WO2017100597A1

WO2017100597A1 - Particle delivery of prostaglandin receptor agonists and antagonists

Info

Publication number: WO2017100597A1
Application number: PCT/US2016/065861
Authority: WO
Inventors: W. Stephen Faraci; Bernadette C. FENDROCK; Roman HERRERA
Original assignee: Cyta Therapeutics, Inc.
Priority date: 2015-12-11
Filing date: 2016-12-09
Publication date: 2017-06-15

Abstract

The present invention in various aspects and embodiments involves pharmaceutical compositions comprising a prostaglandin receptor agonist or antagonist encapsulated in a pharmaceutically acceptable microparticle or nanoparticle carrier. The invention allows for prostaglandins, including analogues that are prostaglandin receptor agonists or antagonists, to be delivered in a tissue selective and/or controlled manner.

Description

PARTICLE DELIVERY OF PROSTAGLANDIN RECEPTOR AGONISTS AND

ANTAGONISTS

BACKGROUND

The prostaglandins (PG) are a group of physiologically active lipids having diverse hormone-like effects in animals. Prostaglandins are derived enzymatically from fatty acids, and have 20 carbon atoms including a 5-carbon ring. They are a subclass of eicosanoids and form the prostanoid class of fatty acid derivatives.

The structural differences between prostaglandins account for their different biological activities. A given prostaglandin may have different and even opposite effects in different tissues, and may have biological effects that are concentration dependent. The ability of the same prostaglandin to stimulate a reaction in one tissue and inhibit the same reaction in another tissue is determined by the type of receptor to which the prostaglandin binds. They act as autocrine or paracrine factors with their target cells present in the immediate vicinity of the site of their secretion.

For example, prostaglandin E2 (PGE₂) has important effects in labor (softening the cervix and causing uterine contraction) and also stimulates osteoblasts to release factors that stimulate bone resorption by osteoclasts. PGE₂ is also induces fever, suppresses T cell receptor signaling, and may play a role in resolution of inflammation. PGE₂ is implicated in regulating the developmental specification and regeneration of hematopoietic stem cells, and plays a role in stimulating liver regeneration. Ayabe S., et al., Prostaglandin E? induces contraction of liver myofibroblasts by activating EP^ and FP prostanoid receptors, British J. Pharmacol. 156:835-845 (2006); and WO 2008/070310, each of which is hereby incorporated by reference in their entireties. Prostaglandins are synthesized in the cell, and their release is mediated by a transporter. The concentration of prostaglandins outside the cell is further regulated by an enzyme, 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Inhibitors of 15-PGDH have been postulated as an opportunity to potentiate prostaglandin activity. Compositions and methods for administering prostaglandin receptor agonists and antagonists in a tissue or cell selective manner are needed.

BRIEF DESCRIPTION OF THE INVENTION

The present invention in various aspects and embodiments involves pharmaceutical compositions comprising a prostaglandin receptor agonist or antagonist encapsulated in a pharmaceutically acceptable microparticle or nanoparticle carrier. The invention allows for prostaglandins, including analogues that are prostaglandin receptor agonists or antagonists, to be delivered in a tissue selective and/or controlled manner. An exemplary prostaglandin receptor agonist is PGE₂, which finds use in, among other things, tissue regeneration.

Various microparticle and nanoparticle delivery systems are described herein, and include polymeric nanoparticles such as PLGA-PEG particles that can be formulated to provide a sustained release of active agent at the level of a target tissue or cell. In other embodiments, degradation of the nanoparticle or microparticle carrier is triggered or accelerated by an intracellular or endosomal environment (e.g, increased concentration of biochemical reductant or by acidic pH), allowing the active agent to be released intracellularly. In these embodiments, the nanoparticle or microparticle carrier is not substantially degraded in blood or plasma, but is degraded in the intracellular space of cells in target tissues. Target cells subsequently release the active agent to act on local cells. In some embodiments, the pharmaceutical composition targets specific tissues or cells. For example, the pharmaceutical composition may comprise a targeting agent that directs the nanoparticle or microparticle carrier to target tissues or cells by binding to a ligand on the surface of target cells, including but not limited to hepatocytes. In other embodiments, the pharmaceutical composition may be directed by passive targeting, such as by diffusion and accumulation in target tissues.

In other aspects, the invention provides a method for treating diseases and conditions that are treatable by tissue- or cell-selective delivery of prostaglandin receptor agonists or antagonists, such as but not limited to PGE₂. In various embodiments, the patient may be a transplant donor or recipient, or may be suffering from liver failure, kidney failure, inflammatory bowel disease (IBD) or ulcerative colitis (UC), excessive pain or hyperalgesia, irritated stomach, asthma, among others. For example, in some embodiments, the invention provides for delivery of PGE₂ selectively to the liver to stimulate liver regeneration. Other aspects and embodiments of the invention will be apparent from the following detailed description.

DETAILED DESCRIPTION

The present invention provides tissue-selective delivery of prostaglandins using particle delivery systems. The particle delivery systems in some embodiments provide sustained and/or controlled levels of prostaglandins, including derivatives that are receptor agonists or antagonists, in select tissues to induce desired biological effects. Specifically, the invention provides pharmaceutical compositions comprising a prostaglandin receptor agonist or antagonist encapsulated in a pharmaceutically acceptable microparticle or nanoparticle carrier, as well as methods for producing and using the same. The invention allows for the medical potential of various prostaglandin receptor agonists or antagonists to be realized, and in particular those that have medically-important tissue-specific or cell-specific biological effects. Prostaglandins have biological actions on many different cell types and have a wide variety of biological effects such as: constriction or dilation in vascular smooth muscle cells; aggregation or disaggregation of platelets; sensitizing spinal neurons to pain; induction of labor; decreasing of intraocular pressure; regulating inflammation; regulating calcium movement; regulating hormones; controlling cell growth; production of fever; increasing glomerular filtration rate; and inhibiting acid secretion in the stomach. In some embodiments, particles comprise a prostaglandin receptor agonist, such as prostaglandin E2 (PGE₂) or derivative thereof, which finds use in, for example, tissue regeneration, including liver regeneration.

In various embodiments, the encapsulated prostaglandin is one or more of a prostaglandin A (PGA), a prostaglandin B (PGB), a prostaglandin C (PGC); a prostaglandin D (PGD), a prostaglandin E (PGE), a prostaglandin F (PGF), a prostaglandin G (PGG), a prostaglandin H (PGH), and a prostaglandin I (PGI), thromboxane A, including any subtype thereof. For example, the PGE may be PGEi or PGE₂.

The active agent may be an agonist or antagonist at one or more prostaglandin receptors, such as but not limited to: the DPI, DP2 receptors, the EPl, EP2, EP3, and EP4 receptors, the FP receptors, the IPl and IP2 receptors, and the TP receptors. For example, the effects of PGE₂ may be mediated by the EPl, EP2, EP3 and/or EP4 receptors. Prostaglandin receptor agonists include but are not limited to natural prostaglandin structures, as well as derivatives of natural prostaglandins that binds to one or more prostaglandin receptors and affect cell or tissue functions. Prostaglandin receptor antagonist include but are not limited to: any inhibitor of a natural prostaglandin function by reducing or blocking the signaling cascade of a prostaglandin, and any molecule that reduces or blocks the binding of the prostaglandin to the prostaglandin receptor, such as but not limited to a prostaglandin derivative or analog that competitively binds to the prostaglandin receptor and reduces the signaling of the prostaglandin receptor by prostaglandin binding.

In some embodiments, the prostaglandin receptor agonist is a natural prostaglandin, such as but not limited to PGD1, PGE₂, PGI₂ and PGF₂a. In some embodiments, the prostaglandin receptor agonist is PGE₂. In some embodiments, the prostaglandin receptor agonist is a derivative or analog of a natural prostaglandin, such as but not limited to: dimethyl-PGE₂, alprostadil, misoprostol, bimatoprost, latanoprost, tafluprost, travoprost, and unoprostone. In some embodiments, the PGE₂ receptor agonist is a PGE₂ receptor agonist disclosed in U.S. Pat. Nos. 5,703, 108, 6,344,477, 6,437, 146, 6,462,080, 6,462,081, 6,498,172, 6,531,485, 6,545,045, 6,548,544, 6,562,868, 6,610,719, 6,642,266, 6,900,336, 7,271,183, 7,276,531, 7,419,999, 7,442,702, 7,893, 107, and 8,980,944, U.S. Pat. App. Pub. Nos. 2001/0041729, 2002/0044953, 2002/0115695, 2003/0176479, 2004/0142969, 2005/0112075, 2005/0215609, 2007/0232660, 2008/0132543, 2010/135404, 2010/0298436, 2011/0046385, 2012/0283293, 2014/0371147, 2014/0255358, and 2014/0142042, and PCT App. Pub. Nos. WO 1999/019300, WO 1999/002164, WO2004/012656, WO2009/027811, and WO2014/152809, which are all hereby incorporated by reference. In some embodiments, the prostaglandin receptor antagonist reduces natural prostaglandin effects by inhibiting prostaglandin signaling cascade or reducing or blocking the binding of prostaglandin and prostaglandin receptors. In some embodiments, the prostaglandin receptor antagonist is a PGE₂ receptor antagonist capable of reducing or blocking the effects of natural PGE₂. For example, in one embodiment the prostaglandin receptor antagonist is a molecule disclosed in one or more of U.S. Pat. Nos. 4,632,928, 5,747,660, 5,955,575, 4,632,928, 5,747,660, 6,369,089, 6,407,250, 6,509,364, 6,511,999, 5, 100,889, 5, 153,327, 5,605,917, 6,984,719, 7,273,883, 7,642,249, 8,067,445, 8,404,736, and 8,969,589, U.S. Pat. App. Pub. Nos. 2001/0047027, 2002/0052416, 2005/0065200, 2005/0059742, 2004/0162323, 2008/0275095, 2009/0176804, 2009/0239845, 2010/0256385, 2013/0005741, 2014/0179750, and 2015/0099782, and PCT App. Pub. Nos. WO2001079169 and WO2008039882, which are each hereby incorporated by reference.

The pharmaceutical composition comprises a nanoparticle or microparticle carrier to deliver the active agent to desired tissues or cells. As used herein, the term "nanoparticle," refers to a particle having at least one dimension in the range of about 1 nm to about 1000 nm. The term "microparticle" includes particles having at least one dimension in the range of at least about one micrometer (μιη). The term "particle" includes nanoparticles and microparticles. The size of the particle carrier can impact the pharmacodynamics of the composition, including tissue distribution, cell internalization, and size of the payload, for example. In various embodiments, the particle may have a size (e.g., average diameter) in the range of about 25 nm to about 5 μιη. In various embodiments, the particle carrier may have a size in the range of about 25 nm to about 500 nm, or in the range of about 50 nm to about 300 nm, or in the range of about 50 nm to about 250 nm, or in the range of about 50 to 150 nm.

In some embodiments, the nanoparticle or microparticle is polymeric. For example, the particle carrier may comprise a material having one or more degradable linkages, such as an ester linkage, a disulfide linkage, an amide linkage, an anhydride linkage, and a linkage susceptible to enzymatic degradation. For example, the nanoparticle or microparticle may comprise polymers or copolymers selected from cyclodextrin, poly(D,L-lactic acid-co-glycolic acid) (PLGA), poly(caprolactone) (PCL), ethylene vinyl acetate polymer (EVA), poly(lactic acid) (PLA), poly(L-lactic acid) (PLLA), poly(glycolic acid) (PGA), poly(L-lactic acid-co-glycolic acid) (PLLGA), poly(D,L-lactide) (PDLA), poly(L-Lactide) (PLLA), PLGA-b-poly(ethylene glycol)-PLGA (PLGA-bPEG-PLGA), PLLA-bPEG-PLLA, PLGA-PEG, poly(D,L-lactide-co-caprolactone), poly(D,L-Lactide- co-caprolactone-co-glycolide), poly(D,L-lactide-co-PPO-co-D,L-lactide), polyalkyl cyanoacrylate, polyurethane, poly-L-lysine (PLL), hydroxypropyl methacrylate (FIPMA), polyethyleneglycol, poly-L-glutamic acid, poly(hydroxy acids), polyanhydrides, polyorthoesters, poly(ester amides), polyamides, poly(ester ethers), polycarbonates, polyalkylenes, polyalkylene oxides (PEO), polyalkylene terephthalates, polyvinyl alcohols (PVA), polyvinyl ethers, polyvinyl esters such as poly(vinyl acetate), polyvinyl halides such as poly(vinyl chloride) (PVC), polyvinylpyrrolidone, polysiloxanes, polystyrene (PS), derivatized celluloses such as alkyl cellulose, hydroxy alkyl celluloses, cellulose ethers, cellulose esters, nitro celluloses, hydroxypropylcellulose, carboxymethylcellulose, polymers of acrylic acids, such as polymethylmethacrylate) (PMA), poly(ethyl(meth)acrylate), poly(butyl(meth)acrylate), poly (isobutyl (meth)acrylate), poly(hexyl(meth)acrylate), poly(isodecyl(meth)acrylate), poly(lauryl(meth)acrylate), poly(phenyl(meth)acrylate), poly(methyl acrylate), poly(isopropyl acrylate), polyiisobutyl acrylate), poly(octadecyl acrylate) (poly acrylic acids), polydioxanone, polyhydroxyalkanoates, polypropylene fumarate, polyoxymethylene, poloxamers, poly(ortho)esters, poly(butyric acid), poly(valeric acid), poly(lactide-co-caprolactone), trimethylene carbonate, polyvinylpyrrolidone, polyorthoesters, polyphosphazenes, and polyphosphoesters. In one embodiment, the nanoparticle or microparticle may comprise PLGA or PLGA-PEG polymers. In alternative embodiments, the nanoparticle or microparticle may be a micellar assembly comprising surfactants or liposome. Various nanoparticle or microparticle carrier systems have been described, and find use with the invention, including those described in US 8,206,747, US 2014/0112881, US 2015/0202163, US 2015/0209447, and WO/2015/105549, which are hereby incorporated by reference in their entireties. The nanoparticle or microparticle may be designed to provide desired pharmacodynamic advantages, including circulating properties, biodistribution, and degradation kinetics. Such parameters include size, surface charge, polymer composition, targeting ligand conjugation chemistry, among others. For example, in some embodiments, the particles have a PLGA polymer core, and a hydrophilic shell formed by the PEG portion of PLGA-PEG co-polymers. The hydrophilic shell may further comprise ester-endcapped PLGA-PEG polymers that are inert with respect to functional groups, such as PLGA-PEG-MeOH polymers.

The nanoparticles can be tuned for a specific biodegradation rate in vivo by adjusting the LA:GA ratio and/or molecular weight of the PLGA polymer. In some embodiments, the PLGA is based on a LA:GA ratio of from 20: 1 to 1 :20, including compositions of L/G of: 5/95, 10/90, 15/85, 20/80, 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/15, 90/10, or 95/5. PLGA degrades by hydrolysis of its ester linkages. The time required for degradation of PLGA is related to the ratio of monomers: the higher the content of glycolide units, the lower the time required for degradation as compared to predominantly lactide units. In addition, polymers that are end-capped with esters (as opposed to the free carboxylic acid) have longer degradation half-lives. The molecular weights of the PLGA and PEG co-polymers allows for tunable particle size. For example, PLGA co-polymers may have a molecular weight within about 10K to about 100K, and PEG co-polymers may have a molecular weight within about 2K to about 20K.

The prostaglandin receptor agonist or antagonist may be non-covalently incorporated into the particle carrier. For example, the prostaglandin receptor agonist or antagonist may be non-covalently incorporated into a crosslinked or non-crosslinked network of polymer molecules, which are part of the polymeric carrier. In other embodiments, the prostaglandin receptor agonist or antagonist is covalently linked to the nanoparticle or microparticle carrier, and released upon degradation of the carrier.

In some embodiments, the nanoparticle or microparticle carrier is formed by self- assembly in an aqueous environment. For example, the particles may be formed by self- crosslinking reactions with self-crosslinking polymer as described in US 2014/0112881, which is hereby incorporated by reference.

In particular embodiments, the carrier comprises an oligoethylene glycol (OEG) hydrophilic shell and a lipophilic interior comprising disulfide-crosslinked branch groups, allowing the carrier to degrade in the presence of intracellular concentrations of glutathione (GSH). In these embodiments, the particles may be formed from amphiphilic polymers comprising the hydrophilic OEG branch groups and the lipophilic branch groups.

The oligoethylene glycol (OEG) groups include

, wherein p is an integer from about 5 to about 200 (e.g., from about 5 to about 150, from about 5 to about 100, from about 5 to about 50, from about 10 to about 200, from about 20 to about 200, from about 50 to about 200, from about 100 to about 200, from about 10 to about 30, from about 10 to about 50). In some embodiments, the OEG branch groups have from 5 to 50 ethylene glycol units. OEG units may be used to introduce a charge-neutral hydrophilic functional group, which is known to endow biocompatibility. Lipophilic branch groups comprise a lipophilic moiety to drive particle assembly and allow crosslinking of the interior. For example, the lipophilic branch groups may comprise pyridyldisulfide (PDS) moieties. The lipophilic functionality provides a supramolecular amphiphilic nano-assembly in the aqueous phase, which helps avoid the use of any additional surfactant molecules to generate the nanogel. The amphiphilic nature of the nanoparticle or microparticle carrier (e.g. nanogel) and lipophilic environment provides the opportunity for lipophilic guest molecules, such as but not limited to PGE₂, to be sequestered within these nano-assemblies prior to crosslinking. The PDS functionality is reactive, but specific, to thiols and provides a mild method for disulfide crosslinking to form the nanogel. Furthermore, since the nanoparticle or microparticle carriers may be based on disulfide crosslinkers that can be cleaved by thiol-disulfide exchange reactions, these nanogels also have a pathway to release the stably encapsulated guest molecules. Further, because the nanoparticle or microparticle formation can be conducted with thiol- disulfide exchange or thiol reshuffling reactions, the use of organic solvents and metal containing catalysts or additional reagents can be avoided. In some embodiments, the disulfide exchange reaction may shuffle sulfhydryl groups of dithiothreitol (DTT) into the disulfides of disulfide-linked lipophilic branch groups.

The OEG branch groups and the lipophilic branch groups may be present at a ratio of from 1 :4 to 4: 1. In one embodiment, the OEG branch groups and the lipophilic branch groups may be present at a ratio of about 1 :4, 1 : 3, 1 :2, 1 : 1, 2: 1, 3 : 1 or 4: 1.

The amphiphilic co-polymer may be prepared by reversible addition fragmentation chain transfer (RAFT) polymerization of pyridyl disulfide ethyl methacrylate (PDSEMA) and oligoethylene glycol monomethyl ether methacrylate. The resulting polymer may be purified with precipitation methods. See, for example, US 2014/0112881, which is hereby incorporated by reference.

In some embodiments, the crosslinked network of the nanoparticle or microparticle may have a crosslinking density in the range of from 2% to 80%, relative to the total number of structural units in the polymer. For example, the crosslinked network of may have a crosslinking density from about 2%> to about 70%>, from about 2%> to about 60%>, from about 2%> to about 50%>, from about 2%> to about 40%>, from about 2%> to about 30%>, from about 2%> to about 20%>, from about 2%> to about 10%>, from about 5%> to about 80%>, from about 10%> to about 80%>, from about 20%> to about 80%>, from about 30%> to about 80%), from about 40%> to about 80%>, relative to the total number of structural units in the polymer.

Other variations for formulation of particle carriers in accordance with this disclosure may be used, including those described in one or more of US 2014/0112881, US 2015/0202163, US 2015/0209447, and WO/2015/105549, which are hereby incorporated by reference in their entireties. In another aspect, the invention relates to a method for making the pharmaceutical composition described herein. The method comprises incorporating the prostaglandin receptor agonist or antagonist into a nanoparticle or microparticle carrier, including by cross-linking of lipophilic branch groups as described above, or by nanoprecipitation using PLGA-PEG polymers or similar polymer constructs.

The prostaglandin receptor agonist or antagonist, such as but not limited to PGE₂, is released upon partial or complete degradation or de-crosslinking of polymer molecules at or near the biological site. For example, after transport of the nanoparticle or microparticle carrier to the target tissue or cells, the carrier may be degraded or de-crosslinked, thereby releasing the active agent. In one embodiment, the degradation is triggered by an endosomal or intracellular environment upon cell internalization. For example, the degradation may be caused by breaking the disulfide bonds in the nanoparticle or microparticle carrier in a reducing environment. Alternatively, degradation of the nanoparticle or microparticle carrier may be triggered by low pH. In some embodiments, the active agent is not substantially released at concentrations of reducing agent characteristic of blood plasma, so that active agent is only released after cell internalization. In one aspect, the pharmaceutical composition of the current application may comprise a targeting agent to direct the nanoparticle or microparticle carrier to target tissues or cells. Such targeting may improve the efficiency and effectiveness of the guest molecule, such as prostaglandin (e.g. PGE₂), as the local concentration of the guest molecule is elevated. In some embodiments, the targeting agent may be a tissue selective targeting agent, or may be selective for certain cells, such as but not limited to hepatocytes. Nanoparticle or microparticle carriers in these embodiments, which comprise prostaglandin (e.g. PGE₂) may be used in a treatment of diseases and conditions related to prostaglandin functions. The common strategies for targeted drug deliver are described in Muro S., Challenges in design and characterization of ligand-targeted drug delivery systems, J. Control Release, 164(2): 125-37 (2012).

In some embodiments, the targeting agent may be an antibody or antigen-binding fragment thereof. In other embodiments, the targeting agent may a peptide, aptamer, adnectin, polysaccharide, or biological ligand. The various formats for target binding include a single-domain antibody, a recombinant heavy-chain-only antibody (VHH), a single-chain antibody (scFv), a shark heavy-chain-only antibody (VNAR), a microprotein (cysteine knot protein, knottin), a DARPin, a Tetranectin, an Affibody; a Transbody, an Anticalin, an AdNectin, an Affilin, a Microbody, a peptide aptamer, a phylomer, a stradobody, a maxibody, an evibody, a fynomer, an armadillo repeat protein, a Kunitz domain, an avimer, an atrimer, a probody, an immunobody, a triomab, a troybody, a pepbody, a vaccibody, a UniBody, a DuoBody, a Fv, a Fab, a Fab', a F(ab')2, a peptide mimetic molecule, or a synthetic molecule, or as described in US Patent Nos. or Patent Publication Nos. US 7,417,130, US 2004/132094, US 5,831,012, US 2004/023334, US 7,250,297, US 6,818,418, US 2004/209243, US 7,838,629, US 7,186,524, US 6,004,746, US 5,475,096, US 2004/146938, US 2004/157209, US 6,994,982, US 6,794, 144, US 2010/239633, US 7,803,907, US 2010/119446, and/or US 7, 166,697, the contents of which are hereby incorporated by reference in their entireties. See also, Storz MAbs. 2011 May- Jun; 3(3): 310-317. Exemplary targeting agents include antigen-binding antibody fragments, such as but not limited to F(ab')2 or Fab, a single chain antibody, a bi-specific antibody, or a single domain antibody.

In certain embodiment, the targeting agent is triantennary N-Acetylgalactosamine (GalNAc), dimeric GalNAc or monomelic GalNAc, which targets the particle carriers to hepatocytes. Alternative targeting agents may bind integrins (e.g., RGD peptide), and in some embodiments may be a cell-penetrating peptide (CPP). The targeting agent can be chemically conjugated to the particles using any available process. Functional groups for conjugation include COOH, NH₂, and SH. See, e.g., Hermanson, BIOCONJUGATE TECHNIQUES, Academic Press, New York, 1996. Activating functional groups include alkyl and acyl halides, amines, sulfhydryls, aldehydes, unsaturated bonds, hydrazides, isocyanates, isothiocyanates, ketones, and other groups known to activate for chemical bonding. Alternatively, the targeting agent can be conjugated through the use of a small molecule-coupling reagent. Non-limiting examples of coupling reagents include carbodiimides, maleimides, N-hydroxysuccinimide esters, bischloroethylamines, bifunctional aldehydes such as glutaraldehyde, anhydrides and the like. Additional cellular targets and potential target tissues and cells are summarized in Table 1.

Table 1

MUC1 Breast and bladder cells

PEC AM- 1 Immune cells

Selectins Vascular cells (e.g. in solid

tumors) and immune cells

Transferrin receptor Cancer cells and blood-brain- barrier

VCAM-1 Vascular cells (e.g. in solid

tumors) and immune cells

VEGF receptor Vascular cells (e.g. in solid

tumors).

In some embodiments, the targeting agent may be conjugated or attached to the surface of the nanoparticle or microparticle. In one embodiment, the targeting agent is an antibody or antibody fragment linked to the polymeric units on the surface of the nanoparticle or microparticle, either non-covalently or covalently.

In some embodiments, the nanoparticle or microparticle is targeted to the liver, kidney, lung, heart, nerves, macrophages, hematopoietic stem cells, hepatic stellate cells, vasculature, brain, vagina, uterus, stomach, intestine (small and large intestine), or muscles of specific organs. In one embodiment, the guest molecule is a prostaglandin receptor agonist or antagonist, or more specifically a PGE₂, and is targeted to a cell or tissue selected from hepatocytes, vasculature, smooth muscles (e.g. smooth muscles associated with bronchoconstriction or smooth muscles associated with gastrointestinal tract), kidney, immune cells, stomach, uterus (or smooth muscle of the uterus), or neuronal cells such as but not limited to peripheral nerves.

In one aspect, the nanoparticle or microparticle may be directed by passive targeting, referring to the accumulation of the nanoparticle or microparticle into particular regions of the body due to the natural features and physiological role of the tissues and cells. In some embodiments, the nanoparticle or microparticle carrier may accumulate in the desired tissues or cells in the absence of a targeting agent. For example, the nanoparticle or microparticle carrier may accumulate in organs of the reticulo-endothelial system (RES), such as but not limited to the liver and/or the spleen, which may capture foreign substances and objects that reach the systemic circulation. In one embodiment, the nanoparticle or microparticle carrier may accumulate in the monocyte/macrophage system. In another embodiment, the nanoparticle or microparticle carrier may accumulate in the vasculature of tumors, which show an enhanced permeability and retention effect. In some embodiments, the nanoparticle or microparticle carrier is accumulated in liver, kidney, and/or lung.

The pharmaceutical composition may be formulated into liquid or solid dosage forms and administered systemically or locally. The pharmaceutical composition may be delivered, for example, in a timed- or sustained-low release form as is known to those skilled in the art. Techniques for formulation and administration may be found in Remington: The Science and Practice of Pharmacy (20th ed.) Lippincott, Williams & Wilkins (2000). Suitable routes may include oral, buccal, by inhalation spray, sublingual, rectal, transdermal, vaginal, transmucosal, nasal or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intramedullary injections, as well as intrathecal, direct intraventricular, intravenous, intra-articular, intra-sternal, intra-synovial, intra-hepatic, intralesional, intracranial, intraperitoneal, intranasal, or intraocular injections or other modes of delivery.

While the form and/or route of administration can vary, in some embodiments the pharmaceutical composition is administered parenterally (e.g., by subcutaneous, intravenous, or intramuscular administration). For injection, the agents of the disclosure may be formulated and diluted in aqueous solutions, such as in physiologically compatible buffers such as Hank's solution, Ringer's solution, or physiological saline buffer.

In some embodiments employing oral administration or administration to the GI, the pharmaceutical composition may further comprise an enteric coating. The enteric coating controls the release of the nanoparticles to avoid harsh environments of the stomach for example, by employing a coating that is insoluble at low pH, but soluble at higher pH so as to release particle carriers in the small or large intestine. In one aspect, the invention relates to using the pharmaceutical composition described herein to treat diseases and conditions associated with prostaglandin functions, such as but not limited to a regenerative condition.

In some embodiments, the pharmaceutical composition is administered by intravenous or intraarterial administration, oral administration, or direct administration to desired tissues. In some embodiments, the pharmaceutical composition is administered from once daily to about once monthly. In some embodiments, particles are formulated to have a longer half-life, and thereby allow for less frequent administration.

In some embodiments, the patient to be treated has liver failure or loss of liver function. Liver failure or loss of function can be treated in accordance with this disclosure by administration of a pharmaceutical composition comprising PGE₂ or derivative thereof having similar biological effect. PGE₂ has properties of stimulating liver regeneration. In some embodiments, the liver failure is associated with liver cirrhosis or acute liver damage (e.g. acetaminophen or other chemical toxicity). In another embodiment, the patient to be treated is a liver transplant recipient or liver transplant donor. In some embodiments, the patient to be treated has an alcoholic liver disease or non-alcoholic fatty liver disease (e.g. non-alcoholic steatohepatitis). In another embodiment, the patient has liver fibrosis.

In some embodiments, the patient to be treated may have inflammatory bowel disease (IBD) or ulcerative colitis (UC), which can also benefit from administration of PGE₂ or analogs thereof. In some embodiments, the IBD is Crohn's disease.

Other conditions that may benefit from administration of compositions comprising PGE₂ include irritated stomach (e.g., due to factors such as but not limited to disrupted barrier, stress, acid back-diffusion, alcohol consumption, and/or indomethacin), or conditions in need of hematopoietic stem cell (HSC) out growth (which may promote transplantation efficacy and multilineage reconstitution), conditions in need of osteogenesis and/or bone resorption (e.g., in the case of a bone transplant recipient), excessive pain or hyperalgesia, and asthma. Other conditions applicable to various prostaglandin receptor agonists include those described in U.S. Pat. Nos. 5,703, 108, 6,344,477, 6,437, 146, 6,462,080, 6,462,081, 6,498,172, 6,531,485, 6,545,045, 6,548,544, 6,562,868, 6,610,719, 6,642,266, 6,900,336, 7,271,183, 7,276,531, 7,419,999, 7,442,702, 7,893, 107, and 8,980,944, U.S. Pat. App. Pub. Nos. 2001/0041729, 2002/0044953, 2002/0115695, 2003/0176479, 2004/0142969, 2005/0112075, 2005/0215609, 2007/0232660, 2008/0132543, 2010/135404, 2010/0298436, 2011/0046385, 2012/0283293, 2014/0371147, 2014/0255358, and 2014/0142042, and PCT App. Pub. Nos. WO 1999/019300, WO 1999/002164, WO2004/012656, WO2009/027811, and WO2014/152809, which are all hereby incorporated by reference. Other conditions applicable to various prostaglandin receptor antagonists include those described in one or more of U.S. Pat. Nos. 4,632,928, 5,747,660, 5,955,575, 4,632,928, 5,747,660, 6,369,089, 6,407,250, 6,509,364, 6,511,999, 5,100,889, 5, 153,327, 5,605,917, 6,984,719, 7,273,883, 7,642,249, 8,067,445, 8,404,736, and 8,969,589, U.S. Pat. App. Pub. Nos. 2001/0047027, 2002/0052416, 2005/0065200, 2005/0059742, 2004/0162323, 2008/0275095, 2009/0176804, 2009/0239845, 2010/0256385, 2013/0005741, 2014/0179750, and 2015/0099782, and PCT App. Pub. Nos. WO2001079169 and WO2008039882, which are each hereby incorporated by reference.

In some embodiments, the patient may further receive a prostaglandin-degrading enzyme 15 (15-PGDH) inhibitor, to further elevate prostaglandin levels, or other agent that enhances prostaglandin activity or concentration. In some embodiments, the agent is carbenoxolone. The additional agent may be co-formulated with the prostaglandin receptor agonist as described herein, or administered separately.

In some embodiments, the patient may further undergo treatment with a granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony- stimulating factor (GM-CSF), or a pharmaceutical analog of these factors. The therapy may be via co-formulation or separate administration with the PGE₂ pharmaceutical compositions described herein. G-CSF is a glycoprotein that stimulates the bone marrow to produce granulocytes and stem cells and release them into the bloodstream. The pharmaceutical analogs of naturally occurring G-CSF include filgrastim and lenograstim. G-CSF also stimulates the survival, proliferation, differentiation, and function of neutrophil precursors and mature neutrophils.

In some embodiments, the patient further receives mesalamine formulations, steroid formulations, Jak3 inhibitors or anti-TNF antibody therapy, which may be beneficial in connection with PGE₂ therapy and/or conditions where control of chronic or acute inflammation is particularly needed.

Claims

CLAIMS:

1. A pharmaceutical composition comprising a prostaglandin receptor agonist or antagonist encapsulated in a pharmaceutically acceptable microparticle or nanoparticle carrier.

2. The pharmaceutical composition of claim 1, wherein the prostaglandin receptor agonist or antagonist is released upon degradation of the microparticle or nanoparticle.

3. The pharmaceutical composition of claim 2, wherein degradation is triggered by an endosomal environment.

4. The pharmaceutical composition of claim 3, wherein degradation is triggered by increased concentration of biochemical reductant or by acidic pH.

5. The pharmaceutical composition of claim 2, wherein degradation of the microparticle or nanoparticle occurs outside the cell.

6. The pharmaceutical composition of any one of claims 1 to 5, wherein the microparticle or nanoparticle has a size in the range of about 25 nm to about 500 nm, or in the range of about 50 nm to about 300 nm, or in the range of about 100 nm to about 250 nm.

7. The pharmaceutical composition of any one of claims 1 to 6, wherein the prostaglandin receptor agonist or antagonist is incorporated in the microparticle or nanoparticle non-covalently.

8. The pharmaceutical composition of any one of claims 1 to 6, wherein the prostaglandin receptor agonist or antagonist is incorporated in the microparticle or nanoparticle covalently.

9. The pharmaceutical composition of any one of claims 1 to 8, wherein the microparticle or nanoparticle is polymeric.

10. The pharmaceutical composition of claim 9, wherein the microparticle or nanoparticle comprises a crosslinked interior.

11. The pharmaceutical composition of claim 9, wherein the microparticle or nanoparticle comprises oligoethylene glycol.

12. The pharmaceutical composition of claim 11, wherein the microparticle or nanoparticle carrier degrades in the presence of intracellular concentrations of glutathione (GSH), and the carrier comprises an oligoethylene glycol (OEG) hydrophilic shell and a lipophilic interior comprising disulfide-crosslinked branch groups.

13. The pharmaceutical composition of claim 12, wherein the carrier is formed by self- assembly in an aqueous environment.

14. The pharmaceutical composition of claim 12 or 13, wherein the microparticle or nanoparticle carrier is formed in the presence of the prostaglandin receptor agonist or antagonist and an amphiphilic copolymer, the amphiphilic copolymer comprising hydrophilic oligoethylene glycol branch groups and disulfide-linked lipophilic branch groups to drive micellar assembly and agonist encapsulation, followed by cross-linking of lipophilic branch groups through disulfide exchange reactions.

15. The pharmaceutical composition of claim 14, wherein prostaglandin receptor agonist or antagonist is not substantially released at concentrations of reducing agent characteristic of blood plasma.

16. The pharmaceutical composition of claim 14 or 15, wherein the OEG branch groups have from 5 to 50 ethylene glycol units.

17. The pharmaceutical composition of any one of claims 14 to 16, wherein the lipophilic branch groups comprise pyridyldisulfide (PDS) moieties.

18. The pharmaceutical composition of any one of claims 14 to 17, wherein the OEG branch groups and the lipophilic branch groups are present at a ratio of from 1 :4 to 4: 1.

19. The pharmaceutical composition of claim 18, wherein the amphiphilic co-polymer is prepared by RAFT polymerization of pyridyl disulfide ethyl methacrylate (PDSEMA) and oligoethylene glycol monomethyl ether methacrylate.

20. The pharmaceutical composition of claim 19, wherein the disulfide exchange reaction shuffles sulfhydryl groups of dithiothreitol (DTT) into the disulfides of disulfide- linked lipophilic branch groups.

21. The pharmaceutical composition of claim 20, wherein the crosslinking density of the nanoparticle or microparticle carrier is from 2% to 50%.

22. The pharmaceutical composition of any one of claims 1 to 21, wherein the particle delivery system is described in one or more of US 2014/0112881, US 2015/0202163, US

2015/0209447, and WO/2015/105549, which are hereby incorporated by reference in their entireties.

23. The pharmaceutical composition of claim 9, comprising one or more polymers or copolymers selected from cyclodextrin, poly(D,L-lactic acid-co-glycolic acid) (PLGA), poly(caprolactone) (PCL), ethylene vinyl acetate polymer (EVA), poly(lactic acid) (PLA), poly(L-lactic acid) (PLLA), poly(glycolic acid) (PGA), poly(L-lactic acid-co-glycolic acid) (PLLGA), poly(D,L-lactide) (PDLA), poly(L-Lactide) (PLLA), PLGA-b-poly(ethylene glycol)-PLGA (PLGA-bPEG-PLGA), PLLA-bPEG-PLLA, PLGA-PEG, poly(D,L-lactide- co-caprolactone), poly(D,L-Lactide-co-caprolactone-co-glycolide), poly(D,L-lactide-co- PPO-co-D,L-lactide), polyalkyl cyanoacrylate, polyurethane, poly-L-lysine (PLL), hydroxypropyl methacrylate (HPMA), polyethyleneglycol, poly-L-glutamic acid, poly(hydroxy acids), polyanhydrides, polyorthoesters, poly(ester amides), polyamides, poly(ester ethers), polycarbonates, polyalkylenes, polyalkylene oxides (PEO), polyalkylene terephthalates, polyvinyl alcohols (PVA), polyvinyl ethers, polyvinyl esters such as poly(vinyl acetate), polyvinyl halides such as poly(vinyl chloride) (PVC), polyvinylpyrrolidone, polysiloxanes, polystyrene (PS), derivatized celluloses such as alkyl cellulose, hydroxy alkyl celluloses, cellulose ethers, cellulose esters, nitro celluloses, hydroxypropylcellulose, carboxymethylcellulose, polymers of acrylic acids, such as polymethylmethacrylate) (PMA), poly(ethyl(meth)acrylate), poly(butyl(meth)acrylate), poly (isobutyl (meth)acrylate), poly(hexyl(meth)acrylate), poly(isodecyl(meth)acrylate), poly(lauryl(meth)acrylate), poly(phenyl(meth)acrylate), poly(methyl acrylate), poly(isopropyl acrylate), polyiisobutyl acrylate), poly(octadecyl acrylate) (poly acrylic acids), polydioxanone, polyhydroxyalkanoates, polypropylene fumarate, polyoxymethylene, poloxamers, poly(ortho)esters, poly(butyric acid), poly(valeric acid), poly(lactide-co-caprolactone), trimethylene carbonate, polyvinylpyrrolidone, polyorthoesters, polyphosphazenes, and polyphosphoesters.

24. The pharmaceutical composition of claim 23, comprising PLGA or PLGA-PEG.

25. The pharmaceutical composition of claim 23 or 24, wherein the particle carrier is described in US 8,206,747, which is hereby incorporated by reference in its entirety.

26. The pharmaceutical composition of claim 7 or 8, wherein the particle is a micellar assembly comprising surfactants.

27. The pharmaceutical composition of any one of claims 1 to 26, further comprising a targeting agent.

28. The pharmaceutical composition of claim 27, wherein the targeting agent is an antibody or antigen-binding fragment thereof.

29. The pharmaceutical composition of claim 27, wherein the targeting agent is a peptide, aptamer, adnectin, polysaccharide, or biological ligand.

30. The pharmaceutical composition of claim 27, wherein the targeting agent and target tissues/cells are those listed in Table 1.

31. The pharmaceutical composition of claim 25, wherein the targeting agent is triantennary N- Acetylgalactosamine (GalNAc), dimeric GalNAc or monomeric GalNAc.

32. The pharmaceutical composition of claim 28, wherein the antigen-binding fragment is F(ab')2 or Fab, a single chain antibody, a bi-specific antibody, or a single domain antibody.

33. The pharmaceutical composition of claim 27, wherein the targeting agent binds an integrin, and is optionally RGD peptide.

34. The pharmaceutical composition of claim 27, wherein the targeting agent is a cell- penetrating peptide (CPP).

35. The pharmaceutical composition of claim 27, wherein the ligand is a single-domain antibody, a recombinant heavy-chain-only antibody (VHH), a single-chain antibody (scFv), a shark heavy-chain-only antibody (VNAR), a microprotein (cysteine knot protein, knottin), a DARPin, a Tetranectin, an Affibody; a Transbody, an Anticalin, an AdNectin, an Affilin, a Microbody, a peptide aptamer, a phylomer, a stradobody, a maxibody, an evibody, a fynomer, an armadillo repeat protein, a Kunitz domain, an avimer, an atrimer, a probody, an immunobody, a triomab, a troybody, a pepbody, a vaccibody, a UniBody, a DuoBody, a Fv, a Fab, a Fab', a F(ab')2, a peptide mimetic molecule, or a synthetic molecule, or as described in US Patent Nos. or Patent Publication Nos. US 7,417,130, US 2004/132094, US 5,831,012, US 2004/023334, US 7,250,297, US 6,818,418, US 2004/209243, US 7,838,629, US 7, 186,524, US 6,004,746, US 5,475,096, US 2004/146938, US 2004/157209, US 6,994,982, US 6,794, 144, US 2010/239633, US 7,803,907, US 2010/119446, and/or US 7,166,697, the contents of which are hereby incorporated by reference in their entireties. See also, Storz MAbs. 2011 May-Jun; 3(3): 310-317.

36. The pharmaceutical composition of claim 27, wherein the targeting agent induces receptor-dependent cellular uptake.

37. The pharmaceutical composition of claim 27, wherein the targeting agent induces macropinocytosis-mediated cellular uptake.

38. The pharmaceutical composition of any one of claims 27 to 36, wherein the targeting agent is chemically conjugated to the nanoparticle or microparticle.

39. The pharmaceutical composition of any one of claims 27 to 36, wherein the targeting agent is adsorbed to the surface of the nanoparticle or microparticle.

40. The pharmaceutical composition of claim 27 to 39, wherein the nanoparticle or microparticle is targeted to the liver, kidney, lung, heart, nerves, hematopoietic stem cells, hepatic stellate cells, macrophage, vasculature, brain, vagina, uterus, stomach, intestine (small and large intestine), or muscles of specific organs.

41. The pharmaceutical composition of any one of claims 1 to 26, wherein the nanoparticle or microparticle carrier accumulates in the desired tissue in the absence of a targeting agent.

42. The pharmaceutical composition of claim 41, wherein the tissue is one or more of liver, kidney, or lung.

43. The pharmaceutical composition of any one of claims 1 to 42, wherein the prostaglandin receptor agonist is a prostaglandin.

44. The pharmaceutical composition of claim 43, wherein the prostaglandin is PGE₂.

45. The pharmaceutical composition of any one of claims 1 to 43, wherein the agonist is a PGE₂ derivative, such as Alprostadil.

46. The pharmaceutical composition of claim 44, wherein the derivative is dimethyl- PGE₂.

47. The pharmaceutical composition of claim 44, wherein the derivative is selective for one or more of PGE₂ receptors EP1, EP2, EP3 and EP4.

48. The pharmaceutical composition of any one of claims 1 to 47, formulated for intravenous or intraarterial administration.

49. The pharmaceutical composition of claim 1 to 47, formulated for oral delivery to the GI tract.

50. The pharmaceutical composition of claim 49, comprising an enteric coating.

51. A method for making the pharmaceutical composition of any one of claims 1 to 50, comprising: incorporating the prostaglandin receptor agonist or antagonist into a nanoparticle or microparticle carrier.

52. The method of claim 51, wherein the prostaglandin receptor agonist or antagonist is incorporated as described in one or more of US 2014/0112881, US 2015/0202163, US

53. A method for treating a disease or condition, comprising administering an effective amount of the pharmaceutical composition of any one of claims 1 to 50 to a patient in need.

54. The method of claim 53, wherein the pharmaceutical composition is administered by intravenous or intraarterial administration, oral administration, subcutaneous or direct administration to desired tissues.

55. The method of claim 53 or 54, wherein the pharmaceutical composition is administered from once daily to about once monthly.

56. The method of any one of claims 53 to 55 wherein the patient has liver failure.

57. The method of any one of claims 53 to 56, wherein the patient is a liver transplant recipient, liver transplant donor or has cirrhotic liver disease, alcoholic liver disease, acute liver failure (e.g. acetaminophen or other chemical toxicity), or non-alcoholic fatty liver disease (e.g. non-alcoholic steatohepatitis), or liver fibrosis.

58. The method of any one of claims 53 to 56, wherein the patient has inflammatory bowel disease (IBD) or ulcerative colitis (UC).

59. The method of any one of claims 53 to 55, wherein the patient is an organ transplant recipient or donor.

60. The method of claim 59, wherein the patient is a recipient of bone transplant.

61. The method of any one of claims 53 to 55, wherein the composition is administered to stimulate HSC out growth.

62. The method of any one of claims 53 to 61, wherein the patient further receives a 15-PGDH inhibitor.

63. The method of claim 62, wherein the 15-PGDH inhibitor is encapsulated in the particles, or is administered separately.

64. The method of any one of claims 53 to 61, wherein the patient further receives granulocyte colony-stimulating factor (G-CSF) or granulocyte macrophage colony- stimulating factor (GM-CSF) or a pharmaceutical analog of these factors.

65. The method of any one of claims 53 to 61, wherein the patient further receives mesalamine formulations, steroid formulations, Jak3 inhibitors or anti-TNF antibody therapy.