WO2015054008A1

WO2015054008A1 - 4-methylsulfonyl-2-butenenitrile and its pharmaceutical use

Info

Publication number: WO2015054008A1
Application number: PCT/US2014/058685
Authority: WO
Inventors: Joseph P. St. Laurent; Gerald S. Jones; David M. Bresse; Scott A. Goodrich
Original assignee: Olatec Industries Llc
Priority date: 2013-10-07
Filing date: 2014-10-01
Publication date: 2015-04-16
Also published as: JP2016539179A; EP3055286A4; EP3055286A1; JP6426746B2; CN105683158A

Abstract

The present invention is directed to 4-methylsulfonyl-2-butenenitrile, or a pharmaceutically acceptable salt, an isomer, or isomers thereof. The present invention is also directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier and 4-methylsulfonyl-2-butenenitrile, or a pharmaceutically acceptable salt, an isomer, or isomers thereof. The present invention is directed to a method for treating inflammation, inflammatory-related disorders, or pain, by administering 4-methylsulfonyl-2-butenenitrile, or a pharmaceutically acceptable salt or solvate thereof to a subject in need thereof.

Description

4-METHYLSULFONYL-2-BUTENENITRILE AND ITS PHARMACEUTICAL USE

FIELD OF THE INVENTION

The present invention relates to 4-methylsulfonyl-2-butenenitrile and a pharmaceutical composition comprising same. The present invention also relates to methods of using the compound for treating inflammation or inflammatory-related disorders and pain.

BACKGROUND OF THE INVENTION

Inflammation is a process by which microbes or tissue injury induce the release of cytokines and chemokines from various cell types producing increased blood vessel permeability, upregulation of endothelial receptors, and thus increased egress of various cells of the innate and adaptive immune system which enter surrounding tissue and grossly produce the classical picture of inflammation, i.e. redness, swelling, heat and pain.

Inflammation is a localized reaction of live tissue due to an injury, which may be caused by various endogenous and exogenous factors. The exogenous factors include physical, chemical, and biological factors. The endogenous factors include inflammatory mediators, antigens, and antibodies. Endogenous factors often develop under the influence of an exogenous damage. An inflammatory reaction is often followed by an altered structure and penetrability of the cellular membrane. Endogenous factors, such as mediators and antigens define the nature and type of an inflammatory reaction, especially its course in the zone of injury. In the case where tissue damage is limited to the creation of mediators, an acute form of inflammation develops. If immunologic reactions are also involved in the process, through the interaction of antigens, antibodies, and autoantigens, a long-term inflammatory process will develop. Various exogenous agents, for example, infection, injury, radiation, also provide the course of inflammatory process on a molecular level by damaging cellular membranes which initiate biochemical reactions.

Based on the physical causes, pain can be divided into three types: nociceptive, neuropathic, and mix-type.

Nociceptive pain is the term for pain that is detected by nociceptors. Nociceptors are free nerve endings that terminate just below the skin, in tendons, in joints, and in internal organs. Nociceptive pain typically responds well to treatment with opioids and NSAIDs. There are several types of nociceptive pain: somatic pain, visceral pain, and cutaneous pain. Visceral pain comes from the internal organs. Deep somatic pain is initiated by stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae and muscles, and is dull, aching, poorly localized pain. Examples include sprains and broken bones. Superficial pain is initiated by activation of nociceptors in the skin or other superficial tissue, and is sharp, well-defined and clearly located. Examples of injuries that produce superficial somatic pain include minor wounds and minor (first degree) burns. Nociceptive pain is usually short in duration and ends when the damage recovers. Examples of nociceptive pain include postoperative pain, sprains, bone fractures, burns, bumps, bruises, and inflammatory nociceptive pain. Inflammatory nociceptive pain is associated with tissue damage and the resulting inflammatory process.

Neuropathic pain is produced by damage to the neurons in the peripheral and central nervous systems and involves sensitization of these systems. Because the underlying etiologies are usually irreversible, most of neuropathic pain are chronic pain. Most people describe neuropathic pain as shooting, burning, tingling, lancinating, electric shock qualities, numbness, and persistent allodynia. The nomenclature of neuropathic pain is based on the site of initiating nervous system with the etiology; for examples, central post-stroke pain, diabetes peripheral neuropathy, post-herpetic (or post-shingles) neuralgia, terminal cancer pain, phantom limb pain.

Mix-type pain is featured by the coexistence of both nociceptive and neuropathic pain. For example, muscle pain trigger central or peripheral neuron sensitization leading to chronic low back pain, migraine, and myofacial pain.

Connective tissues are subjected to a constant barrage of stress and injury. Acute or chronic impacts and the natural progression of various degenerative diseases all produce painful inflammation in joint regions, such as the neck, back, arms, hips, ankles and feet. These afflictions are common and often debilitating.

There is a need for a composition and a method for treating inflammation, inflammatory-related disorders, and pain. The composition should be economic and easy to manufacture, and the method should be effective and have no significant side effects.

SUMMARY OF THE INVENTION

The present invention is directed to 4-methylsulfonyl-2-butenenitrile, or a

pharmaceutically acceptable salt, isomer, or isomers thereof. The present invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier and 4- methylsulfonyl-2-butenenitrile, or a pharmaceutically acceptable salt, or solvate thereof. The compound is preferably at least 90% pure (w/w).

The present invention is also directed to a method for treating inflammation and pain. The method comprises the step of administering 4-methylsulfonyl-2-butenenitrile, or a pharmaceutically acceptable salt thereof to a subject in need thereof. The pharmaceutical composition comprising the active compound can be applied by any accepted mode of administration including topical, oral, and parenteral (such as intravenous, intramuscular, subcutaneous or rectal). Topical administration and oral administration are preferred.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

"About" as used herein, refers to ± 10% of the recited value.

"Pharmaceutically acceptable salts," as used herein, are salts that retain the desired biological activity of the parent compound and do not impart undesired toxicological effects. Pharmaceutically acceptable salt forms include various crystalline polymorphs as well as the amorphous form of the different salts. The pharmaceutically acceptable salts can be formed with metal or organic counterions and include, but are not limited to, alkali metal salts such as sodium or potassium; alkaline earth metal salts such as magnesium or calcium; and ammonium or tetraalkylammonium salts, i.e., NX₄+ (wherein X is C_1-4).

"Solvates," as used herein, are addition complexes in which the compound is combined with an acceptable co-solvent in some fixed proportion.

4-Methylsulfonyl-2-butenenitrile

The inventors have isolated and identified 4-methylsulfonyl-2-butenenitrile. The compound or its pharmaceutically acceptable salt or solvate is effective for treating inflammation, inflammatory-related disorders, and pain.

4-Methylsulfonyl-2-butenenitrile has a formula weight of 145.18, and its trans structure is shown below.

4-methylsulfonyl-2-butenenitrile

4-Methylsulfonyl-2-butenenitrile can be synthesized by the addition of sodium methanesulfmate to 4-bromo-2-butenenitrile in an organic solvent containing water such as aqueous ethanol. The requisite 4-bromo-2-butenenitrile can be prepared by bromination of allyl cyanide to give 3,4-dibromobutanenitrile, followed by base-catalyzed elimination of HBr to introduce a double bond between C2 and C3, which is expected to be an

approximately 1 : 1 (e.g., between 40:60 to 60:40) mixture of E- and Z-isomers.

The present invention is directed to a method for preparing 4-methylsulfonyl-2- butenenitrile. The method comprises a step (a) of reacting 4-bromo-2-butenenitrile with sodium methanesulfmate. Any solvent or solvent mixture that is suitable for providing a homogeneous solution of the reactants is suitable. For example, a water-miscible organic solvent such as ethanol, methanol, isopropanol, acetone, tetrahydrofuran, or dioxane, containing a small amount (1-10% or 1-5%) of water is a suitable solvent for the reaction. In one embodiment, ethanol: water in a ratio of 30-40:1 is used as a solvent for the reaction.

The method may further comprise a step (i), before the above step (a), of preparing the requisite 4-bromo-2-butenenitrile by first reacting bromine (Br₂) with allyl cyanide, then adding a basic solution. In this step, allyl cyanide is first brominated in organic solvents such as petroleum ether and alcohol, and then HBr is eliminated from the molecule to form a double bond by introducing at least one equivalent of, preferably about one equivalent of, an appropriate base. In this step, an appropriate base that is compatible with the solvents in the reaction mixture is used. A preferred base is an ethanolic solution of sodium ethoxide, which can be prepared by dissolving sodium metal in ethanol. After isolation and purification of the product 4-bromo-2-butenenitrile, it can be used in step (a).

Pharmaceutical Compositions

The present invention provides pharmaceutical compositions comprising one pharmaceutically acceptable carriers and an active compound of 4-methylsulfonyl-2- butenenitrile, or a pharmaceutically acceptable salt or a solvate thereof. The pharmaceutical composition can include one of the cis or trans isomers, or both isomers either equimolar, or of different amounts. The active compound or its pharmaceutically acceptable salt or solvate in the pharmaceutical compositions in general is in an amount of about 0.01-20%, or 0.05-20%, or 0.1-20%, or 0.2-15%, or 0.5-10%, or 1-5% (w/w) for a topical formulation; about 0.1-5% for an injectable formulation, 0.1-5% for a patch formulation, about 1-90% for a tablet formulation, and 1-100% for a capsule formulation.

In one embodiment, the active compound is incorporated into any acceptable carrier, including creams, gels, lotions or other types of suspensions that can stabilize the active compound and deliver it to the affected area by topical applications. In another embodiment, the pharmaceutical composition can be in a dosage form such as tablets, capsules, granules, fine granules, powders, syrups, suppositories, injectable solutions, patches, or the like. The above pharmaceutical composition can be prepared by conventional methods.

Pharmaceutically acceptable carriers, which are inactive ingredients, can be selected by those skilled in the art using conventional criteria. Pharmaceutically acceptable carriers include, but are not limited to, non-aqueous based solutions, suspensions, emulsions, microemulsions, micellar solutions, gels, and ointments. The pharmaceutically acceptable carriers may also contain ingredients that include, but are not limited to, saline and aqueous electrolyte solutions; ionic and nonionic osmotic agents such as sodium chloride, potassium chloride, glycerol, and dextrose; pH adjusters and buffers such as salts of hydroxide, phosphate, citrate, acetate, borate; and trolamine; antioxidants such as salts, acids and/or bases of bisulfite, sulfite, metabisulfite, thiosulfite, ascorbic acid, acetyl cysteine, cysteine, glutathione, butylated hydroxyanisole, butylated hydroxytoluene, tocopherols, and ascorbyl palmitate; surfactants such as lecithin, phospholipids, including but not limited to phosphatidylcholine, phosphatidylethanolamine and phosphatidyl inositiol; poloxamers and poloxamines, polysorbates such as polysorbate 80, polysorbate 60, and polysorbate 20, polyethers such as polyethylene glycols and polypropylene glycols; polyvinyls such as polyvinyl alcohol and povidone; cellulose derivatives such as methylcellulose,

hydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose and

hydroxypropyl methylcellulose and their salts; petroleum derivatives such as mineral oil and white petrolatum; fats such as lanolin, peanut oil, palm oil, soybean oil; mono-, di-, and triglycerides; polymers of acrylic acid such as carboxypolymethylene gel, and

hydrophobically modified cross-linked acrylate copolymer; polysaccharides such as dextrans and glycosaminoglycans such as sodium hyaluronate. Such pharmaceutically acceptable carriers may be preserved against bacterial contamination using well-known preservatives, these include, but are not limited to, benzalkonium chloride, ethylenediammetetraacetic acid and its salts, benzethonium chloride, chlorhexidine, chlorobutanol, methylparaben, thimerosal, and phenylethyl alcohol, or may be formulated as a non-preserved formulation for either single or multiple use.

For example, a tablet formulation or a capsule formulation of the active compound may contain other excipients that have no bioactivity and no reaction with the active compound. Excipients of a tablet or a capsule may include fillers, binders, lubricants and glidants, disintegrators, wetting agents, and release rate modifiers. Binders promote the adhesion of particles of the formulation and are important for a tablet formulation. Examples of excipients of a tablet or a capsule include, but not limited to, carboxymethylcellulose, cellulose, ethylcellulose, hydroxypropylmethylcellulose, methylcellulose, karaya gum, starch, tragacanth gum, gelatin, magnesium stearate, titanium dioxide , poly(acrylic acid), and polyvinylpyrrolidone. For example, a tablet formulation may contain inactive ingredients such as colloidal silicon dioxide, crospovidone, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, and/or titanium dioxide. A capsule formulation may contain inactive ingredients such as gelatin, magnesium stearate, and/or titanium dioxide.

For example, a patch formulation of the active compound may comprise some inactive ingredients such as 1,3-butylene glycol, dihydroxyaluminum aminoacetate, disodium edetate, D- sorbitol, gelatin, kaolin, methylparaben, polysorbate 80, povidone, propylene glycol, propylparaben, sodium carboxymethylcellulose, sodium polyacrylate, tartaric acid, titanium dioxide, and purified water. A patch formulation may also contain skin permeability enhancer such as lactate esters (e.g., lauryl lactate) or diethylene glycol monoethyl ether.

Topical formulations including the active compound can be in a form of gel, cream, lotion, liquid, emulsion, ointment, spray, solution, and suspension. The inactive ingredients in the topical formulations for example include, but not limited to, lauryl lactate

(emollient/permeation enhancer), diethylene glycol monoethyl ether (emollient/permeation enhancer), DMSO (solubility enhancer), silicone elastomer (rheology/texture modifier), caprylic/capric triglyceride, (emollient), octisalate, (emollient UV filter), silicone fluid

(emollient/diluent), squalene (emollient), sunflower oil (emollient), and silicone dioxide (thickening agent).

In one embodiment, lauryl lactate (for example, at about 0.1-10%, or about 0.2-5%, or about 0.5-5%) is included in the topical gel formulation. Lauryl lactate is considered safe for topical administration. Lauryl lactate is qualified for human use within pharmaceutical and cosmetic products. Lauryl lactate when used in a topical formulation enhances the permeability of the compound. Preferably lauryl lactate is purified to achieve > 90%, preferably > 95% purity; the high purity mitigates the presence of hydrolytic and oxidative agents. In addition, DMSO at 0.1 -20%, or 0.5- 10% (w/w) in the formulation provides suitable solubility of the active compound.

In another embodiment, diethylene glycol monoethyl ether is included in the topical gel formulation.

Method of Use

Inflammation is a process and a state of tissue pathology resulting from activation and continuation of activity of the innate and acquired components of the immune system. The arachidonic acid cascade and cytokine production and action in cell to cell interactions are critical components of immune activation and response, which lead to inflammation.

Arachidonic acid is a component of membrane phospholipids. After it is freed from phospholipids, arachidonic acid acts as a precursor to many of the known eicosanoids including prostaglandins and leukotrienes, which are known pro-inflammatory entities.

The active compound is anti-inflammatory when applied topically in the mouse ear swelling model, in which the inflammation is induced by arachidonic acid. The active compound is effective in inhibiting pro-inflammatory mediators.

The present invention is directed to a method of treating inflammation and/or pain. 4- methylsulfonyl-2-butenenitrile, can be used as is, or it can be administered in the form of a pharmaceutical composition that additionally contains a pharmaceutically acceptable carrier. The method comprises the steps of first identifying a subject suffering from inflammation and/or pain, and administering to the subject the active compound, in an amount effective to treat inflammation and/or pain. "An effective amount," as used herein, is the amount effective to treat a disease by ameliorating the pathological condition or reducing the symptoms of the disease.

In one embodiment, the method reduces or alleviates the symptoms associated with inflammation. The present invention provides a method to treat localized manifestations of inflammation characterized by acute or chronic swelling, pain, redness, increased

temperature, or loss of function in some cases. In another embodiment, the present invention provides a method to alleviate the symptoms of pain regardless of the cause of the pain. The general term "pain" treatable by the present method includes nociceptive, neuropathic, and mix -type. The present invention reduces pain of varying severity, i.e. mild, moderate and severe pain; acute and chronic pain. The present invention is effective in treating joint pain, muscle pain, tendon pain, burn pain, and pain caused by inflammation such as rheumatoid arthritis.

In one embodiment, the present invention is useful in treating inflammation and/or pain associated in a musculoskeletal system or on the skin. The highly innervated, musculoskeletal and skin systems have a high capacity for demonstration of pain. In addition, the

musculoskeletal system has a high capacity for tissue swelling, and the skin has a high capacity for redness, swelling, and heat. In musculoskeletal and skin systems, the degree of tissue damage is frequently magnified out of proportion to the resulting inflammatory response. In the skin for example, merely firm stroking will cause release of the cytokines, IL-1 and TNF.

The present invention provides a method for treating inflammation and/or pain associated with inflammatory skeletal or muscular diseases or conditions. The method comprises the steps of identifying a subject in need thereof, and administering to the subject the active compound, in an amount effective to treat inflammation and/or pain. "The active compound," as used in this application, is intended to include 4-methylsulfonyl-2-butenenitrile and its pharmaceutically acceptable salts, isomer, or isomers thereof. The skeletal or muscular diseases or conditions include musculoskeletal sprains, musculoskeletal strains, tendonopathy, peripheral radiculopathy, osteoarthritis, joint degenerative disease, polymyalgia rheumatica, juvenile arthritis, gout, ankylosing spondylitis, psoriatic arthritis, systemic lupus erythematosus, costochondritis, tendonitis, bursitis, such as the common lateral epicondylitis (tennis elbow), medial epicondylitis (pitchers elbow) and trochanteric bursitis, temporomandibular joint syndrome, and fibromyalgia.

The present invention provides a method for treating inflammation and/or pain associated with inflammatory skin diseases such as dermatitis, psoriasis, and acne. The method comprises the steps of identifying a subject in need thereof, and administering to the subject the active compound, in an amount effective to treat inflammation and/or pain.

Skin is highly reactive to environmental stimuli and the epidermal component of keratinocytes is a very rich source of both arachidonic acid and pro-inflammatory cytokines of IL-1 and TNF. The skin dendritic cells, Langerhans cells, recognize and process antigens for further immune response of various lymphocytes and all of these cells are primarily regulated by cytokines through their specific cell surface receptors.

Dermatitis (also called eczema) is generic inflammation of the skin. Specific types of dermatitis include atopic, contact, nummular, and photo-induced.

4-Methylsulfonyl-2-butenenitrile, which is effective in inhibiting arachidonic acid induced inflammation and inhibiting pro-inflammatory mediators, is effective to treat inflammation and/or pain associated with psoriasis, acne, rosacea, and dermatitis, particularly contact dermatitis, and atopic dermatitis.

The pharmaceutical composition of the present invention can be applied by local administration and systemic administration. Local administration includes topical administration. Systemic administration includes oral, parenteral (such as intravenous, intramuscular, subcutaneous or rectal), and other systemic routes of administration. In systemic administration, the active compound first reaches plasma and then distributes into target tissues. Topical administration and oral administration are preferred routes of administration for the present invention.

Dosing of the composition can vary based on the extent of the injury and each patient's individual response. For systemic administration, plasma concentrations of the active compound delivered can vary; but are generally Ixl0^~10-lxl0^~4 moles/liter, and preferably Ixl0^"8-lxl0^~5 moles/liter.

In one embodiment, the composition is applied topically onto the affected area and rubbed into it. The composition is topically applied at least 1 or 2 times a day, or 3 to 4 times per day, depending on the medical issue and the disease pathology being chronic or acute. In general, the topical composition comprises about 0.01-20%, or 0.05-20%, or 0.1-20%, or 0.2- 15%, 0.5-10, or 1-5 % (w/w) of the active compound. For example, the topical composition comprises about 1 or 5 % (w/w) of the active compound. Depending on the size of the affected area, 0.2-85 mL, typically 0.2-10 mL, of the topical composition is applied to the individual per dose. The active compound passes through skin and is delivered to the site of discomfort.

In one embodiment, the pharmaceutical composition is administrated orally to the subject. The dosage for oral administration is generally 1-50, and preferably 1-10, or 1-5 mg/kg/day. For example, the active compound can be applied orally to an adult human at 100-800 mg/dosage, or 200-600 mg/dosage, 1-4 times a day, depends on the patient's condition. In one embodiment, the pharmaceutical composition is administrated subcutaneously to the subject. The dosage for subcutaneous administration is generally 0.3-20, and preferably 0.3-3 mg/kg/day.

Those of skill in the art will recognize that a wide variety of delivery mechanisms are also suitable for the present invention.

The present invention is useful in treating a mammal subject, such as humans, horses, and dogs. The present invention is particularly useful in treating humans.

The following examples further illustrate the present invention. These examples are intended merely to be illustrative of the present invention and are not to be construed as being limiting.

EXAMPLES

Example 1. Preparation of 4-methylsulfonyl-2-butenenitrile

(A) A solution of allyl cyanide (0.59 mole) in i-amyl alcohol (120 mL) and petroleum ether (370 mL) was treated sequentially with a solution of bromine (0.59 mole) in i-amyl alcohol (60 mL), followed by an ethanolic solution of sodium ethoxide (345 mL, 0.60 mole). When the reaction mixture had cooled to RT, solids were removed by vacuum filtration and the filtrate was concentrated under reduced pressure. The residual liquid was charged on a silica gel column (307.10 g) and eluted with hexanes-ethyl acetate (19: 1; 9:1). Combination of appropriate fractions, followed by concentration under reduced pressure gave 4-bromo-2- butenenitrile as a pale yellow liquid (47.14 g).

(B) The product from part (A) (150 mmol) was added dropwise over ~14 min to an equimolar solution of sodium methanesulfmate in ethanol (120 mL) containing water (4 mL) stirred at ~40°C. After continued heating and stirring for 6 h, the reaction mixture was concentrated under reduced pressure. The dark residual syrup was diluted with acetone, then vacuum filtered to remove sodium bromide. The filtrate was concentrated to a dark brown syrup, which was charged on a silica gel column (-255 g) that was eluted with chloroform- ethanol (19: 1). Combination of appropriate fractions, followed by concentration under reduced pressure gave a light amber-colored liquid (16.08 g). The liquid (10.48 g) was charged on a silica gel column (~310 g) that was eluted with chloroform-ethanol-hexane (66:4:30). Combination of appropriate fractions, followed by concentration under reduced pressure gave a light amber-colored liquid, which was taken up in acetone and passed through a 0.45 μηι syringe filter to remove a fine particulate. Concentration of the clear filtrate gave the expected product (9.71 g). The 1H NMR spectrum for 4-methylsulfonyl-2- butenenitrile was acquired in DMSO-d6 solution at 400MHz by Spectral Data Services, Inc. Table 1 shows the chemical shift data (ppm) of NMR results.

Table 1 . ¹H Chem ical shifts (ppm) for 4-methylsulfonyl-2-butenenitrile.

Chemical Number of

Shift (ppm) RIV ^a Protons Multiplicity Assiqnment

1.24-1.28 0. 11 impurity

1.32-1.36 0. 10 impurity

2.09 3.03 acetone

2.32-2.36 0.07 impurity

2.50 DMSO

3.2-3.3 0.23 impurity

3.5-4.2 1.22 impurities (4 signals)

4.1 -4.3 47.98 2 dd CH3SO2CH

4.3-4.4 0.39 impurity

5.2-5.3 0. 18 impurity

5.72-5.96 0.49 impurities (multiple signals)

6.08 -9.5 dm (J~16Hz) S0₂CH₂CH=CHCN (£)

1 I

6.12 -13 d (J~7Hz) S0₂CH₂CH=CHCN (Z)

6.2-6.6 0.47 impurities (multiple signals)

6.64-6.92 23.31 1 dm S0₂CH₂CH=CHCN (E,Z)

6.92-7.12 0.49 impurities (multiple signals)

H NMR: δ 3.0-3.2 (d, 3 H), 4.1-4.3 (dd, 2 H), [6.08 (dm, J~16Hz) + 6.12 (d, J~7Hz), 1 H], 6.64-6.92 (dm, 1 H).

The structure of 4-methylsulfonyl-2-butenenitrile comprises 7 protons. All protons are accounted for and occur at reasonable chemical shifts. Chemical shift assignments for the methyl and methylene protons are unequivocal. The two sets of multiplets between 6 ppm and 6.2 ppm can be distinguished by their coupling constants (J). J~16 Hz is consistent with the coupling constant expected for alkene protons in an ^-configuration, whereas J~l 1 Hz is consistent with the coupling constant expected for alkene protons in a Z-configuration.

Based on a comparison of RIV values for these signals, the E/Z ratio is -58/42. Coupling constants for the remaining alkene protons cannot be measured exactly due to the complexity of the signals between 6.6 ppm and 7 ppm. The spectrum contains some impurity/solvent peaks (RlVxotai 3.75).

Example 2. Gel Formulation 1

Table 2 exemplifies one gel formulation containing 4-methylsulfonyl-2-butenenitrile.

Table 2

Example 3. Anti-inflammatory Activity of Active Compound by Topical Application in Mice

4-Methylsulfonyl-2-butenenitrile, prepared from Example 1, was used in this experiment.

The test compound, indomethacin (positive control), and vehicle were evaluated for anti-inflammatory activity in a topical arachidonic acid-induced ear swelling model in mice.

Male ICR mice weighing 22 ± 2 g were used and randomly divided; the test compound and vehicle control had 10 mice, and indomethacin had 5 mice. Arachidonic Acid (0.5 mg in 20 μΐ of acetone :ethano 1/1 : 1) was applied topically to the anterior and posterior surfaces of the right ear of each mouse. Test substances and vehicle, as listed in Table 2 were similarly applied 30 min before and 15 min after arachidonic acid application. The thickness of the right ear and the left ear was measured and the difference calculated as an indication of the inflammation in the right ear. Ear swelling was measured by a Dyer model micrometer gauge at 60 and 90 minutes after arachidonic acid application as an index of inflammation. Percent inhibition was calculated according to the formula: Ic - It/Ic x 100, where Ic and It refers to increase of ear thickness (mm) in control and treated mice, respectively. ANOVA and Dunnett's test were employed to ascertain significant difference between vehicle control and treated groups. Significance is set at P<0.05 level. The results measured at 90 minutes after arachidonic acid application are summarized in Table 3. Table 3

The tested compound resulted in 22% inhibition in the ear swelling induced by arachidonic acid, relative to that in the vehicle-treated group. The differences between treated mice and vehicle-treated mice were determined to be statistically significant (p-value by t-test was 0.002). Example 4. Anti-inflammatory Activity of Active Compound in Mice by Oral Application (Prophetic Example)

The active compound 4-methylsulfonyl-2-butenenitrile is dissolved in a vehicle (DMSO) to 5-15 mg/mL. The test compound, dexamethasone (positive control), and vehicle are orally administered to mice and evaluated for anti-inflammatory activity in the topical arachidonic acid induced ear swelling model in mice.

Male ICR derived mice are used in this experiment. 10 mice are used for each group (active compound, positive control, and vehicle). All animals are maintained in a controlled temperature (22-24°C) and humidity (60% - 70%) environment with 12-hour light/dark cycles for at least one week prior to use.

Arachidonic acid (0.5 mg in 20 μί acetone) is applied topically onto the anterior and posterior surfaces of the right ear of test animals to induce inflammation. Test compound in vehicle (10 mL/kg) and vehicle (10 mL/kg, 50-1 0 mg/kg) are orally administered by gavage 1 hour before arachidonic acid, whereas dexamethasone is orally administered by gavage 3 hour before arachidonic acid challenge. At 60 minutes and 90 minutes after arachidonic acid induction of ear edema, the thickness of the right ear and the left ear is measured and the difference calculated as an indication of the inflammation in the right ear. Significant activity is defined as a statistically significant inhibition (p-value determined by t-test was < 0.05) in arachidonic acid induced ear swelling relative to the vehicle-treated group.

Example 5. Analgesic Activity of Active Compound by Oral Administration in Mice (Formalin Model, Prophetic Example)

Formalin test is a model of continuous pain resulting from formalin-induced tissue injury. Nociceptive and inflammatory pain is induced by injection of a dilute formalin solution into the paw, resulting in nocifensive behavior including paw flinching. The formalin model encompasses inflammatory, neurogenic, and central mechanism of pain. The early phase of pain (from 0 to about 10 minutes) is due to nociceptive mechanism and the late phase of pain (from 10-40 minutes) is due to a combination of inflammatory pain and nociceptive mechanism. Pain behavior is assessed using manual paw licking measurements. The endpoints of the study are the number of paw licking events. (Hunskaar et al., Pain, 30:103-114, 1987; Li ct ah, Molecular Pain, 6:11, 2010)

10 Mice per group are used in the study. Immediately prior to testing (at time 0), mice are restrained in a cloth and injected with 20 μΐ_^ of a 5% formalin solution,

subcutaneously into the dorsal surface of the left hind paw. Vehicle control (DMSO) and test compound 4-methylsulfonyl-2-butenenitrile (in DMSO) are administered by oral gavage with a volume of 5 mL/kg to mice. The amounts of test compound are 100 or 500 mg/kg per dose.

Positive control morphine in saline is administered by subcutaneous injection at 8 mg kg to mice, immediately before formalin injection and testing at time zero.

Following formalin injection , animals are placed in individual cages, and manually observed for 60 minutes. The licking events are recorded in five minute intervals continuously for a total of 60 minutes.

The number of licking events at different time points post formalin injection of vehicle control, morphine-treated, and test compound-treated mice are plotted in 5 minute intervals.

The numbers of licking events per minute are calculated between 0-10 minutes and 10-40 minutes for vehicle, positive control, and test compound. A statistically significant reduction of licking event per minute is an indication that the test compound is effective in treating acute nociceptive pain (early phase) or inflammatory nociceptive pain (late phase).

Example 6. Analgesic Activity of Active Compound by Topical Administration in Mice (Formalin Model, Prophetic Example) The animals and the treatment protocol are similar to those described in Example 5, except the following.

The test compound 4-methylsulfonyl-2-butenenitrile (375 mM in vehicle, n=10) and vehicle control (acetone :ethanol 1 :1, n=10) are administered topically by submerging the mouse left hind paw in the respective solution for about 30 seconds. The paw is then withdrawn and wiped with tissue to avoid excess dermal drying.

Positive control morphine is administered by subcutaneous injection at 8 mg/kg in saline (n=10).

Morphine is subcutaneous ly administered once 15 minutes before formalin injection. The test compounds and vehicle control are topically administered twice (BID), at 60 minutes before formalin injection.

Following formalin injection , animals are placed in individual cages, and manually observed for 60 minutes. The licking events are recorded in five minute intervals continuously for a total of 40 minutes.

The number of licking events at different time points post formalin injection of vehicle control, morphine-treated, and test compound-treated mice are determined.

The numbers of licking events per minute are calculated between 0-10 minutes and 10-40 minutes for vehicle, positive control, and test compound. A two-sample t-test is done to compare the vehicle group with the test compound group. Significance is set at P<0.05 level.

Example 7. Analgesic Activity of Active Compound in Chronic Constriction Injury Model (Prophetic Example)

Peripheral nerve lesions may generate a syndrome comprising, in addition to spontaneous pain, exaggerated responses to light touch (tactile allodynia). Chronic constriction injury model is a neuropathic pain model.

Male Sprague Dawley rats are used. Under pentobarbital (50 mg/kg, 5 ml/kg, i.p.) anesthesia, the sciatic nerve is exposed at mid-thigh level. Four ligatures (4-0 chromic gut), about 1 mm apart, are loosely tied around the nerve. The animals are then housed individually in cages with soft bedding for 7 days before testing. Constriction of the sciatic nerve produces nerve injury and unilateral neuropathic pain.

On the day of experiments, the animals have no access to food overnight before testing. The rats are placed under inverted plexiglass cages on a wire mesh rack and allowed to acclimate for 20 to 30 minutes. Mechanic allodynia is evaluated by the Chaplan up/down method using von Frey filaments to the plantar surface of the left hind paw. See Chaplan, et al. J. Neuroscience Methods, 53: 55-63, 1994.

Rats are pre-selected for experimentation only if the pain threshold 7-14 days after nerve ligation (pre-treatment) is reduced by 10 grams of force relative to the response of the individual paw before nerve ligation (pre-ligation), namely, with clear presence of allodynia.

The active compound 4-methylsulfonyl-2-butenenitrile is prepared in the gel formulation according to Example 2.

Active compound in gel formulation (1 or 5%, topical administration), active compound in DMSO (500 mg/kg, oral administration), morphine (positive control, subcutaneous, 8 mg/kg in saline), topical vehicle (gel formulation without the active compound), and oral vehicle (DMSO) are evaluated.

Test substance or vehicle is either administered orally or topically to the plantar surface of the left hind paw. The mechanical allodynia test is performed 30 min before (pre- treatment) and 1 and 3 hours after a single dose of test substance or vehicle (post treatment). Paw withdraw thresholds of control and tested compound are measured.

Example 8. Treatment of Knee Pain by Topical Administration (Prophetic Example)

Objectives: To investigate the efficacy of the active compound in a topical gel formulation in human patients with mild to severe knee pain associated with osteoarthritis following temporary cessation of standard NSAID therapy. The focus of this study is on the symptoms caused by painful arthritis. The clinical trial is utilizing osteoarthritis of the knee as a well-established paradigm for other musculoskeletal disorders.

Topical Formulation: The gel formulations containing the active compound 4- methylsulfonyl-2-butenenitrile at 1% and 5% (Example 2) are used in this example. Placebo contains the same gel without the active compound.

Methodology: A randomized, double-blind, placebo controlled, parallel treatment multicenter clinical activity study.

Patients with painful osteoarthritis of the knee, controlled by a stable dose of standard NSAID therapy for at least 2 months, discontinue use of the NSAIDs for a 7-day washout period. Patients are then randomized in a 1 : 1 : 1 ratio (1% active gel, 5% active gel, placebo). A total of up to 150 patients are enrolled.

The active gel or placebo is applied to the affected knee 3 times a day for 12 weeks for a total of 252 treatments given every 4 - 6 hours while awake.

Patients are treated for 12 weeks and followed up for a further 4 weeks. NSAIDs may be restarted after the Week 12 visit.

Criteria for Evaluation:

Safety:

Adverse Events (AEs) throughout the study.

• Physical examination at enrollment (-7 days, start of NSAID washout period), Baseline (Day 1, start of treatment), Week 12 and Week 16.

Vital signs at enrollment (-7 days, start of NSAID washout period), Baseline (Day 1, start of treatment) and Weeks 2, 4, 6, 12 and 16.

Clinical laboratory measurements at Baseline (Day 1), Week 4, 8, 12 and 16.

Clinical Activity:

The primary clinical activity parameters are the measurement of pain in the target joint, as quantified by the Visual Analog Scale (VAS) and the Western Ontario and

McMaster University (WOMAC) Index pain subscale. The effect of treatment on swelling, tenderness and inflammation of the knee is recorded, also the time to reduction or eradication of pain after treatment is recorded.

Study Endpoints:

The primary clinical activity endpoint is:

Change from Baseline (Day 1) to Week 12 in WOMAC functional disability index pain subscale (Scale 0 - 20)

The secondary clinical activity endpoints are:

• Change from Baseline (Day 1) to Week 12 in WOMAC functional disability index subscales:

Stiffness (Scale 0 - 8).

Physical function (Scale 0 - 68). • Change from Baseline (Day 1) to Week 12 in VAS pain score (0 - 100). Change from Baseline (Day 1) to Week 2 in VAS pain score (0 - 100).

Change in investigator evaluation of swelling, tenderness and inflammation between Baseline (Day 1) and Weeks 4 and 12 after the first application on Day 1.

· Time to reduction or eradication of pain subsequent to each topical application of active gel or placebo gel.

Use of rescue medication (APAP).

Example 9. Treatment of Knee Pain by Oral Administration (Prophetic Example) The design and protocols of this experiment are similar to those described in Example

9, except the active compounds and placebo are applied by an oral route.

Oral Formulation: Tablet formulations containing 10, 100, or 1000 mg of the active compound 4-methylsulfonyl-2-butenenitrile are used in this example. Placebo has the same tablet formulation without the active compound.

Methodology:

Patients are then randomized in a 1 :1 :1 :1 ratio (10 mg: 100 mg: 1000 mg: placebo). A total of up to 200 patients are enrolled.

The active tablet or placebo is administered orally to each patient two times a day for

12 weeks for a total of 168 treatments given every 12 hours while awake. Patients are treated for 12 weeks and followed up for a further 4 weeks.

Criteria for evaluation are the same as those described in Example 9. It is to be understood that the foregoing describes preferred embodiments of the present invention and that modifications may be made therein without departing from the scope of the present invention as set forth in the claims.

Claims

WHAT IS CLAIMED IS:

1. A compound of 4-methylsulfonyl-2-butenenitrile or a pharmaceutically acceptable salt thereof.

2. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and the compound of Claim 1 , or a pharmaceutically acceptable salt thereof.

3. The pharmaceutical composition according to Claim 1 , wherein the compound has at least 90% (w/w) purity, and the composition is in a topical form of gels, creams, lotions, ointments, solutions, suspensions, sprays, or patches.

4. The pharmaceutical composition according to Claim 3, wherein the pharmaceutically acceptable carrier is an emollient selected from the group consisting of: lauryl lactate, diethylene glycol monoethyl ether, caprylic/capric triglyceride, octisalate, silicone fluid, squalene, and sunflower oil.

5. The pharmaceutical composition according to Claim 2, wherein the pharmaceutically acceptable carrier is diethylene glycol monoethyl ether.

6. The pharmaceutical composition according to Claim 5, further comprising acrylates/ClO- 30 alkyl and tris(2-hydroxyethyl)amine.

7. The pharmaceutical composition according to Claim 2, wherein the compound has at least 90% (w/w) purity, and the composition is in an oral form of tablets, capsules, granules, powders, or syrups.

8. A method of treating inflammation or pain, comprising the steps of:

identifying a subject suffering from inflammation or pain, and

administering to the subject the compound of Claim 1, or a pharmaceutically acceptable salt thereof in an amount effective to treat inflammation or pain.

9. The method according to Claim 8, wherein said method reduces or alleviates the symptoms of localized manifestations of inflammation characterized by acute or chronic swelling, pain, or redness.

10. The method according to Claim 8, wherein said compound is administered by local administration or systemic administration.

11. The method according to Claim 10, wherein said compound is administered by topical administration or oral administration.

12. The method according to Claim 8, wherein said inflammation and/or pain is associated with a skeletal or muscular disease or condition selected from the group consisting of:

musculoskeletal sprains, musculoskeletal strains, tendonopathy, peripheral radiculopathy, osteoarthritis, degenerative joint disease, juvenile arthritis, gout, ankylosing spondylitis, psoriatic arthritis, system lupus erythematosus, costochondritis, tendonitis, bursitis, temporomandibular joint syndrome, and fibromyalgia.

13. The method according to Claim 8, wherein said inflammation and/or pain is associated with joints, ligaments, tendons, bone, muscles, or fascia.

14. The method according to Claim 8, wherein said inflammation and/or pain is associated with an inflammatory skin disease or disorder of dermatitis or psoriasis.

15. A process for preparing 4-methylsulfonyl-2-butenenitrile, comprising the step of: reacting 4-bromo-2-butenenitrile with sodium methanesulfmate.

16. The process according to Claim 16, further comprises the steps of preparing 4-bromo- 2-butenenitrile by:

reacting bromine Br₂ with allyl cyanide, and

adding a basic solution.