WO2021011723A1 - Anti-osteoarthritis hydantoin compounds and related compositions and methods - Google Patents

Abstract

This invention provides hydantoin compounds that inhibit both aggrecanase 1 (Adamts4) and aggrecanase 2 (Adamts5). This invention also provides related compositions and methods for treating inflammatory diseases, diseases involving degradation of cartilage, and diseases involving the disruption of cartilage homeostasis.

Description

ANTI-OSTEOARTHRITIS HYDANTOIN COMPOUNDS AND RELATED

COMPOSITIONS AND METHODS

This application claims the benefit of U.S. Serial No. 62/875,568, filed July 18, 2019, and U.S. Serial No. 62/927,878, filed October 30, 2019, the contents of both of which are incorporated herein by reference.

Throughout this application, various publications are cited. The disclosure of these publications is hereby incorporated by reference into this application to describe more fully the state of the art to which this invention pertains.

Field of the Invention

The present invention relates to new compounds and methods of using them to treat joint-related disorders like osteoarthritis.

Background of the Invention

The aggrecan resides in the extracellular matrix of joints. Aggrecanases degrade aggrecan, and contribute to the development of osteoarthritis. Thus, inhibiting aggrecanases is a strategy for treating osteoarthritis.

Lilly’s patent application (WO 2014/066151 ) describes inhibitors of

aggrecanases. Other Lilly publications describe the structure-activity

relationship of certain series of aggrecanase inhibitors. These include, for example, using osmotic pumps to establish pharmacokinetic-pharmacodynamic relationships and define desirable human performance characteristics for aggrecanase inhibitors. They also include identifying potent and selective hydantoin inhibitors of aggrecanase-1 and aggrecanase-2 that are effective in both chemical and surgical models of osteoarthritis. They further include a highly selective hydantoin inhibitor of aggrecanase-1 and aggrecanase-2 with a low projected human dose. Galapagos’ patent applications (e.g., WO 2017/211666, WO 2016/102347, WO 2017/211667, and WO 2017/211668) and Merck’s patents (e.g., U.S. Patent No. 8,859,529) are also germane to aggrecanase inhibitors.

Despite the ongoing interest in developing aggrecanase inhibitors to treat osteoarthritis, there still exists an unmet need in the art for such drugs.

Summary of the Invention

This invention provides a compound having the following structure:

or a pharmaceutically acceptable salt thereof. This invention also provides a prodrug of the present compound, and a pharmaceutically acceptable salt thereof.

This invention further provides the present compound (in both active and prodrug forms), wherein one, two, three, over three, or all hydrogen atoms are replaced by deuterium atoms. This invention also provides a composition comprising the present compound and a pharmaceutically acceptable carrier.

This invention still further provides a method for treating a disorder in a subject comprising administering to the subject a therapeutically effective amount of the present compound, wherein the disorder is selected from the group consisting of osteoarthritis, synovitis, hemophilic arthropathy, rheumatoid arthritis, psoriatic arthritis, juvenile rheumatoid arthritis, gouty arthritis, septic or infectious arthritis, reactive arthritis, reflex sympathetic dystrophy, scleroderma, ankylosing spondylitis, algodystrophy, achondroplasia, Paget’s disease, Tietze syndrome or costal chondritis, fibromyalgia, neurogenic or neuropathic arthritis, arthropathy, sarcoidosis, amylosis, cartilage injury, hydarthrosis, periodical disease, rheumatoid spondylitis, osteochondritis dissecans, hypertropic arthritis, Yersinia arthritis, pyrophosphate arthritis, an endemic form of arthritis, fibromyalgia, systemic lupus erythematosus, scleroderma, ankylosing spondylitis,

degenerative disc disease, hip dysplasia, osteochondrosis, elbow dysplasia, and joint injury caused by trauma.

This invention provides a biodegradable microsphere, wherein the microsphere (i) has a diameter of from 1 pm to 500 pm; (ii) comprises a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carries the present compound; and (iv) when present in a suitable joint-related tissue, releases the compound for at least one month.

This invention also provides a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

This invention provides an injectable formulation comprising (a) a

pharmaceutically acceptable carrier and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

This invention also provides a method for treating a joint-related disorder in a subject comprising introducing biodegradable microspheres into suitable tissue in or around one or more of the subject’s joints, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

Finally, this invention further provides an article of manufacture (kit) comprising, in separate compartments, (a) a diluent, and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

Brief Description of the Fiqures

Figures 1A and 1 B

These figures show the inhibitory activity of the active form of the present compound on Aggrecanase 1 (Adamts4) (IC50 = 13.5 nM) (Figure 1A) and Aggrecanase 2 (Adamts5) (IC50 = 15.2 nM) (Figure 1 B).

Figures 2A and 2B

These figures show the inhibitory activity of the active form of the present compound on MMP1 (IC50 = 1.94 mM) (Figure 2A) and MMP2 (IC50 = 12.9 pM) (Figure 2B).

Figures 3A and 3B

These figures show the inhibitory activity of the active form of the present compound on MMP3 (IC50 = 1 pM) (Figure 3A) and MMP7 (IC50 = 144.6 pM) (Figure 3B).

Figures 4A and 4B

These figures show the inhibitory activity of the active form of the present compound on MMP8 (IC50 = 455 nM) (Figure 4A) and MMP9 (IC50 = 12.2 pM) (Figure 4B). Figures 5A and 5B

These figures show the inhibitory activity of the active form of the present compound on MMP12 (IC50 = 43 nM) (Figure 5A) and MMP13 (IC50 = 2.1 mM) (Figure 5B).

Figures 6A and 6B

These figures show the inhibitory activity of the active form of the present compound on MMP14 (IC50 = 4.2 pM) (Figure 6A) and TACE (IC50 = 13.6 pM) (Figure 6B).

Figure 7

This figure shows the inhibitory activity of the active form of the present compound on glycosaminoglycan (GAG) release by human healthy

chondrocytes. The EC50 for inhibiting GAG release (indicating activity of cartilage degradation) is 37.8 nM.

Figure 8

This figure shows the FI-NMR spectrum of the active form of the present compound.

Detailed Description of the Invention

This invention provides new compounds and methods of using them to treat joint-related disorders like osteoarthritis, as well as numerous other disorders.

Definitions

In this application, certain terms are used which shall have the meanings set forth as follows.

In this invention, each present compound is preferably“administered” (also referred to as“introduced”) in the form of a pharmaceutical composition (i.e. , the compound (alone or as a pharmaceutically acceptable salt) in combination with a pharmaceutically acceptable carrier). Administering the instant pharmaceutical compositions can be effected or performed using any of the various methods and delivery systems known to those skilled in the art. The administering can be performed, for example, intravenously, orally, intra- articularly, via implant, transmucosally, transdermally, intramuscularly, and subcutaneously. In addition, pharmaceutically acceptable carriers are well known to those skilled in the art (including, e.g., the diluents disclosed herein). The following delivery systems, which employ a number of routinely used carriers, are only representative of the many embodiments envisioned for administering the instant compositions.

Oral delivery systems include, for example, tablets and capsules. These can contain excipients such as binders (e.g., hydroxypropylmethylcellulose, polyvinyl pyrilodone, other cellulosic materials and starch), diluents (e.g., lactose and other sugars, starch, dicalcium phosphate and cellulosic materials),

disintegrating agents (e.g., starch polymers and cellulosic materials) and lubricating agents (e.g., stearates and talc). Solutions, suspensions and powders for reconstitutable delivery systems include vehicles such as

suspending agents (e.g., gums, zanthans, cellulosics and sugars), humectants (e.g., sorbitol), solubilizers (e.g., ethanol, water, PEG and propylene glycol), surfactants (e.g., sodium lauryl sulfate, Spans, Tweens, and cetyl pyridine), preservatives and antioxidants (e.g., parabens, vitamins E and C, and ascorbic acid), anti-caking agents, coating agents, and chelating agents (e.g.,

EDTA). Transdermal delivery systems include patches, gels, tapes and creams, and can contain excipients such as solubilizers, permeation enhancers (e.g., fatty acids, fatty acid esters, fatty alcohols and amino acids), hydrophilic polymers (e.g., polycarbophil and polyvinylpyrolidone), and adhesives and tackifiers (e.g., polyisobutylenes, silicone-based adhesives, acrylates and polybutene). Transmucosal delivery systems include patches, tablets, suppositories, pessaries, gels and creams, and can contain excipients such as solubilizers and enhancers (e.g., propylene glycol, bile salts and amino acids), and other vehicles (e.g., polyethylene glycol, fatty acid esters and derivatives, and hydrophilic polymers such as hydroxypropyl-methylcellulose and hyaluronic acid). Injectable drug delivery systems include solutions, suspensions, gels, microspheres (detailed herein) and polymeric injectables, and can comprise excipients such as solubility-altering agents (e.g., ethanol, propylene glycol and sucrose) and polymers (e.g., polycaprylactones and PLGA's). Implantable systems include rods and discs, and can contain excipients such as PLGA and polycaprylactone. In the case of biodegradable microspheres,“introducing” preferably means delivering to a specified part of the body, such as joint fluid or a disc. Methods of introducing biodegradable microspheres to joint fluid are known and include, for example, intra-articular injection. See, e.g., the Zilretta^® label. Methods for injecting biodegradable microspheres into discs can be performed based on known animal studies. For example, polyester amide microspheres were injected to the intervertebral discs in a canine model of disc degeneration, and were shown to have good cytocompatability and

biocompatibility. In a rat discitis model, intra-discal vancomycin-loaded PLGA microspheres were shown to control and reduce infective discitis, with superior efficacy to intravenous vancomycin. See, e.g., Williems, et al. , and Wang, et al.

The instant pharmaceutical compositions can be packaged in the form of pharmaceutical kits or packages in which the daily (or other periodic) dosages are arranged for proper sequential administration. Accordingly, this invention further provides a drug delivery system comprising a pharmaceutical package containing a plurality of dosage units, adapted for successive daily (or other periodic) administration (e.g., oral administration), each dosage unit comprising at least one of the instant pharmaceutical compositions.

As used herein, a“biodegradable microsphere” comprises a polylactic-co- glycolic acid copolymer (PLGA) matrix, which matrix can include solely polylactic acid (PLA), solely polyglycolic acid (PGA), or a combination of PLA and PGA. For certain PLA to PGA ratios (e.g., 50:50 to 100:0), the higher a microsphere’s PLA content, the slower it degrades and, thus, the more stable it is. Conversely, for such ratios, the higher a microsphere’s PGA content, the faster it degrades and the less stable it is. In one embodiment, the

biodegradable microsphere contains a combination of PLA and PGA wherein the molar ratio of PLA to PGA (i.e. , the“lactic acid to glycolic acid ratio”, or“L:G ratio”) is 0:100, 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, 95:5, or 100:0. In another embodiment, the biodegradable microsphere contains a combination of PLA and PGA wherein the molar ratio of PLA to PGA is from 5:95 to 20:80, from 20:80 to 40:60, from 40:60 to 50:50, from 50:50 to 60:40, from 60:40 to 80:20, from 80:20 to 100:0, from 50:50 to 100:0, from 60:40 to 90:10, from 70:30 to 80:20, from 50:50 to 80:20, from 50:50 to 90:10, from 60:40 to 70:30, from 80:20 to 90: 10, or from 90: 10 to 100:00. The population of biodegradable microspheres used in this invention can be homogeneous or heterogeneous with respect to the microspheres’ molar ratio of PLA to PGA. In one

embodiment, the population of biodegradable microspheres is homogeneous with respect to the microspheres’ molar ratio of PLA to PGA (e.g., the population includes only microspheres wherein the molar ratio of PLA to PGA is at least 75:25). In another embodiment, the population of biodegradable microspheres is heterogeneous (e.g., the population includes both (i) microspheres wherein the molar ratio of PLA to PGA is 70:30, and (ii) microspheres wherein the molar ratio of PLA to PGA is 80:20). In a preferred embodiment, the instant microspheres contain PLGA having an inherent viscosity of 0.1 to 2.0 dl/g (e.g., 0.16 to 1.7 dl/g), and a molecular weight from 1 ,000 to 500,000 (e.g., from 7,000 to 240,000).

The present biodegradable microsphere has a diameter of, for example, from 1 pm to 500 pm, (ii) can non-covalently carry the present compound, and (iii) depending on its polymeric composition, degrades over a period lasting, for example, from one month to over twelve months when placed in suitable joint- related tissue. Microsphere diameters (and d9o values) include, for example, the following: (i) from 1 pm to 20 pm, from 20 pm to 40 pm, from 40 pm to 60 pm, from 60 pm to 80 pm, from 80 pm to 100 pm, from 100 pm to 120 pm, from 120 pm to 140 pm, from 140 pm to 160 pm, from 160 pm to 180 pm, from 180 pm to 200 pm, from 200 pm to 250 pm, from 250 pm to 300 pm, from 300 pm to 350 pm, from 350 pm to 400 pm, from 400 pm to 450 pm, or from 450 pm to 500 pm; and (ii) 20 pm, 40 pm, 60 pm, 80 pm, 100 pm, 120 pm, 140 pm, 160 pm, 180 pm, 200 pm, 250 pm, 300 pm, 350 pm, 400 pm, 450 pm, or 500 pm. The present biodegradable microspheres can further comprise polyethylene glycol (PEG). Biodegradable PLGA microspheres (including homogeneous and heterogeneous populations thereof having defined molar ratios of PLA to PGA) are commercially available from, among other sources, Millipore-Sigma in the form of Degradex^® products (Burlington, MA).

As used herein, the term“carry”, with respect to the present compound and a biodegradable microsphere, means that the present compound is non- covalently bound to, or otherwise contained in or on, the biodegradable microsphere in a manner permitting release from the microsphere during its biodegradation.

As used herein, the term“diluent” includes, without limitation,

carboxymethylcellulose sodium, mannitol (which can optionally be incorporated on and/or into the microspheres to improve suspendability), and water.

As used herein, the term“d9o value”, with respect to a population of

biodegradable microspheres having a specified size range, means that 90% of the biodegradable microspheres have a diameter in the specified range.

As used herein, a“pharmaceutically acceptable salt” includes, without limitation, a salt formed by any of the following acids: 1-hydroxy-2-naphthoic acid, 2,2- dichloroacetic acid, 2-hydroxyethanesulfonic acid, 2-oxoglutaric acid, 4- acetamidobenzoic acid, 4-aminosalicylic acid, acetic acid, adipic acid, ascorbic acid (L), aspartic acid (L), benzenesulfonic acid, benzoic acid, camphoric acid (+), camphor-10-sulfonic acid (+), capric acid (decanoic acid), caproic acid (hexanoic acid), caprylic acid (octanoic acid), carbonic acid, cinnamic acid, citric acid, cyclamic acid, dodecylsulfuric acid, ethane-1 ,2-disulfonic

acid, ethanesulfonic acid, formic acid, fumaric acid, galactaric acid, gentisic acid, glucoheptonic acid (D), gluconic acid (D), glucuronic acid (D), glutamic acid, glutaric acid, glycerophosphoric acid, glycolic acid, hippuric

acid, hydrobromic acid, hydrochloric acid, isobutyric acid, lactic acid

(DL), lactobionic acid, lauric acid, maleic acid, malic acid (- L), malonic acid, mandelic acid (DL), methanesulfonic acid, naphthalene-1 ,5-disulfonic acid, naphthalene-2-sulfonic acid, nicotinic acid, nitric acid, oleic acid, oxalic acid, palmitic acid, pamoic acid, phosphoric acid, proprionic acid, pyroglutamic acid (- L), salicylic acid, sebacic acid, stearic acid, succinic acid, sulfuric acid, tartaric acid (+ L), thiocyanic acid, toluenesulfonic acid (p), or undecylenic acid.

As used herein, a“prodrug” is a biologically inactive form of a drug that, when metabolized in the body, yields the active form of the drug. In the active form of the present compound, both hydantoin hydrogen atoms (i.e., the hydrogen atoms on the five-membered hydantoin ring) are present. By way of example, in the prodrug form of the present compound, one or both of the hydantoin hydrogen atoms are replaced with a prodrug moiety. In one embodiment, each of the hydantoin hydrogen atoms is replaced with a prodrug moiety, and these moieties may be the same or different. Preferably, only one of the hydantoin hydrogen atoms is replaced with a prodrug moiety. Preferably, the hydantoin hydrogen atom bound to the ring nitrogen atom in turn bound to the two carbonyl groups (referred to herein as the“preferred hydantoin hydrogen atom”) is replaced with a prodrug moiety. In another embodiment, the other hydantoin hydrogen atom is replaced with a prodrug moiety.

Prodrug moieties include, without limitation, ester groups (e.g., with a CH₂ linker), and sulfonamide groups. Prodrug moieties that can replace one or more of the hydantoin hydrogen atoms (ideally the preferred hydantoin hydrogen atom) of the present compound are exemplified below, wherein the present compound is represented by the following formula:

In this formula, the active form of the present compound is shown when both R₂ moieties are H (i.e., when both hydantoin hydrogen atoms are present). The prodrug form is shown when at least one R₂ moiety is not H. Thus, the prodrug form of the present compound can be described, for example, as follows: one or both R2 moieties is selected from the group consisting of pivalate, tridecanoate, ethyl carbonate, 5-methylene-4-methyl-1 ,3-dioxol-2-one, methylene-2-ethoxy-2- methylpropanoate, tert-butylthio, 2-(tert-butyldisulfaneyl)ethyl, ethyl (2- (disulfaneyl)ethyl) carbonate, glutathione,— C0(P=0)(0R⁷)₂, and— CX

(wherein X represents the three substituents R⁴, R⁴, and (Q)_nR⁵, and each of these three substituents is attached to the carbon atom), wherein (i) each R⁴ is the same or different and is independently selected from the group consisting of

H, deuterium, alkyl, and aryl, or the two R⁴ substituents taken together with the carbon atom to which they are attached is— C(=0)— ; (ii) R⁵ is selected from the group consisting of H, alkyl, alkyl substituted with— O-alkyl-O-alkyl-O-alkyl, alkyl substituted with heterocyclyl, alkyl substituted with aryl, heterocyclyl, aryl, heteroaryl,— C(=0)N(R⁷)₂,— C(=0)-alkyl,— C(=0)-alkyl substituted on the alkyl with— O-alkyl-O-alkyl,— C(=0)-cycloalkyl,— C(=0)-heterocyclyl,—

C(=0)-aryl,— C(=0)-heteroaryl,— C(=0)— O-alkyl,— C(=0)— O-alkyl substituted on the alkyl with— N(R⁷)2,— C(=0)— O-alkyl substituted on the alkyl with— C(=0)— O-alkyl,— C(=0)— O-alkyl substituted on the alkyl with—

N(R⁷)— C(=0)-alkyl-aryl,— C(=0)— O-alkyl substituted on the alkyl with heterocyclyl,— C(=0)-p-cycloalkyl,— C(=0)— O-heterocyclyl,— C(=0)— O-aryl, — C(=0)— O-heteroaryl,— P(=0)(— OH)2,— P(=0)(— 0-alkyl)₂, wherein when each of the cycloalkyl, heterocyclyl, aryl, or heteroaryl in any R⁵ group contains two radicals on adjacent carbon atoms, the radicals may optionally be taken together with the carbon atoms to which they are attached to form a five- or six- membered cycloalkyl, aryl, heterocyclyl or heteroaryl ring; (iii) Q is selected from the group consisting of— NR⁷— ,— O— ,— S— ,— S(O)— , and— S(0)₂— ; (iv) each R⁷ is the same or different and is independently H or alkyl; and (v) n is 0 or

I .

As used herein, a biodegradable microsphere“releases” the present compound when some, or all, of the present compound contained by the microsphere is freed into the microsphere’s surrounding milieu. Preferably, the release is continuous. For example, in a plurality of present compound-carrying

biodegradable microspheres having an average release per day of X mg, the present compound released per day is, e.g., from 0.1X mg to 10X mg, from 0.2X mg to 5X mg, or from 0.5X mg to 2X mg. In another example, in a plurality of present compound-carrying biodegradable microspheres having an average release per week of X mg, the present compound released per week is, e.g., from 0.2X mg to 5X mg, or from 0.5X mg to 2X mg. In one embodiment, present compound release into the joint-related tissue precedes, and is distinct from, its efficacy (e.g., pain relief or improvement in physical function) in that tissue. For example, biodegradable microspheres that release a therapeutically effective amount of pharmaceutical present compound into a joint’s synovial fluid for two months might yield a therapeutic effect for three months. In another embodiment, present compound release into the joint-related tissue is

concomitant with its efficacy (e.g., the preservation of joint cartilage) in that tissue.

As used herein, the term“subject” includes, without limitation, a mammal such as a human, a non-human primate, a dog, a cat, a horse, a sheep, a goat, a cow, a rabbit, a pig, a rat and a mouse. Preferably, the subject is human. In another embodiment, the subject is a dog, a cat, or a horse.

As used herein, the phrase“suitable joint-related tissue” includes any portion of a joint, or the joint’s surrounding tissue, which is capable of holding the instant present compound-containing biodegradable microspheres such that the present compound released therefrom can act on the joint. Suitable joint- related tissue includes, without limitation, (i) articular and periarticular spaces;

(ii) the bursa, synovial cavity, joint capsule with synovial lining, and the fluids contained therein; and (iii) connective and contractile tissue (e.g., articular cartilage, ligaments, tendons and muscles).

As used herein,“treating” a subject afflicted with a disorder shall include, without limitation, (i) slowing, stopping or reversing the disorder's progression, (ii) slowing, stopping or reversing the progression of the disorder’s symptoms (e.g., pain), (iii) reducing the likelihood of the disorder’s recurrence, and/or (iv) reducing the likelihood that the disorder’s symptoms will recur. In the preferred embodiment, treating a subject afflicted with a disorder means (i) reversing the disorder's progression, ideally to the point of eliminating the disorder, and/or (ii) reversing the progression of the disorder’s symptoms, ideally to the point of eliminating the symptoms.

Embodiments of the Invention

This invention solves an unmet need in the art by providing novel hydantoin compounds to treat disorders like osteoarthritis. These compounds inhibit both aggrecanase 1 (Adamts4) and aggrecanase 2 (Adamts5). This invention also provides related compositions for systemic delivery (such as tablets and capsules) and those for local delivery (such as biodegradable microsphere compositions), as well as methods and kits for treating inflammatory diseases, diseases involving degradation of cartilage, and diseases involving the disruption of cartilage homeostasis.

Specifically, this invention provides a compound having the following structure:

or a pharmaceutically acceptable salt thereof.

Pharmaceutically acceptable salts of the active form of the present compound (represented in this paragraph by“X”) include, without limitation, the following: a salt of X formed by 1 -hydroxy-2-naphthoic acid; a salt of X formed by 2,2- dichloroacetic acid; a salt of X formed by 2-hydroxyethanesulfonic acid; a salt of X formed by 2-oxoglutaric acid; a salt of X formed by 4-acetamidobenzoic acid; a salt of X formed by 4-aminosalicylic acid; a salt of X formed by acetic acid; a salt of X formed by adipic acid; a salt of X formed by ascorbic acid (L); a salt of X formed by aspartic acid (L); a salt of X formed by benzenesulfonic acid; a salt of X formed by benzoic acid; a salt of X formed by camphoric acid (+); a salt of X formed by camphor-10-sulfonic acid (+); a salt of X formed by capric acid (decanoic acid); a salt of X formed by caproic acid (hexanoic acid); a salt of X formed by caprylic acid (octanoic acid); a salt of X formed by carbonic acid; a salt of X formed by cinnamic acid; a salt of X formed by citric acid; a salt of X formed by cyclamic acid; a salt of X formed by dodecylsulfuric acid; a salt of X formed by ethane-1 ,2-disulfonic acid; a salt of X formed by ethanesulfonic acid; a salt of X formed by formic acid; a salt of X formed by fumaric acid; a salt of X formed by galactaric acid; a salt of X formed by gentisic acid; a salt of X formed by glucoheptonic acid (D); a salt of X formed by gluconic acid (D); a salt of X formed by glucuronic acid (D); a salt of X formed by glutamic acid; a salt of X formed by glutaric acid; a salt of X formed by glycerophosphoric acid; a salt of X formed by glycolic acid; a salt of X formed by hippuric acid; a salt of X formed by hydrobromic acid; a salt of X formed by hydrochloric acid; a salt of X formed by isobutyric acid; a salt of X formed by lactic acid (DL); a salt of X formed by lactobionic acid; a salt of X formed by lauric acid; a salt of X formed by maleic acid; a salt of X formed by malic acid (- L); a salt of X formed by malonic acid; a salt of X formed by mandelic acid (DL); a salt of X formed by methanesulfonic acid; a salt of X formed by naphthalene-1 ,5-disulfonic acid; a salt of X formed by naphthalene-2-sulfonic acid; a salt of X formed by nicotinic acid; a salt of X formed by nitric acid; a salt of X formed by oleic acid; a salt of X formed by oxalic acid; a salt of X formed by palmitic acid; a salt of X formed by pamoic acid; a salt of X formed by phosphoric acid; a salt of X formed by proprionic acid; a salt of X formed by pyroglutamic acid (- L); a salt of X formed by salicylic acid; a salt of X formed by sebacic acid; a salt of X formed by stearic acid; a salt of X formed by succinic acid; a salt of X formed by sulfuric acid; a salt of X formed by tartaric acid (+ L); a salt of X formed by thiocyanic acid; a salt of X formed by toluenesulfonic acid (p); a salt of X formed by and undecylenic acid.

This compound (and its salt forms) is referred to herein as the“active form” of the present compound, or simply the“present active form.” This invention also provides a prodrug of the compound having the following structure:

or a pharmaceutically acceptable salt thereof.

This compound is referred to herein as the“prodrug form” of the present compound, or simply the“present prodrug form.” The active and prodrug forms of the present compound are collectively referred to herein as the“present compound” or the“present compounds.”

This invention further provides the present compound (in both active and prodrug forms), wherein one, two, three, over three, or all hydrogen atoms are replaced by deuterium atoms.

This invention further provides a composition comprising the present compound (preferably the present prodrug form) and a pharmaceutically acceptable carrier. In one embodiment, the present composition is formulated for oral

administration. In another embodiment, the present composition is formulated for intravenous administration. In a further embodiment, the present

composition is formulated for injection into a joint or a disc.

The present compound is envisioned for use, without limitation, in the

prophylaxis and/or treatment of inflammatory diseases, and/or diseases involving degradation of cartilage and/or disruption of cartilage homeostasis. This invention provides a method for treating a disorder in a human subject comprising administering to the subject a therapeutically effective amount of the present compound (preferably the present prodrug form), wherein the disorder is selected from the group consisting of osteoarthritis, synovitis, hemophilic arthropathy, rheumatoid arthritis, psoriatic arthritis, juvenile rheumatoid arthritis, gouty arthritis, septic or infectious arthritis, reactive arthritis, reflex sympathetic dystrophy, scleroderma, ankylosing spondylitis, algodystrophy, achondroplasia, Paget’s disease, Tietze syndrome or costal chondritis, fibromyalgia, neurogenic or neuropathic arthritis, arthropathy, sarcoidosis, amylosis, cartilage injury, hydarthrosis, periodical disease, rheumatoid spondylitis, osteochondritis dissecans, hypertropic arthritis, Yersinia arthritis, pyrophosphate arthritis, an endemic form of arthritis, fibromyalgia, systemic lupus erythematosus, scleroderma, ankylosing spondylitis, degenerative disc disease, joint injury caused by trauma, and cartilage degeneration associated with steroid use (e.g., cortisone use).

This invention also provides a method for treating a disorder in a non-human mammal (preferably a cat, a dog, or a horse) comprising administering to the mammal a therapeutically effective amount of the present compound (preferably the present prodrug form), wherein the disorder is selected from the group consisting of osteoarthritis, synovitis, hemophilic arthropathy, rheumatoid arthritis, psoriatic arthritis, juvenile rheumatoid arthritis, gouty arthritis, septic or infectious arthritis, reactive arthritis, reflex sympathetic dystrophy, scleroderma, ankylosing spondylitis, algodystrophy, achondroplasia, Paget’s disease, Tietze syndrome or costal chondritis, fibromyalgia, neurogenic or neuropathic arthritis, arthropathy, sarcoidosis, amylosis, cartilage injury, hydarthrosis, periodical disease, rheumatoid spondylitis, osteochondritis dissecans, hypertropic arthritis, Yersinia arthritis, pyrophosphate arthritis, an endemic form of arthritis, fibromyalgia, systemic lupus erythematosus, scleroderma, ankylosing

spondylitis, degenerative disc disease, hip dysplasia, osteochondrosis, elbow dysplasia, and joint injury caused by trauma.

In the present methods, for systemic delivery (e.g., oral, intravenous, or subcutaneous), the envisioned dosages include, for example, 0.1 mg - 10 g per day. By way of example, dosages of the present compound (i.e. , therapeutically effective amounts) for oral delivery (e.g., daily delivery) include, without limitation, the following: (i) 0.1 mg, 0.15 mg, 0.2 mg, 0.25 mg, 0.3 mg, 0.35 mg, 0.4 mg, 0.45 mg, 0.5 mg, 0.55 mg, 0.6 mg, 0.65 mg, 0.7 mg, 0.75 mg, 0.8 mg, 0.85 mg, 0.9 mg, 0.95 mg, 1 mg, 1 .5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg, 5 mg, 5.5 mg, 6 mg, 6.5 mg, 7 mg, 7.5 mg, 8 mg, 8.5 mg, 9 mg, 9.5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, 500 mg, 550 mg, 600 mg, 650 mg, 700 mg, 750 mg, 800 mg, 850 mg, 900 mg, 950 mg, 1 g, 1 .5 g, 2 g, 2.5 g, 3 g,

3.5 g, 4 g, 4.5 g, 5 g, 5.5 g, 6 g, 6.5 g, 7 g, 7.5 g, 8 g, 8.5 g, 9 g, 9.5 g, or 10 g;

(ii) from 0.1 mg to 1 mg, from 1 mg to 25 mg, from 25 mg to 50 mg, from 50 mg to 75 mg, from 75 mg to 100 mg, from 100 mg to 150 mg, from 150 mg to 200 mg, from 200 mg to 250 mg, from 250 mg to 300 mg, from 300 mg to 350 mg, from 350 mg to 400 mg, from 400 mg to 450 mg, from 450 mg to 500 mg, from 500 mg to 550 mg, from 550 mg to 600 mg, from 600 mg to 650 mg, from 650 mg to 700 mg, from 700 mg to 750 mg, from 750 mg to 800 mg, from 800 mg to 850 mg, from 850 mg to 900 mg, from 900 mg to 950 mg, from 950 mg to 1 g, from 1 g to 2 g, from 2 g to 3 g, from 3 g to 4 g, from 4 g to 5 g, from 5 g to 6 g, from 6 g to 7 g, from 7 g to 8 g, from 8 g to 9 g, or from 9 g to 10 g; or (iii) from 0.1 mg to 250 mg, from 250 mg to 500 mg, from 500 mg to 1 g, or from 1 g to 10 9

Dosages of the present compound (i.e., therapeutically effective amounts) for intravenous delivery (e.g., daily delivery) include, without limitation, the following: (i) 0.1 mg, 0.15 mg, 0.2 mg, 0.25 mg, 0.3 mg, 0.35 mg, 0.4 mg, 0.45 mg, 0.5 mg, 0.55 mg, 0.6 mg, 0.65 mg, 0.7 mg, 0.75 mg, 0.8 mg, 0.85 mg, 0.9 mg, 0.95 mg, 1 mg, 1 .5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg, 5 mg,

5.5 mg, 6 mg, 6.5 mg, 7 mg, 7.5 mg, 8 mg, 8.5 mg, 9 mg, 9.5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, 500 mg, 550 mg, 600 mg, 650 mg, 700 mg, 750 mg, 800 mg, 850 mg, 900 mg, 950 mg, 1 g, 1 .5 g, 2 g, 2.5 g, 3 g, 3.5 g, 4 g,

4.5 g, 5 g, 5.5 g, 6 g, 6.5 g, 7 g, 7.5 g, 8 g, 8.5 g, 9 g, 9.5 g, or 10 g; (ii) from 0.1 mg to 1 mg, from 1 mg to 25 mg, from 25 mg to 50 mg, from 50 mg to 75 mg, from 75 mg to 100 mg, from 100 mg to 150 mg, from 150 mg to 200 mg, from 200 mg to 250 mg, from 250 mg to 300 mg, from 300 mg to 350 mg, from 350 mg to 400 mg, from 400 mg to 450 mg, from 450 mg to 500 mg, from 500 mg to 550 mg, from 550 mg to 600 mg, from 600 mg to 650 mg, from 650 mg to 700 mg, from 700 mg to 750 mg, from 750 mg to 800 mg, from 800 mg to 850 mg, from 850 mg to 900 mg, from 900 mg to 950 mg, from 950 mg to 1 g, from 1 g to 2 g, from 2 g to 3 g, from 3 g to 4 g, from 4 g to 5 g, from 5 g to 6 g, from 6 g to 7 g, from 7 g to 8 g, from 8 g to 9 g, or from 9 g to 10 g; or (iii) from 0.1 mg to 250 mg, from 250 mg to 500 mg, from 500 mg to 1 g, or from 1 g to 10 g.

Dosages of the present compound (i.e. , therapeutically effective amounts) for subcutaneous delivery (e.g., daily delivery) include, without limitation, the following: (i) 0.1 mg, 0.15 mg, 0.2 mg, 0.25 mg, 0.3 mg, 0.35 mg, 0.4 mg, 0.45 mg, 0.5 mg, 0.55 mg, 0.6 mg, 0.65 mg, 0.7 mg, 0.75 mg, 0.8 mg, 0.85 mg, 0.9 mg, 0.95 mg, 1 mg, 1 .5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg, 5 mg,

5.5 mg, 6 mg, 6.5 mg, 7 mg, 7.5 mg, 8 mg, 8.5 mg, 9 mg, 9.5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, 500 mg, 550 mg, 600 mg, 650 mg, 700 mg, 750 mg, 800 mg, 850 mg, 900 mg, 950 mg, 1 g, 1 .5 g, 2 g, 2.5 g, 3 g, 3.5 g, 4 g,

4.5 g, 5 g, 5.5 g, 6 g, 6.5 g, 7 g, 7.5 g, 8 g, 8.5 g, 9 g, 9.5 g, or 10 g; (ii) from 0.1 mg to 1 mg, from 1 mg to 25 mg, from 25 mg to 50 mg, from 50 mg to 75 mg, from 75 mg to 100 mg, from 100 mg to 150 mg, from 150 mg to 200 mg, from 200 mg to 250 mg, from 250 mg to 300 mg, from 300 mg to 350 mg, from 350 mg to 400 mg, from 400 mg to 450 mg, from 450 mg to 500 mg, from 500 mg to 550 mg, from 550 mg to 600 mg, from 600 mg to 650 mg, from 650 mg to 700 mg, from 700 mg to 750 mg, from 750 mg to 800 mg, from 800 mg to 850 mg, from 850 mg to 900 mg, from 900 mg to 950 mg, from 950 mg to 1 g, from 1 g to 2 g, from 2 g to 3 g, from 3 g to 4 g, from 4 g to 5 g, from 5 g to 6 g, from 6 g to

7 g, from 7 g to 8 g, from 8 g to 9 g, or from 9 g to 10 g; or (iii) from 0.1 mg to 250 mg, from 250 mg to 500 mg, from 500 mg to 1 g, or from 1 g to 10 g. By way of example, per injection dosages of the present compound (i.e. , therapeutically effective amounts) for local intra-articular delivery to the knee or intra disc delivery include, without limitation, the following: (i) 1 mg, 1.5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg, 5 mg, 5.5 mg, 6 mg, 6.5 mg, 7 mg, 7.5 mg, 8 mg, 8.5 mg, 9 mg, 9.5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, or 500 mg; (ii) from 1 mg to 25 mg, from 25 mg to 50 mg, from 50 mg to 75 mg, from 75 mg to 100 mg, from 100 mg to 150 mg, from 150 mg to 200 mg, from 200 mg to 250 mg, from 250 mg to 300 mg, from 300 mg to 350 mg, from 350 mg to 400 mg, from 400 mg to 450 mg, or from 450 mg to 500 mg; or (iii) from 1 mg to 250 mg, or from 250 mg to 500 mg.

In another embodiment of this invention, the present compound is locally administered in the form of biodegradable microspheres. So, this invention provides a biodegradable microsphere, wherein the microsphere (i) has a diameter of from 1 pm to 500 pm; (ii) comprises a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carries the present compound (preferably the present prodrug form); and (iv) when present in a suitable joint-related tissue, releases the compound for at least one month.

In one embodiment, the present biodegradable microsphere has a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50. In another embodiment, the present biodegradable microsphere (i) has a diameter of from 20 pm to 200 pm; and (ii) has a lactic acid to glycolic acid molar ratio of at least 75:25 (e.g., 75:25, 80:20, 85:15, 90:10, 95:5, or 100:0). In yet another embodiment, the present biodegradable microsphere further comprises polyethylene glycol (PEG).

In yet another embodiment of the present biodegradable microsphere, when it is present in a suitable joint-related tissue, it releases the present compound for longer than one month. Preferably, the microsphere, when present in a suitable joint-related tissue, releases the present compound for at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months.

This invention provides a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound (preferably the present prodrug form); and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

In one embodiment, the present plurality of biodegradable microspheres further comprise polyethylene glycol (PEG).

In another embodiment, the present plurality of biodegradable microspheres (i) have a d9o value from 20 pm to 200 pm; (ii) have a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50; and (iii) carry from 1 mg to 500 mg of the compound.

In another embodiment of the present plurality of biodegradable microspheres, the microspheres, when present in a suitable joint-related tissue, release the present compound for longer than one month. Preferably, the microspheres, when present in a suitable joint-related tissue, releases the present compound for at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months.

This invention provides an injectable formulation comprising (a) a

pharmaceutically acceptable carrier and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound (preferably the present prodrug form); and (iv) when present in a suitable joint-related tissue, release the compound for at least one month (and optionally release the present compound at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months). In one embodiment of the present formulation, the microspheres further comprises polyethylene glycol (PEG).

This invention provides a method for treating a joint-related disorder in a subject comprising introducing biodegradable microspheres into suitable tissue in or around one or more of the subject’s joints, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the present compound (preferably the present prodrug form); and (iv) when present in a suitable joint-related tissue, release the compound for at least one month (and optionally release the present compound for at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months).

Preferably, the present microspheres further comprise polyethylene glycol (PEG).

In one embodiment of this method, the subject is human. In another

embodiment, the subject is a non-human mammal (preferably a cat, a dog, or a horse).

In one embodiment of this method, the disorder is arthritis, such as osteoarthritis or rheumatoid arthritis.

In a preferred embodiment, this method comprises intra-articularly injecting the biodegradable microspheres into one or both of the subject’s knees.

In another preferred embodiment of this method, the microspheres (i) have a d9o value from 20 pm to 200 pm; (ii) have a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50; and (iii) carry from 1 mg to 500 mg of the compound. In another preferred embodiment of this method, the microspheres have an average lactic acid to glycolic acid molar ratio of at least 75:25 (e.g., 75:25, 80:20, 85:15, 90:10, 95:5, or 100:0).

In another preferred embodiment of this method, the biodegradable

microspheres have a d9o value from 20 pm to 150 pm.

By way of example, per injection dosages of the present compound (i.e. , therapeutically effective amounts) for local intra-articular delivery to the knee via biodegradable microspheres include, without limitation, the following: (i) 1 mg,

1.5 mg, 2 mg, 2.5 mg, 3 mg, 3.5 mg, 4 mg, 4.5 mg, 5 mg, 5.5 mg, 6 mg, 6.5 mg, 7 mg, 7.5 mg, 8 mg, 8.5 mg, 9 mg, 9.5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, or 500 mg; (ii) from 1 mg to 25 mg, from 25 mg to 50 mg, from 50 mg to 75 mg, from 75 mg to 100 mg, from 100 mg to 150 mg, from 150 mg to 200 mg, from 200 mg to 250 mg, from 250 mg to 300 mg, from 300 mg to 350 mg, from 350 mg to 400 mg, from 400 mg to 450 mg, or from 450 mg to 500 mg; or (iii) from 1 mg to 250 mg, or from 250 mg to 500 mg.

In this invention, the biodegradable microspheres can be introduced into the suitable tissue in or around one or more of the subject’s joints using any known method appropriate for the tissue in question. For example, in a preferred embodiment of the instant method where the tissue is synovial fluid in the knee joint, the method comprises intra-articularly injecting the biodegradable microspheres into the synovial fluid of one or both of the subject’s knees. In another embodiment, the instant method is performed a plurality of times (e.g., two times, three times, four times, five times, or more). In that embodiment, each subsequent time the method is performed, it is performed after a suitable period has lapsed since the preceding time the method was performed. This suitable time can be, for example, one month, two months, three months, four months, five months, six months, seven months, eight months, nine months, ten months, eleven months, one year, or longer. Microsphere-based drug products and methods of delivering them are known, at least generally (e.g., Zilretta^® (triamcinolone acetonide extended-release injectable suspension for intra- articular use (Flexion)); and Sandostatin LAR^® Depot (octreotide acetate for injectable suspension) (Novartis)).

This invention further provides an article of manufacture (kit) comprising, in separate compartments, (a) a diluent, and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm (e.g., from 20 pm to 200 pm, or from 50 pm to 150 pm); (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix (preferably having a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50 (e.g., 75:25, 80:20, 85:15, 90:10, 95:5, or 100:0)); (iii) carry a therapeutically effective amount of the present compound (preferably the present prodrug form) (e.g., from 1 mg to 500 mg of the present compound); and (iv) when present in a suitable joint-related tissue, release the compound for at least one month (and optionally release the present compound for at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, or at least twelve months).

In one embodiment of the instant kit, the microspheres further comprise polyethylene glycol (PEG). Where applicable, the embodiments described above for the instant methods are also envisioned for this article of manufacture.

In a preferred embodiment, the instant kit is supplied as a single-dose kit, and contains (i) a single dose vial of the present compound-carrying biodegradable microspheres, and (ii) a single dose vial of diluent (e.g., sterile, clear liquid solution of 0.9% w/w sodium chloride, 0.5% w/w sodium carboxymethylose, and 0.1 % w/w polysorbate-80).

Finally, this invention provides synthetic intermediates formed in the synthesis of the present active form. Specifically, this invention provides compound 6 as described in the examples that follow. This invention also provides compound 24 as described in the examples that follow. This invention further provides a method for making the active form of the present compound comprising the steps of (i) contacting compounds 6 and 24 under amide-forming conditions, and (ii) chirally resolving the resulting racemic mixture to obtain the active form of the present compound. An example of amide-forming conditions is set forth below in the examples.

This invention will be better understood by reference to the examples which follow, but those skilled in the art will readily appreciate that the specific examples detailed are only illustrative of the invention as described more fully in the claims which follow thereafter.

Examples

Example 1 - Synthetic Overview (P

1 .1 - Procedure for Preparing Compound 3

This procedure and the ones that follow in Example 1 and 2 are taken either directly or in modified form from J. Med. Chem. 2017, 60, 5933-5939. To a solution of cyclopropyl acetic acid (1 00g, 9.98 mmol) in dry CH2CI2 (20 ml_) maintained at 0 °C, and catalytic DMF (1 drop) was added. The solution was stirred and treated with oxalyl chloride (0.9 ml, 10.40 mmol) drop-wise. The resulting mixture was stirred overnight. The reaction mixture was concentrated to obtain the crude product (1 .5 g, yield >100%) which was used in the next step directly. A solution of (S)-4-benzyloxazolidin-2-one (1.32 g, 7.50 mmol) in THF (30 ml) was added n-BuLi (7.50 mmol, 3.25 ml). The reaction mixture was stirred at the temperature for 30 minutes, followed by the 2-cyclopropylacetyl chloride (1 .50 g crude, 12.65 mmol) in dry TFIF (20ML). The reaction mixture was stirred at -78 °C for 30 minutes, stirred at 0 °C for 1 .5 hrs. The reaction mixture was quenched by saturated NFUCI solution, extracted with EA (50 ml x 3). The combined organic phase was washed by brine and concentrated. The residue was further purified by flash chromatography to obtain compound 3.

Yield was 38.6%.

¹H NMR (400 MHz, CHLOROFORM-d) d 6.88 - 7.18 (m, 5H), 4.47 (tdd, J = 3.24, 7.41 , 9.51 Hz, 1 H), 3.81 - 4.10 (m, 2H), 3.09 (dd, J = 3.25, 13.38 Hz, 1 H), 2.63 - 2.76 (m, 1 H), 2.41 - 2.63 (m, 2H), 0.99 - 1 .1 1 (m, 1 H), 0.83 - 0.96 (m, 1 H), 0.21 - 0.43 (m, 2H), -0.13 - 0.14(m, 2H).

1.2 - Procedure for Preparing Compound 5

To a dry flask under nitrogen was added i-Pr2NH (0.46 mL, 3.3 mmol). To the amine was slowly added 2.5 M n-BuLi in hexanes (1.25 mL, 3.1 mmol). The LDA reagent was diluted with dry THF (20 mL). In a separate flask under N2, imide 3 (0.65 g, 25 mmol) was dissolved in THF (16 mL) and cooled to -70 °C. The LDA solution was slowly added via syringe such that the internal

temperature did not rise above -70 °C. After the addition, the mixture was stirred for 1 hour. To the resulting anion was added drop-wise compound 4 (0.66 g, 2.75 mmol) in THF (20 mL) such that the internal temperature did not rise above -70 °C. The cooling bath was allowed to expire overnight. The reaction was quenched with saturated NH4CI solution and extracted with EtOAc. The extracts were combined, washed with saturated NaCI solution, dried over MgSC , filtered, and concentrated. The residue was purified by

chromatography (gradient 0-70% EtOAc/Petroether) to give compound 5 as an oil (0.48 g, 46%).

¹H NMR (400 MHz, CHLOROFORM-d) d 7.46 - 7.59 (m, J = 8.00 Hz, 2H), 7.30 - 7.45 (m, J = 8.00 Hz, 2H), 7.20 - 7.29 (m, 4H), 6.91 - 7.14 (m, 2H), 4.58 - 4.72

(m, 1 H), 3.97 - 4.18 (m, 2H), 3.64 (dd, J = 2.63, 9.26 Hz, 1 H), 3.23 (dd, J = 8.94, 13.32 Hz, 1 H), 2.88 - 3.08 (m, 2H), 2.36 (dd, J = 9.51 , 13.38 Hz, 1 H), 1.05 - 1.14 (m, 1 H), 0.40 - 0.62 (m, 2H), 0.32 (dd, J = 4.75, 9.63 Hz, 1 H), 0.06 - 0.14 (m, 2H) 1.3 - Procedure for Preparing Compound 6

Compound 5 (0.48 g, 1.16 mmol) was dissolved in 1 :2 THF/water (30 ml_) and cooled to 0 °C. To the resulting solution was added 30% aqueous H2O2 (1.5 ml_, 15 mmol) followed by 1 M LiOH solution (2 ml_, 2 mmol). The resulting mixture was stirred at 0 °C for 2 h. The reaction was quenched via drop-wise addition of Na₂S₂0₃ (0.58 g, 4.6 mmol) in water (40 ml_). The reaction was slowly warmed to ambient temperature. The THF was removed on a rotary evaporator. The aqueous solution was washed with dichloromethane (^c2). The solution was acidified with 2 M HCI and extracted with EtOAc. The extracts were combined, washed with saturated NaCI, dried (MgSC ), filtered, and concentrated to give compound 6 as an oil (0.3 g, quantitative). LC-MS: [M+1 ]⁺

= 259.0, t_R = 2.48

1H NMR (400 MHz, METHANOL-d ) d 7.46 - 7.59 (m, J = 8.13 Hz, 2H), 7.30 - 7.46 (m, J = 8.13 Hz, 2H), 2.89 - 3.16 (m, 2H), 1.90 (dt, J = 5.88, 9.38 Hz, 1 H), 0.86 - 1.04 (m, 1 H), 0.42 - 0.59 (m, 2H), 0.20 - 0.40 (m, 1 H), 0.11 (dd, J = 3.25, 8.00 Hz, 1 H)

Example 2 - Synthetic Overview (II)

2.1 - Procedure for Preparinq Compound 21

To the 5-methyl-1 H-imidazole (1.64 g, 20 mmol) in THF was added n-BuLi (2.5 M, 8 ml_) at -40 °C, and the mixture was stirred at this temperature for 30 min. Then Mel (2.8 g, 20 mmol) was added drop-wise at -40 °C. The whole mixture was stirred and allowed to warm to room temperature and stirred overnight. It was quenched with saturated Nh CI, and extracted with EtAc. The organic layer was separated and evaporated under vacuum to give a crude product. It was purified by column to get the regioisomer (6:4), which was used directly for the next step. Yield was 50%.

¹H NMR (400 MHz, CHLOROFORM-d) d 7.38 (s, 1 H), 6.76 (s, 1 H), 3.61 (s, 1 H), 3.54 (s, 3H), 2.19 (s, 3H)

2.2 - Procedure for Preparinq Compound 22

Compound 21 (1 64g, 170 mmol) was dissolved in THF, n-BuLi (2.5 M, 88 ml_) was added drop-wise at -70 °C, and the whole mixture was stirred at this temperature for about 1 hour. Compound 7 (2.18g, 100 mmol) was dissolved in THF, and cooled to -25 °C. The lithium 1 ,5-dimethyl-1 H-imidazole was added slowly, via syringe, and stirred for 1 h, followed by warming to ambient temperature and stirring overnight. This was followed by quenching with 1.0 N hydrochloric acid, extraction with diethyl ether (3x), drying over solid sodium sulfate, and concentrating under reduced pressure to give the crude product. This was followed by purification with flash column chromatography and elution with PE:EA=4:1 to get the desired product. Yield was 30%.

¹H NMR (400 MHz, CHLOROFORM-d) d 6.95 (s, 1 H), 5.24 (br. s., 1 H), 4.68 (d, J = 5.38 Hz, 2H), 3.89 (s, 3H), 2.30 (s, 3H), 1.38 - 1.53 (m, 9H)

2.3 - Procedure for Preparing Compound 23

A mixture of compound 22 (730 mg, 2.9 mmol), TMSCN (310 mg, 4.8 mmol) and (NH4)2C03 (1 ,067 mg, 11.1 mmol) in methanol (20 ml_) and water (20ml_) is stirred at 75 °C for 72 h. The mixture is concentrated under reduced pressure to remove most of the methanol, and then extracted with EtOAc (5 x 20 ml_).

The organic phase is washed with brine, dried (Na2S04) and filtered. The combined filtrate was evaporated and purified with column chromatography eluting with CH2CI2 to MeOH = 10:1 to get the desired product. Yield was 40%. ¹H NMR (400 MHz, DMSO-d₆) d 11.09 (s, 1 H), 8.13 (br. s., 1 H), 6.73 (br. s., 1 H), 6.64 (s, 1 H), 3.81 (dd, J = 6.82, 10.44 Hz, 2H), 2.13 (s, 3H), 1.36 (s, 9H)

2.4 - Procedure for Preparing Compound 24

Compound 23 was dissolved in MeOH and treated with excess 4M HCI-dioxane at 0 °C. Upon consumption of the starting material, the reaction was

concentrated to give the amine HCI salt which was used directly in the next reaction. Yield was 100%.

2.5 - Procedure for Preparing the Present Compound

To a solution of compound 24 (88 mg, 0.4 mmol), compound 6 (104 mg, 0.4 mmol), HATU (160 mg, 0.4 mmol) in DMF was added DIPEA at 0 °C, and the reaction mixture was stirred for 6 h at room temperature. Then, water was added and extracted with EA. The combined organic layer was concentrated under vacuum. The residue was purified by chromatography on silica gel with a gradient of ChhC /MeOH = 100/1 to 10/1 to yield 78 mg of the racemic compound as a white solid. It was purified by chiral column chromatography with Heptane: EtOH = 60:40 to get the two isomers including the present compound.

LC-MS: [M+1 ]⁺ =464.2, t_R = 1.97. Figure 8 shows the H-NMR spectrum of the active form of the present compound.

Example 3 - Enzyme and Cellular Assay Methods

On-target inhibition of aggrecanases 1 and 2, without significant off-target inhibition of matrix metalloproteinases (MMPs) and TACE, is desired for an osteoarthritis drug. Inhibition of MMPs causes a side effect called

musculoskeletal syndrome with joint stiffening, nodule formation, and pain. Inhibition of TACE causes joint inflammation. 3.1 - Enzyme Assay for Inhibitory Activities on Human Adamts5 (Aggrecanase

2}

Recombinant human Adamts5 enzyme (R&D Systems) is diluted in buffer to 10 pg/ml. Buffer contains 50 mM Tris, 100 mM NaCI, 5 mM CaCh, 0.05% Brij-35, pH = 7.5. Enzyme substrate WAAG-3R is dissolved in DMSO to a

concentration of 50 mM. Twenty-five microliters of enzyme solution is added to each well of a 96-well black plate, to which 5 pi of inhibitor or DMSO control is added and incubated at room temperature for 10 minutes to allow binding. Final inhibitor concentrations range from 0.1 nM, 1 nM, 10 nM, 100 nM, 1 mM, 10 mM, 100 mM, and 1 mM. Then, 25 mI of WAAG-3R substrate is added to the enzyme-inhibitor mixture, and incubated at 37 °C. The fluorescence is read on a Molecular Device SpectraMax i3 instrument every 10-15 minutes with excitation at 340 nm and emission at 420 nm.

3.2 - Enzyme Assay for Inhibitory Activities on Human Adamts4 (Aggrecanase

H

Recombinant human Adamts4 enzyme (R&D Systems) is diluted in buffer to 10 pg/ml. Buffer contains 50 mM Tris, 50 mM NaCI, 1 mM CaCh, 0.05% Brij-35, pH = 7.5. Enzyme substrate WAAG-3R is dissolved in DMSO to a

concentration of 50 mM. Twenty-five microliters of adamts4 enzyme is added to each well of a 96-well black plate, to which 5 mI of inhibitor or DMSO control is added and incubated at room temperature for 10 minutes to allow binding. Final inhibitor concentrations range from 0.1 nM, 1 nM, 10 nM, 100 nM, 1 mM, 10 mM, 100 mM, and 1 mM. Then, 25 mI of WAAG-3R substrate is added to the enzyme-inhibitor mixture, and incubated at 37 °C. The fluorescence is read on a Molecular Device SpectraMax i3 instrument every 10-15 minutes with excitation at 340 nm and emission at 420 nm.

3.3 - Enzyme Assay for Inhibitory Activities on Human MMP-1

Make assay buffer (50 mM Tris, 10 mM CaCh, 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5) and make human recombinant MMP-1 enzyme (901 -MP, R&D Systems) stock in the assay buffer to a concentration of 50 pg/ml. The MMP-1 enzyme is activated by adding P-aminophenylmercuric acetate (Sigma, #A- 9563) to a concentration of 1 mM followed by incubation at 37 °C for 2 hours. Then, the activated MMP-1 is diluted to 1 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-1 , 5 mI tested compound dissolved in DMSO, and 25 mI substrate. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 10-15 minutes with excitation at 320 nm and emission at 405 nm.

3.4 - Enzyme Assay for Inhibitory Activities on Human MMP-2

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-2 (902-MP, R&D Systems) stock at 100 pg/ml in assay buffer. MMP-2 enzyme is activated by adding P- aminophenylmercuric acetate (Sigma, #A-9563) to a final concentration of 1 mM, followed by incubation at 37 °C for 1 hour. The activated MMP-2 enzyme is diluted to 0.2 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-2, 5 mI tested compound dissolved in DMSO, and then 25 mI ES001 substrate. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 5 minutes with excitation at 320 nm and emission at 405 nm.

3.5 - Enzyme Assay for Inhibitory Activities on Human MMP-3

The assay is conducted with a MMP-3 Fluorometric Drug Discovery Kit (BML- AK401 , Enzo Life Sciences) according to manufacturer instructions. Briefly, human recombinant MMP3 enzyme is diluted 100X fold from the manufacturer stock, and the substrate is diluted 10X fold from the manufacturer stock. In a black 96-well plate, sequentially add 10 mI MMP3 enzyme, 5 mI substrate, 30 mI assay buffer, and 5 mI of tested compound dissolved in DMSO. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 10 minutes with excitation at 328 nm and emission at 420 nm. 3.6 - Enzyme Assay for Inhibitory Activities on Human MMP-7

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-7 (907-MP, R&D Systems) stock at 100 pg/ml. MMP-7 is activated by adding P-aminophenylmercuric acetate (Sigma, #A-9563) to final concentration of 1 mM, followed by incubation at 37 °C for 1 hour. The activated MMP-7 is diluted to 0.4 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-7 enzyme, 5 mI tested compound dissolved DMSO, and then 25 mI ES001 substrate. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 5 minutes with excitation at 320 nm and emission at 405 nm.

3.7 - Enzyme Assay for Inhibitory Activities on Human MMP-8

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-8 (908-MP, R&D Systems) stock at 100 pg/ml. MMP-8 is activated by adding P-aminophenylmercuric acetate (Sigma, #A-9563) to final concentration of 1 mM, followed by incubation at 37 °C for 1 hour. The activated MMP-8 is diluted to 1 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 pi MMP-8, 5 mI of tested compound dissolved in DMSO, and then 25 mI substrate ES001. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 5 minutes with excitation at 320 nm and emission at 405 nm.

3.8 - Enzyme Assay for Inhibitory Activities on Human MMP-9

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-9 (911-MP, R&D Systems) to final concentration of 100 pg/ml. MMP-9 is activated by adding P- aminophenylmercuric acetate (Sigma, #A-9563) to final concentration of 1 mM, followed by incubation at 37 °C for 24 hours. The activated MMP-9 is diluted to 0.4 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-9, 5 mI of tested compound dissolved in DMSO, and then 25 mI substrate ES001. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 3 minutes with excitation at 320 nm and emission at 405 nm.

3.9 - Enzyme Assay for Inhibitory Activities on Human MMP-12

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-12 (917-MP, R&D Systems) by adding P-aminophenylmercuric acetate (Sigma, #A-9563) to final

concentration of 1 mM, followed by incubation at 37 °C for 24 hours. The activated MMP-12 is diluted to 0.4 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-12, 5 mI of tested compound dissolved in DMSO, and then 25 mI substrate ES001. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 5 minutes with excitation at 320 nm and emission at 405 nm.

3.10 - Enzyme Assay for Inhibitory Activities on Human MMP-13

Make assay buffer (50 mM Tris, 10 mM CaC , 150 mM NaCI, 0.05% (w/v) Brij- 35, pH = 7.5), and make human recombinant MMP-13 (511 -MM, R&D Systems) by adding P-aminophenylmercuric acetate (Sigma, #A-9563) to final

concentration of 1 mM, followed by incubation at 37 °C for 2 hours. The activated MMP-13 is diluted to 0.2 ng/mI in assay buffer, and the substrate ES001 (R&D Systems) is diluted to 20 mM in assay buffer. In a black 96-well plate, sequentially add 20 mI MMP-13, 5 mI of tested compound dissolved in DMSO, and then 25 mI substrate ES001. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 3 minutes with excitation at 320 nm and emission at 405 nm.

3.11 - Enzyme Assay for Inhibitory Activities on Human MMP-14

The assay is conducted with a MMP-14 Fluorometric Drug Discovery Kit (BML- AK417, Enzo Life Sciences) according to manufacturer instructions. Briefly, human recombinant MMP14 enzyme is diluted 100X fold from the manufacturer stock, and the substrate is diluted 10X fold from the manufacturer stock. In a black 96-well plate, sequentially add 10 mI MMP14 enzyme, 5 mI substrate, 30 mI assay buffer, and 5 mI of tested compound dissolved in DMSO. The plate is incubated at 37 °C, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument every 10 minutes with excitation at 328 nm and emission at 420 nm.

3.12 - Enzyme Assay for Inhibitory Activities on Human TACE

The assay is conducted with a TACE Inhibitor Screening Assay Kit (K366-100, Biovision) according to manufacturer instructions. Briefly, human recombinant TACE enzyme is diluted 25X fold from manufacturer stock, and the TACE substrate is diluted 12.5X fold from manufacturer stock. In a black 96-well plate, sequentially add 20 mI TACE enzyme, 5 mI tested compound dissolved in

DMSO, and 25 mI TACE substrate. The plate is incubated at 37 °C for 60 minutes, and fluorescence is read on a Molecular Device SpectraMax Gemini XS instrument with excitation at 318 nm and emission at 449 nm.

3.13 - Cellular Assay for GAG Degradation

Primary human healthy chondrocytes are expanded and made into cell aggregates by adding 200,000 cells per well into a 96-well U-bottomed deep- well plate followed by centrifugation at 300 g for 5 minutes. The condensed cell aggregates are cultured in chondrogenic differentiation medium (MesenCult™- ACF Chondrogenic Differentiation Medium, Stem Cell Technologies) for 1 week, and grown into a cartilage pellet. The chondrogenic medium is removed, and the cartilage pellets are washed with PBS. Then, 250 mI of DMEM medium (11965, ThermoFisher) was added to each cartilage pellet for overnight incubation at 37 °C. Glycosaminoglycan (GAG) is released by the cartilage pellets into the DMEM medium, and 40 mI of the conditioned medium are used for GAG quantification.

3.14 - Cellular Assay for GAG Quantification by DMMB

To make DMMB dye, first dissolve 2 g sodium formate into 980 ml water. 2 ml formic acid is then added and pH is adjusted to 3.5 as a buffer solution. In a separate tube, 16 mg dimethylmethylene blue (Santa Cruz Biotechnology) is mixed with 5 ml ethanol and added to the buffer. The volume of the DMMB dye is adjusted to 1 L. For GAG quantification, 40 mI of the sample is added to a clear 96-well plate, and 200 pi of DMMB dye is added to each well. The absorbance at 540 nm and 595 nm is read by a Molecular Device SpectraMax Plus 384 plate reader.

Example 4 - Initial Toxicity Studies

Initial toxicity studies were performed on the present compound. The following are synopses of the results of these studies. Experimental methods and data are not shown.

4.1 - Cardiac Safety

The active form of the present compound showed no inhibition on the hERG ion channel, which indicates good cardiac safety.

4.2 - Chromosomal Toxicity

An in vitro micronucleus assay on the active form of the present compound was negative, indicating no toxicity on chromosomes.

4.3 - CYP Enzyme Inhibition

The IC50s of the active form of the present compound on human CYP 1 A2,

2B6, 2C8, 2C9, 2C19, 2D6, and 3A4 are all greater than 10 micromolar, indicating lack of inhibition of these liver CYP enzymes and low risk of potential drug-drug interactions.

4.4 - Degradation by Liver Microsomes

The half-life of the active form of the present compound in the presence of liver microsomes is 40.34 minutes, which indicates fast metabolic degradation by the liver. For a long-acting depot injection in the knee, it is desirable that the systemic exposure of the drug be low. Fast metabolic degradation is a favorable property of the active form of the present compound, if administered as a long-acting (e.g., prodrug-containing microcapsule) knee injection for osteoarthritis. 4.5 - Human Plasma Stability Study

The active form of the present compound is stable in human plasma with a half- life of over 10 hours. Since the synovial fluid is an ultra-filtrate of plasma, this compound would be expected to be stable in human synovial fluid as well. This is a desirable property for a long-acting depot injection in the knee.

4.6 - Chondrocyte Growth and Matrix Production

Human healthy chondrocytes were cultured for three weeks in the presence of the active form of the present compound (10 ng/ml to 10 pg/ml) or DMSO as a negative control. DNA was quantified as an indicator of cell number.

Glycosaminoglycan (GAG) and hydroxy-proline (OHP) were major components of the cartilage matrix produced by the chondrocytes. The active form of the present compound had no negative effects on chondrocyte growth and cartilage matrix production up to 10 pg/ml.

4.7 - Synoviocyte and Chondrocyte Proliferation and Metabolism

Healthy human synoviocytes and chondrocytes were cultured in the presence of the active form of the present compound (0.1 ng/ml to 10 pg/ml) or DMSO control for 7 days. The cell proliferation and metabolism were quantified with a brief incubation of resazurin. The active form of the present compound had no negative effects on cell proliferation or metabolism.

References

Shankar, et al., U.S. Patent No. 8,859,529. Durham, et al. , International Publication No. WO 2014/066151.

Brebion, et al., International Publication No. WO 2016/102347.

Labeguere, et al., International Publication No. WO 2017/211666.

Labeguere, et al., International Publication No. WO 2017/211667.

Labeguere, et al., International Publication No. WO 2017/211668. Wang, et al. (2011 ) Intra-discal vancomycin-loaded PLGA microsphere injection for MRSA discitis: an experimental study. Arch Orthop Trauma Surg. 131 :111- 119.

Williems, et al. (2017) Safety of intradiscal injection and biocompatibility of polyester amide microspheres in a canine model predisposed to intervertebral disc degeneration. Journal of Biomedical Materials Research Part

B. 105(4):707-714.

Claims

What is claimed is:

1. A compound having the following structure:

or a pharmaceutically acceptable salt thereof.

2. A prodrug of the compound having the following structure:

or a pharmaceutically acceptable salt thereof.

3. A composition comprising the compound of claim 1 or 2 and a pharmaceutically acceptable carrier.

4. The composition of claim 3, wherein the composition is formulated for oral administration.

5. A method for treating a disorder in a subject comprising administering to the subject a therapeutically effective amount of the compound of claim 1 or 2, wherein the disorder is selected from the group consisting of osteoarthritis, synovitis, hemophilic arthropathy, rheumatoid arthritis, psoriatic arthritis, juvenile rheumatoid arthritis, gouty arthritis, septic or infectious arthritis, reactive arthritis, reflex sympathetic dystrophy, scleroderma, ankylosing spondylitis,

algodystrophy, achondroplasia, Paget’s disease, Tietze syndrome or costal chondritis, fibromyalgia, neurogenic or neuropathic arthritis, arthropathy, sarcoidosis, amylosis, cartilage injury, hydarthrosis, periodical disease, rheumatoid spondylitis, osteochondritis dissecans, hypertropic arthritis, Yersinia arthritis, pyrophosphate arthritis, an endemic form of arthritis, fibromyalgia, systemic lupus erythematosus, scleroderma, ankylosing spondylitis,

degenerative disc disease, hip dysplasia, osteochondrosis, elbow dysplasia, and joint injury caused by trauma.

6. The method of claim 5, wherein the subject is human.

7. The method of claim 5, wherein the subject is a non-human mammal.

8. A biodegradable microsphere, wherein the microsphere (i) has a diameter of from 1 pm to 500 pm; (ii) comprises a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carries the compound of claim 1 or 2; and (iv) when present in a suitable joint-related tissue, releases the compound for at least one month.

9. The biodegradable microsphere of claim 8, wherein the microsphere has a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50.

10. The biodegradable microsphere of claim 8 or 9, wherein the microsphere (i) has a diameter of from 20 pm to 200 pm; and (ii) has a lactic acid to glycolic acid molar ratio of at least 75:25.

11. The biodegradable microsphere of any of claims 8-10, wherein the microsphere further comprises polyethylene glycol (PEG).

12. A plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the compound of claim 1 or 2; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

13. The plurality of biodegradable microspheres of claim 12, wherein the microspheres further comprise polyethylene glycol (PEG).

14. The plurality of biodegradable microspheres of claim 12 or 13, wherein the microspheres (i) have a d9o value from 20 pm to 200 pm; (ii) have a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50; and (iii) carry from 1 mg to 500 mg of the compound.

15. An injectable formulation comprising (a) a pharmaceutically acceptable carrier and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the compound of claim 1 or 2; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

16. The formulation of claim 15, wherein the microspheres further comprises polyethylene glycol (PEG).

17. A method for treating a joint-related disorder in a subject comprising introducing biodegradable microspheres into suitable tissue in or around one or more of the subject’s joints, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the compound of claim 1 or 2; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.

18. The method of claim 17, wherein the microspheres further comprise polyethylene glycol (PEG).

19. The method of claim 17 or 18, wherein the subject is human.

20. The method of claim 17 or 18, wherein the subject is a non-human mammal.

21. The method of any of claims 17-20, wherein the disorder is arthritis.

22. The method of claim 21 , wherein the arthritis is osteoarthritis.

23. The method of claim 21 , wherein the arthritis is rheumatoid arthritis.

24. The method of any of claims 17-23, wherein the method comprises intra- articularly injecting the biodegradable microspheres into one or both of the subject’s knees.

25. The method of any of claims 17-24, wherein the microspheres (i) have a d9o value from 20 pm to 200 pm; (ii) have a lactic acid to glycolic acid molar ratio of from 100:0 to 50:50; and (iii) carry from 1 mg to 500 mg of the compound.

26. The method of any of claims 17-25, wherein the microspheres have an average lactic acid to glycolic acid molar ratio of at least 75:25.

27. The method of any of claims 17-26, wherein the biodegradable

microspheres have a d9o value from 20 pm to 150 pm.

28. A kit comprising, in separate compartments, (a) a diluent, and (b) a plurality of biodegradable microspheres, wherein the microspheres (i) have a d9o value from 1 pm to 500 pm; (ii) comprise a polylactic-co-glycolic acid copolymer (PLGA) matrix; (iii) carry a therapeutically effective amount of the compound of claim 1 or 2; and (iv) when present in a suitable joint-related tissue, release the compound for at least one month.