugs and/or nanoparticles as described herein that are suitable for administration to a particular patient may be determined by a physician considering the patient's age, sex, weight, general medical condition, and the specific condition for which the prodrugs and/or nanoparticles are being administered and the severity thereof. The physician may also take into account the route of administration,
the pharmaceutical carrier, and the prodrugs and/or nanoparticles's biological activity.

Selection of a suitable pharmaceutical composition will also depend upon the mode of administration chosen. For example, the prodrugs and/or nanoparticles as described herein may be administered by direct injection or intravenously. In this instance, a pharmaceutical composition comprises the prodrugs and/or nanoparticles dispersed in a
medium that is compatible with the site of injection.

Prodrugs and/or nanoparticles as described herein may be administered by any method. For example, the prodrugs and/or nanoparticles as described herein can be administered, without limitation parenterally, subcutaneously, orally, topically, pulmonarily, rectally, vaginally, intravenously, intraperitoneally, intrathecally, intracerbrally, epidurally, intramuscularly, intradermally, or intracarotidly. As described herein, the nanoparticles are administered intramuscularly, subcutaneously, or to the bloodstream (e.g., intravenously). Pharmaceutical compositions for injection are known in the art. If injection is selected as a method for administering the nanoparticle, steps must be taken to ensure that sufficient amounts of the molecules or cells reach their target cells.

Dosage forms for parenteral administration include, without limitation, solutions, emulsions, suspensions, dispersions and powders/granules for reconstitution. Dosage forms for topical administration include, without limitation, creams, gels, ointments, salves, patches and transdermal delivery systems.

Pharmaceutical compositions containing a prodrug and/or nanoparticle as described herein as the active ingredient in intimate admixture with a pharmaceutically acceptable carrier can be prepared according to conventional pharmaceutical compounding techniques. The carrier may take a wide variety of forms depending on the form of pharmaceutical composition desired for administration, e. , intravenous, oral, direct
injection, intracranial, and intravitreal.

A pharmaceutical composition as described herein may be formulated in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form, as used herein, refers to a physically discrete unit of the pharmaceutical composition appropriate for the patient undergoing treatment. Each dosage should contain a quantity of active
ingredient calculated to produce the desired effect in association with the selected pharmaceutical carrier. Procedures for determining the appropriate dosage unit are well known to those skilled in the art. As described herein, the nanoformulations as described herein, due to their long-acting therapeutic effect, may be administered once every <NUM> to <NUM> months or even less frequently. For example, the nanoformulations as described herein may be administered once every <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more months.

Dosage units may be proportionately increased or decreased based on the weight of the patient. Appropriate concentrations for alleviation of a particular pathological condition may be determined by dosage concentration curve calculations, as known in the
art.

As described herein, the appropriate dosage unit for the administration of prodrugs and/or nanoparticles may be determined by evaluating the toxicity of the molecules or cells in animal models. Various concentrations of nanoparticles in pharmaceutical composition may be administered to mice, and the minimal and maximal dosages may be determined based on the beneficial results and side effects observed as a result of the treatment. Appropriate dosage unit may also be determined by assessing the efficacy of the prodrug and/or nanoparticle treatment in combination with other standard drugs. The dosage units of nanoparticle may be
determined individually or in combination with each treatment according to the effect detected.

The pharmaceutical composition comprising the prodrugs and/or.

Also described herein are methods of treating a disease/disorder.

Also described herein is delivering the nanoparticle as described herein to a cell in vitro (e. , in culture). The prodrugs and/or nanoparticles may be delivered to the
cell in at least one carrier.

The following definitions are provided to facilitate an understanding of the present invention.

"Pharmaceutically acceptable" indicates approval by a regulatory agency of the Federal or a state government or listed in the U. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans.

A "carrier" refers to, for example, a diluent, adjuvant, preservative (e. , Thimersol, benzyl alcohol), anti-oxidant (e. , ascorbic acid, sodium metabisulfite), solubilizer (e. , polysorbate <NUM>), emulsifier, buffer (e. , Tris HCl, acetate, phosphate), antimicrobial, bulking substance (e. , lactose, mannitol), excipient, auxiliary agent or.

The term "treat" as used herein refers to any type of treatment that imparts a benefit to a patient afflicted with a disease, including improvement in the condition of the
patient (e. , in one or more symptoms), delay in the progression of the condition, etc. In a particular embodiment, the treatment of a retroviral infection results in at least an inhibition/reduction in the number of infected cells and/or detectable viral levels.

As used herein, the term "prevent" refers to the prophylactic treatment of a subject who is at risk of developing a condition (e. , HIV infection) resulting in a decrease in the probability that the subject will develop the condition.

A "therapeutically effective amount" of a compound or a pharmaceutical composition refers to an amount effective to prevent, inhibit, treat, or lessen the symptoms of a particular disorder or disease. The treatment of a microbial infection (e. , HIV infection) herein may refer to curing, relieving, and/or preventing the microbial infection, the symptom(s) of it, or the predisposition towards it.

As used herein, the term "therapeutic agent" refers to a chemical compound or biological molecule including, without limitation, nucleic acids, peptides, proteins, and antibodies that can be used to treat a condition, disease, or disorder or reduce the symptoms of the condition, disease, or disorder.

As used herein, the term "small molecule" refers to a substance or compound that has a relatively low molecular weight (e. , less than <NUM>,<NUM>, less than <NUM>,<NUM>, particularly
less than <NUM> kDa or <NUM> Da). Typically, small molecules are organic, but are not proteins, polypeptides, or nucleic acids, though they may be amino acids or dipeptides.

The term "antimicrobials" as used herein indicates a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, viruses, or protozoans.

As used herein, the term "antiviral" refers to a substance that destroys a virus and/or suppresses replication (reproduction) of the virus. For example, an antiviral may inhibit and or prevent: production of viral particles, maturation of viral particles, viral attachment, viral uptake into cells, viral assembly, viral release/budding, viral integration,
etc..

As used herein, the term "highly active antiretroviral therapy" (HAART) refers to HIV therapy with various combinations of therapeutics such as nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, HIV protease inhibitors, and fusion inhibitors.

As used herein, the term "amphiphilic" means the ability to dissolve in both water and lipids/apolar environments. Typically, an amphiphilic compound comprises a hydrophilic portion and a hydrophobic portion. "Hydrophobic" designates a preference for apolar environments (e. , a hydrophobic substance or moiety is more readily dissolved in or wetted by non-polar solvents, such as hydrocarbons, than by water). "Hydrophobic" compounds are, for the most part, insoluble in water. As used herein, the term "hydrophilic" means the ability to dissolve in water.

As used herein, the term "polymer" denotes molecules formed from the chemical union of two or more repeating units or monomers. The term "block copolymer" most simply refers to conjugates of at least two different polymer segments, wherein each
polymer segment comprises two or more adjacent units of the same kind.

An "antibody" or "antibody molecule" is any immunoglobulin, including antibodies and fragments thereof (e. , scFv), that binds to a specific antigen. As used herein, antibody or antibody molecule contemplates intact immunoglobulin molecules, immunologically active portions of an immunoglobulin molecule, and fusions of
immunologically active portions of an immunoglobulin molecule.

As used herein, the term "immunologically specific" refers to proteins/polypeptides, particularly antibodies, that bind to one or more epitopes of a protein or compound of interest, but which do not substantially recognize and bind other molecules in a sample containing a mixed population of antigenic biological molecules.

As used herein, the term "targeting ligand" refers to any compound which specifically binds to a specific type of tissue or cell type, particularly without substantially binding other types of tissues or cell types. Examples of targeting ligands include, without
limitation: proteins, polypeptides, peptides, antibodies, antibody fragments, hormones, ligands, carbohydrates, steroids, nucleic acid molecules, and polynucleotides.

The term "aliphatic" refers to a non-aromatic hydrocarbon-based moiety. Aliphatic compounds can be acyclic (e. , linear or branched) or cyclic moieties (e. , alkyl and cycloalkyl) and can be saturated or unsaturated (e. , alkyl, alkenyl, and alkynyl). Aliphatic compounds may comprise a mostly carbon main chain (e. , <NUM> to about <NUM> carbons) and comprise heteroatoms and/or substituents (see below). The term "alkyl", alone or in combination with any other term, refers to a straight-chain or branched-chain saturated aliphatic hydrocarbon radical containing the specified number of carbon atoms,.

"Linker" refers to a chemical moiety comprising a covalent bond or a chain of atoms that covalently attach at least two compounds. The linker can be linked to any synthetically feasible position of the compounds, but preferably in such a manner as to avoid blocking the compounds desired activity. Linkers are generally known in the art. In a particular embodiment, the linker may contain from ∘ (i.e., a bond) to about <NUM> atoms,
from ∘ to about <NUM> atoms, or from about <NUM> to about <NUM> atoms. The linker may be biodegradable under physiological environments or conditions (e. , comprise an ester bond).

The term "alkylene" or "alkenyl" refers to a straight or branched chain divalent hydrocarbon radical, preferably having from one to thirty carbon atoms wherein at least one pair of carbon atoms is connected by a double bond. Examples of "alkylene" as used herein include, but are not limited to, methylene, ethylene, propylene, butylene, isobutylene and the like.

The term "aryl" alone or in combination with any other term, refers to a carbocyclic aromatic moiety (such as phenyl or naphthyl) containing the specified number of carbon atoms, preferably from <NUM>-<NUM> carbon atoms. Examples of aryl radicals include, but are not limited to, phenyl, naphthyl, indenyl, azulenyl, fluorenyl, anthracenyl,.

As used herein, the term "cycloalkyl" refers to a saturated monocyclic carbocyclic ring having from <NUM> to <NUM> carbon atoms, unless a different number of atoms is specified.

The following examples provide illustrative methods of practicing the instant invention, and they are not intended to limit the scope of the invention in any way.

Herein, a novel long acting dolutegravir (DTG) prodrug nanoformulation is provided with improved biological activity, extended drug half-life, increased hydrophobicity, improved protein binding capacity, improved biodistribution (tissue
distribution), improved plasma half-life, and increased antiviral efficacy when compared to the parent drug. The developed hydrophobic modified DTG prodrug (MDTG) exhibits improved cellular uptake of up to <NUM>-fold compared to native drug formulations. Similarly, significant enhancements in cellular retention and antiretroviral activities were seen. Of significance, the MDTG nanoformulations demonstrated an up to a <NUM>-fold improvement in pharmacokinetics compared to native drug formulations. The injectable may be administered once/month or longer and maintain consistent drug concentration. As such, the instant prodrugs and formulations thereof will improve compliance, affect drug reservoir targeting and reduce systemic toxicities. The prodrugs are derivatives of DTG
conjugated to hydrophobic cleavable moieties. Here, the hydrophobic parent compound is converted into a more hydrophobic ester derivative. This is achieved through attachment of a fatty acid, alkyl or aryl moiety that can improve drug protein binding and bioavailability. The ester chemical bond linkage is susceptible to enzymatic cleavage. The derivatives possess improved hydrophobicity when compared to the parent drug. The
"more" hydrophobic nature of the crystalline prodrugs improve nanoformulations by making them even more long acting with improved biopharmaceutic features. The MDTG nanoformulations are composed of hydrophobic prodrug particles dispersed in aqueous suspensions of polymeric excipients. The mechanism of drug release involves dissolution of the prodrug from the excipient follows efficient enzymatic cleavage generating the active agent. The benefits of the system include, without limitation, improved drug bioavailability and extended half-life.

Dolutegravir (DTG) (<NUM>, <NUM> mmol, <NUM> equiv. ) was dissolved in anhydrous dimethylformamide (<NUM>) and cooled to <NUM> under argon. N,N diisopropylethylamine (<NUM>, <NUM> mmol, <NUM> equiv. ) was then added dropwise to the precooled solution of the drug. Myristoyl chloride (<NUM>, <NUM> mmol, <NUM> equiv. ) was then added to the deprotonated phenol solution. The mixture was gradually warmed to room temperature under stirring over <NUM> hours, concentrated, and purified by flash chromatography eluting with <NUM> % EtOAc/Hex to give the prodrug in a chemical yield of <NUM>%. The <NUM>H-NMR spectrum of modified DTG prodrug (MDTG) showed the presence of a broad peak at <NUM>-<NUM> ppm and peaks corresponding to the aliphatic protons on the fatty acid moiety.

The coating polymers used were poloxamer <NUM> (P407), <NUM>,<NUM>-Distearoyl-sn-glycero- <NUM>-phosphocholine (DSPC), <NUM>,<NUM>-distearoy l-sn-glycero-<NUM>-phosphoethanolamine-N-[carboxy(polyethyleneglycol)-<NUM> (DSPE-PEG), and polyvinyl alcohol (PVA).

Based on proton NMR spectroscopy data, a drug to surfactant ratio of <NUM>:<NUM> by weight was used to manufacture nanoformulated MDTG and DTG. Briefly, <NUM>-<NUM>% (w/v) MDTG or DTG and <NUM> - <NUM> % (w/v) P407 were mixed in water. The premixed suspensions were formulated by wet milling or homogenizer at <NUM>,<NUM> psi pressure until
desirable size and polydispersity index were achieved.

Nanoformulations were characterized for particle size, polydispersity index (PDI) and zeta potential by dynamic light scattering (<FIG>). This was done using a Malvern Zetasizer, Nano Series Nano-ZS (Malvern Instruments Inc. , Westborough, MA). Nanoparticle morphology was determined by scanning electron microscopy (SEM). Ultra performance liquid chromatography tandem mass-spectrometry (UPLC MS/MS) was used for drug quantitation. As seen in <FIG>, the hydrophobicity of DTG was greatly improved upon derivatization into MDTG prodrug. Further, the improved hydrophobicity of MDTG facilitated production of stable formulations with high drug loading capacity.

Human monocytes were cultured in macrophage colony stimulating factor containing cell culture medium for <NUM>-<NUM> days in order to differentiate into macrophages (<NPL>; <NPL>). The macrophages were incubated with a range of formulations and native drugs. At each time point, adherent MDM were washed three times with <NUM> of PBS, scraped into <NUM> of fresh PBS and pelleted by centrifugation at <NUM> x g for <NUM> minutes. The cell pellet was reconstituted in <NUM>µl of high performance liquid chromatography (HPLC)-grade methanol and probe sonicated followed by centrifugation at <NUM>,<NUM> x g for <NUM> minutes. The supernatant was analyzed for drug content using HPLC (<FIG>). As seen in <FIG>, conversion of DTG into the more hydrophobic MDTG and nanoparticle formation significantly improved intracellular accumulation of
the drug to levels <NUM> fold higher than nanoformulated DTG.

MDM were treated with either <NUM> DTG, MDTG, P407-MDTG or FA-P407- MDTG for <NUM> hours. The cells were washed with PBS to remove excess of free drug and nanoparticles. The MDM were challenged with HIV-lADA at aMOI of0. <NUM> infectious.

Six weeks old balb/c mice were treated with <NUM>/kg of nanoformulated DTG or <NUM>/kg MDTG (equivalent to <NUM>/kg of DTG). Plasma was collected <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> days after administration. Tissues (liver, kidney, brain, spleen, lymph node, gut and muscle) were collected after sacrifice on day <NUM>. Drug levels from plasma and tissues were assayed by UPLC-MS/MS (<FIG>). Thus, a single intramuscular administration of
nanoformulated MDTG into mice led to improved and sustained DTG blood concentrations of up to <NUM>-fold higher than that of nanoformulated DTG. Notably, plasma DTG concentrations for nanoformulated MDTG at a month were still above the EC90 of DTG.

Herein, novel modified cabotegravir prodrugs (MCAB) are provided as well as their encapsulation into suitable excipients and stabilizers such as nanoformulated poloxamer <NUM> (P407-MCAB) or folic acid (FA) labeled nanoformulations (FA-P407- MCAB) for sustained and site specific drug delivery. The prodrugs comprise native drug.

A solution of cabotegravir (CAB) (<NUM>, <NUM> mmol, <NUM> equiv. ) in anhydrous dimethylformamide (<NUM>) was cooled to <NUM> under argon. N,N diisopropylethylamine (<NUM>, <NUM> mmol, <NUM> equiv. ) was then added dropwise to the precooled solution of the drug. Myristoyl chloride (<NUM>, <NUM> mmol, <NUM> equiv. ) was then added to the deprotonated phenol solution. The mixture was gradually warmed to room temperature under stirring over <NUM> hours, concentrated, and purified by flash chromatography eluting with <NUM> % EtOAc/Hex to give the prodrug in a chemical yield of <NUM>%. The <NUM>H-NMR spectrum of modified cabotegravir prodrug (MCAB) showing the presence of a broad peak at <NUM>-<NUM> ppm and peaks corresponding to the aliphatic protons on the fatty acid moiety.

Coating polymers used were poloxamer <NUM> (P407), <NUM>,<NUM>-Distearoyl-sn-glycero-<NUM>- phosphocholine (DSPC), <NUM>,<NUM>-distearoy l-sn-glycero-<NUM>-phosphoethanolamine-N- [carboxy(polyethylene glycol)-<NUM> (DSPE-PEG), polyvinyl alcohol (PVA).

Based on proton NMR spectroscopy data, a drug to surfactant ratio of <NUM>:<NUM> by weight was used to manufacture nanoformulated MCAB and CAB. Briefly, <NUM>-<NUM>% (w/v) MCAB or CAB and <NUM> - <NUM> % (w/v) P407 were mixed in water. The premixed suspensions were formulated by wet milling or homogenizer at <NUM>,<NUM> psi pressure until desirable size and polydispersity index were achieved.

Nanoformulations were characterized for particle size, polydispersity index (PDI) and zeta potential by dynamic light scattering (DLS) (Table <NUM>). This was done using a Malvern Zetasizer, Nano Series Nano-ZS (Malvern Instruments Inc, Westborough, MA). Nanoparticle morphology was determined by scanning electron microscopy (SEM). UPLC
MS/MS was used for drug quantitation. As seen in Table <NUM>, the hydrophobicity of CAB was greatly improved upon derivatization into MCAB. The improved hydrophobicity of MCAB facilitated production of stable formulations with high drug loading capacity.

Human monocytes were cultured in macrophage colony stimulating factor containing cell culture medium for <NUM>-<NUM> days in order to differentiate into macrophages (<NPL>; <NPL>). The macrophages were incubated with a range of formulations and native
drugs. At each time point, adherent monocyte-derived macrophage (MDM) were washed three times with <NUM> of PBS, scraped into <NUM> of fresh PBS and pelleted by centrifugation at <NUM> x g for <NUM> minutes. The cell pellet was reconstituted in <NUM>µl of high performance liquid chromatography (HPLC)-grade methanol and probe sonicated followed by centrifugation at <NUM>,<NUM> x g for <NUM> minutes. The supernatant was analyzed for
drug content using HPLC (<FIG>). The MCAB nanoformulations were easily taken up by human monocyte derived macrophages (MDM) with sustained drug release up to <NUM> days; whereas parent drug formulations were eliminated from MDM within a single day of treatment.

MDM were treated with either <NUM> CAB long acting parenteral (CAB-LAP), P407-CAB, P407-MCAB or FA-P407-MCAB for <NUM> hours. The cells were washed with PBS to remove excess of free drug and nanoparticles. The MDM were challenged with HIV-1ADA at a MOI of <NUM> infectious viral particles/cell for <NUM> hours on day <NUM>,<NUM>,<NUM> and.

As seen in <FIG>, conversion of CAB into more hydrophobic MCAB and nanoparticle formation significantly improved intracellular accumulation of the drug compared to CAB-LAP. Significant improvements in MDM retention and antiretroviral efficacy were also observed for nanoformulated MCAB. Notably, MDM treated with nanoformulated MCAB exhibited enhanced antiretroviral activity compared to nanoformulated parent drug when MDM are infected at days <NUM>, <NUM>, <NUM> and <NUM> after drug treatment. HIV-1p24 was not detected in the NMCAB-treated group at any of these time points.

A number of publications and patent documents are cited throughout the foregoing specification in order to describe the state of the art to which this invention pertains.

Claim 1:
A prodrug compound of the formula I-A
<CHM>
or pharmaceutically acceptable salts thereof
wherein ring A is
<CHM>
the stereochemistry of an asymmetric carbon represented by * shows R- or S- configuration, or a mixture thereof,
m is <NUM>, <NUM>, <NUM>, or <NUM>,
and wherein R is a fatty acid residue, wherein the fatty acid is selected from caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid.