(s,s)-(3-o-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene and its analogues for the treatment of chronic pain

Abstract

The present invention relates to a compound of formula (I) or its pharmaceutically acceptable salt. The compound of formula (I) is particularly useful in the treatment or prevention of pain, inflammation or autoimmune disease.

Description

[0001] 1

[0002] (S,S)-(3-O-(Propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene and its analogues for the treatment of chronic pain

[0003] The present invention relates to a compound of formula (I) or its pharmaceutically acceptable salt. The compound of formula (I) is particularly useful in the treatment or prevention of pain, inflammation or autoimmune disease.

[0004] Pain is a multifaceted or multidimensional, experiential response to a variety of stimulus conditions. Pain is defined by the International Association for the Study of Pain (IASP) as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage".

[0005] Pain in animals is frequently the result of nociception, i.e., activity in the nervous system that results from the stimulation of nociceptors. Neuropathic pain differs from nociceptive pain in that it involves damage to the nerve resulting in the sensation of pain. In central pain, the pain is generated in the brain from some form of lesion. Occasionally pain may be psychogenic, i.e., caused by mental illness.

[0006] Pain can be acute or chronic. Acute pain is usually caused by soft tissue damage, infection and / or inflammation among other causes. Acute pain serves to alert after an injury or malfunction of the body. Chronic pain may have no apparent cause or may be caused by a developing illness or imbalance. Chronic pain is defined as the disease of pain; its origin, duration, intensity and specific symptoms may vary.

[0007] The experience of physiological pain can be grouped according to the source and related nociceptors. Cutaneous pain is caused by injury to the skin or superficial tissues. Cutaneous nociceptors terminate just below the skin, and due to the high concentration of nerve endings, produce a well-defined, localised pain of short duration. Examples of injuries that produce cutaneous pain include paper cuts, minor cuts, minor (first-degree) burns and lacerations. Somatic pain originates from ligaments, tendons, bones, blood vessels and nerves. It is detected with somatic nociceptors. The scarcity of pain receptors in these areas produces a dull, poorly-localised pain of longer duration than cutaneous pain; examples include sprains and broken bones. Myofascial pain is usually caused by trigger points in muscles, tendons and fascia and may be local or referred. Visceral pain originates from the body's viscera or organs. Visceral nociceptors 2 are located within body organs and internal cavities. The even greater scarcity of nociceptors in these areas produces pain that is usually more aching and for longer duration than somatic pain. Visceral pain is extremely difficult to localise, and several injuries to visceral tissue exhibit "referred" pain, where the sensation is localised to an area completely unrelated to the site of injury. Phantom limb pain, a type of referred pain, is the sensation of pain from a limb that has been lost or for which a person no longer receives physical signals. Neuropathic pain may occur as a result of injury or disease to the nerve tissue itself. This can disrupt the ability of the sensory nerves to transmit correct information to the thalamus, and hence the brain interprets painful stimuli even though there is no obvious psychological cause for the pain.

[0008] Acute pain is usually treated simultaneously with pharmaceuticals or appropriate techniques for removing the cause and pharmaceuticals or appropriate techniques for controlling the pain sensation, commonly analgesics.

[0009] Analgesics fall into three categories: opioid (narcotic) analgesics, non-opioid analgesics and adjuvant analgesics. Opioid analgesics are powerful analgesics that are chemically related to morphine. However, opioids have many side effects, which may be more likely to occur in people with certain disorders: kidney failure, a liver disorder, chronic obstructive pulmonary disease (CORD), dementia or another brain disorder. Drowsiness, constipation, nausea, vomiting and itching are common when opioids are started. Apart from morphine, opioid analgesics known at the time of writing include codeine, fentanyl, hydrocodone, hydromorphone, levorphanol, meperidine, methadone, oxycodone, oxymorphone, pentazocine and propoxyphene.

[0010] A variety of non-opioid analgesics are also available at the time of writing. They are often effective for mild to moderate pain. Most non-opioid analgesics are classified as non-steroidal anti-inflammatory drugs (NSAIDs). An example of an analgesic that is not an NSAID is acetaminophen, which is commonly known as paracetamol. Acetaminophen has substantially no anti-inflammatory properties.

[0011] NSAIDs are used to treat mild to moderate pain and may be combined with opioids to treat moderate to severe pain. NSAIDs not only relieve pain, but they also reduce the inflammation that often accompanies and worsens pain. Although widely used, NSAIDs can also have side effects, sometimes serious ones, including problems in the digestive tract, bleeding problems, problems related to retaining fluids and increased risk of heart and blood vessel disorders. Current NSAIDs include aspirin, ibuprofen, ketoprofen, naproxen, cox-2 inhibitors such as celecoxib, choline magnesium trisalicylate, diflunisal, salsalate, diclofenac, etodolac, fenoprofen, flurbiprofen, indomethacin, ketorolac, meclofenamate, mefenamic acid, meloxicam, nabumetone, oxaprozin, piroxicam, sulindac and tolmetin.

[0012] Adjuvant analgesics include antidepressants such, for example, as imipramine, amitriptyline, bupropion, desipramine, fluoxetine and venlafaxine; anticonvulsants (such as carbamazepine, gabapentin and 3 pregabalin) and oral and topical local anaesthetics.

[0013] In the treatment of chronic pain, the "Three-Step Analgesic Ladder" developed by the World Health Organization is often used. For mild pain, acetaminophen, aspirin or other NSAIDs may be employed. For mild to moderate pain, weak opioids such as codeine and dihydrocodeine are employed in combination with acetaminophen, aspirin or other NSAIDs. In the case of moderate to severe pain, strong opioids such as morphine, diamorphine, or fentanyl, hydromorphone, methadone, oxycodone or phenazocine may be administered in combination with acetaminophen, aspirin or other NSAIDs.

[0014] Document WO 2009 / 109850 provides compounds for use in the treatment or prophylaxis of pain, including acute and chronic pain (e.g., nociceptive pain, neuropathic pain, headaches, migraine), represented by general formula: in which the dotted line represents a single or a double bond; and Rs and Rs' are independently -H, -OH or -ORs, where Rs is a linear or branched C1-C4 alkyl; X is -O-, -CH2O-, -CH2CH2O-, -CH(CH3)CH2O- or - CH2CH(CH3)O-; Z is -CH2CH2O-, -CH(CH3)CH2O- or -CH2CH(CH3)O-; m is an integer of 0 or 1 ; and n is an integer of 0-50. Provided compounds are also effective for reducing inflammation and may be used alone or in combination with other analgesics.

[0015] Prior art documents US 7754’771 , WO 2011 / 030205, US 2011 / 0086910, and WO 2013 / 084238 disclose 2-N(3-O-(propan-2-ol)-1-propyl-4-hydroxybenzene)-3-phenylpropylamide for treatment or prophylaxis of pain and inflammation.

[0016] Document WO 2020 / 152226 discloses a polymorphic form of (S,S)-2-N(3-O-(propan-2-ol)-1-propyl-4- hydroxybenzene)-3-phenylpropylamide, which is particularly useful in the treatment or prophylaxis of pain, inflammation and / or autoimmunity (autoimmune disease). The polymorph is extensively characterized by methods such as X-ray, DSC and / or Raman spectroscopy. 4

[0017] Document \N0 2013 / 192286 discloses certain compounds, including (S)-2-(2-amino-3- phenylpropoxy)ethanol.

[0018] The currently available treatments for neuropathic pain have only low to moderate efficacy, and many patients are left without significant pain relief. The lack of adequate pain relief for millions of people with neuropathic pain, as well as for those with other types of pain, represents a great unmet medical need.

[0019] It was accordingly an object of the present invention to provide highly active compounds for the treatment of neuropathic pain, as well as the treatment or prevention of inflammation and / or treatment or prevention of autoimmune disease.

[0020] This object is addressed by the embodiments described herein and as characterized in the claims.

[0021] Accordingly, the present inventors have shown that (S,S)-2-N(3-O-(propan-2-ol)-1-propyl-4- hydroxybenzene)-3-phenylpropylamide is metabolized upon administration to a human subject to, among others, (S,S)-(3-O-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene (see Figure 1), which surprisingly shows the activity exceeding that of its parent compound in the treatment of pain (in particular neuropathic pain), inflammation and autoimmune disease (as demonstrated in Example 2 hereinbelow, wherein the activity of the compound of the invention in the von Frey test is higher and lasts longer than that of the compound of the prior art - see Figure 3). As it is apparent to the skilled person, the observations of the present inventors regarding the activity of (S,S)-(3-0-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene which mimics the activity of (S,S)-2-N(3-O-(propan-2-ol)-1-propyl-4-hydroxybenzene)-3- phenylpropylamide can be plausibly generalized to analogous metabolites of the compound disclosed in WO 2009 / 109850.

[0022] Thus, the present invention is based, at least in part, on a surprising discovery of the present inventors that (S,S)-(3-0-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene, which is a metabolite of (S,S)-2-N(3- 0-(propan-2-ol)-1-propyl-4-hydroxybenzene)-3-phenylpropylamide, mimics its activity against pain, inflammation and autoimmune disease.

[0023] The present invention will be summarized in the following embodiments.

[0024] In a first embodiment, the present invention relates to a a compound of formula (I):

[0025]

[0026] (I) or a pharmaceutically acceptable salt thereof, wherein

[0027] X is selected from -0-, -CH2O-, -CH2CH2O-, -CH(CH3)CH2O-, and -CH2C(CH3)O-;

[0028] Znis selected from -(CH2CH2O)n-, -(CH(CH3)CH2O)n-, and -(CH2C(CH3)O)n-; n is an integer from 1 to 50; and

[0029] R is selected from -H, and -OH.

[0030] In a second embodiment, the present invention relates to a pharmaceutical composition comprising the compound of the present invention and at least one pharmaceutically acceptable carrier.

[0031] In a third embodiment of the present invention, the present invention relates to the compound of the present invention or the pharmaceutical composition of the present invention for use as a medicament.

[0032] In a fourth embodiment of the present invention, the present invention relates to the compound of the present invention or the pharmaceutical composition of the present invention for use in the treatment or prevention of a disease selected from pain, inflammation and autoimmune disease.

[0033] In a fifth embodiment of the present invention, the present invention relates to use of the compound of the present invention in the manufacture of a medicament for the treatment or prevention of a disease selected from pain, inflammation and autoimmune disease.

[0034] In a sixth embodiment of the present invention, the present invention relates to a method of treatment of a disease selected from pain, inflammation and autoimmune disease, the method comprising the step of administering the compound of the present invention to a subject in need thereof. It is to be understood that a therapeutically effective amount of the compound of the invention is to be administered.

[0035] The invention will be further illustrated in the following Figures. 6

[0036] Fig. 1 presents the metabolization pathways of 2-N(3-O-(propan-2-ol)-1-propyl-4-hydroxybenzene)-3- phenylpropylamide (configuration of chiral centers not shown), which lead, among others, to the formation of metabolite M25, being (3-0-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene (configuration of chiral centers not shown) and characterized by molecular weight of m / z = 226. The metabolites appearing in the body have been established in a Mass Balance study. NRD135S.E1 glucuronide m / z 534= M1-M2; Hydroxylated NRD135S.E1 m / z 374= M3-M6; Hydroxylated glucuronide m / z 550= M7-M9; Methoxylated glucuronide m / z 564= M12-M13; Methoxylated NRD135S.E1 m / z 388=M17; Cleavage amine glucuronide m / z 402= M23-M24; Cleavage amine m / z 226=M25; Sulphated clavage amine m / z 306= M26-M27; Cleavage methoxylated glucuronide m / z 432=M28-M29; Cleavage hydroxylated glucuronide m / z 418= M30- M31 ; Cleavage acetate glucuronide m / z 444=M33; PPA (phenylpropionic acid) m / z 151 / 149=M34; Cleavage acetate m / z 268=M356.

[0037] Fig. 2 shows1H-13C HSQC (part 1) and1H-13C HMBC spectra of the compound M25-1 .

[0038] Fig. 3 shows the results of Von Frey (VF) test. The bars, from left to right, represent the following animal groups: 1. Vehicle IV (Group 1); 2. Gabapentin IP 150 mg / kg (Group 2); 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group 3); 4. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group 4); 5. M25 IV bolus 0.685 mg. kg + Iv infusion 16.9 mg / h / kg (Group 5); 6. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 7. NRD PO 80 mg / kg (Group 7).

[0039] Fig. 4 shows mean group body weight. The bars, from left to right, represent the following animal groups: 1. Vehicle IV (Group 1); 2. Gabapentin IP 150 mg / kg (Group 2); 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group 3); 4. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group

[0040] 4); 5. M25 IV bolus 0.685 mg.kg + Iv infusion 16.9 mg / h / kg (Group 5); 6. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 7. NRD PO 80 mg / kg (Group 7).

[0041] Fig. 5 shows A. Von Frey force required for PAW withdrawal The groups of bars, from left to right, represent the following animal groups: 1 . Vehicle IV (Group 1); 2. Gabapentin IP 150 mg / kg (Group

[0042] 2); 3. NRD PO 80 mg / kg (Group 7), 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group

[0043] 3); 5. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 6. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group 4); 7. M25 IV bolus 0.685 mg. kg + Iv infusion 16.9 mg / h / kg (Group 5). B. Von Frey force required for Paw withdrawal - net response (AUEC) with vehicle 7 response subtracted (Response integrals (AUEC) were obtained for each group by calculating the average ± SD area under the individual effect-time curves using the linear trapezoidal rule. The net effect was calculated by subtracting the average vehicle integral from the average group integral. The error estimation for the resulting difference (error bars) was calculated by RMS averaging of the respective absolute standard deviations.) The bars, from left to right, represent the following animal groups: 2. Gabapentin IP 150 mg / kg (Group 2); 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group 3); 4. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group 4); 5. M25 IV bolus 0.685 mg. kg + Iv infusion 16.9 mg / h / kg (Group 5); 6. M25 IV bolus 0.027 mg / kg + iv infusion 0.676 mg / h / kg (Group 6); 7. NRD PO 80 mg / kg (Group 7). C. Comparison of effect (Von Frey)-time courses of M25 (mid-dose) to Gabapentin; D. Comparison of effect (Von Frey)-time courses of M25 (mid-dose) to NRD 80 mg / kg PO.

[0044] Fig. 6 shows cold plate test. A. All individual data is shown. The groups of bars, from left to right, represent the following animal groups: 1. Vehicle IV (Group 1); 2. Gabapentin IP 150 mg / kg (Group 2); 3. NRD PO 80 mg / kg (Group 7), 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group 3); 5. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 6. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group 4); 7. M25 IV bolus 0.685 mg.kg + iv infusion 16.9 mg / h / kg (Group 5). B. Data shown by test day. The bars, from left to right, represent the following animal groups: 1. Vehicle IV (Group 1); 2. Gabapentin IP 150 mg / kg (Group 2); 4. NRD IV bolus 1.65 mg / kg + IV infusion 8.16 mg / h / kg (Group 3); 4. M25 IV bolus 0.137 mg / kg + IV infusion 3.38 mg / h / kg (Group 4); 5. M25 IV bolus 0.685 mg.kg + Iv infusion 16.9 mg / h / kg (Group 5); 6. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 7. NRD PO 80 mg / kg (Group 7). C data shown as net response (AUEC) with vehicle response subtracted (Response integrals (AUEC) were obtained for each group by calculating the average ± SD area under the individual effect-time curves using the linear trapezoidal rule. The net effect was calculated by subtracting the average vehicle integral from the average group integral. The error estimation for the resulting difference (error bars) was calculated by RMS averaging of the respective absolute standard deviations.) The bars, from left to right, represent the following animal groups: 2. Gabapentin IP 150 mg / kg (Group 2); 4. NRD IV bolus 1 .65 mg / kg + iv infusion 8.16 mg / h / kg (Group 3); 4. M25 IV bolus 0.137 mg / kg + iv infusion 3.38 mg / h / kg (Group 4); 5. M25 IV bolus 0.685 mg.kg + Iv infusion 16.9 mg / h / kg (Group 5); 6. M25 IV bolus 0.027 mg / kg + IV infusion 0.676 mg / h / kg (Group 6); 7. NRD PO 80 mg / kg (Group 7). D Comparison of Effect (Cold Plate)-Time Courses of M25 (mid-dose) to Gabapentin; E Comparison of Effect (Cold Plate)-Time Courses of M25 (mid-dose) to NRD 80 mg / kg PO. 8

[0045] Fig. 7 shows A NRD and M25 Concentration-Time Profiles following NRD Administrations, B M25 Concentration-Time Profiles following M25 Administrations, and C Relationship of Administered M25 Dose and Resulting Exposure (AUC0-24h).

[0046] Fig. 8 shows PKPD Relationship with M25 Exposure (AUC0-24h) with Effects (Von Frey).

[0047] As mentioned above, the present invention relates to a compound of formula (I): or a pharmaceutically acceptable salt thereof.

[0048] In formula (I), X is selected from -O-, -CH2O-, -CH2CH2O-, -CH(CH3)CH2O-, and -CH2C(CH3)O-. It is to be understood that X is a bivalent moiety, which is connected to a Z moiety through 0 atom of X. Accordingly and preferably, X is connected to Z through its 0 atom.

[0049] Preferably, X is -CH2O- or -CH2CH2O-. More preferably, X is -CH2O-.

[0050] In formula (I), Znis selected from -(CH2CH2O)n-, -(CH(CH3)CH2O)n-, and -(CH2C(CH3)O)n- and n is an integer from 1 to 50. It is to be understood that Znis a bivalent moiety connected to X through its C atom and connected to H through its 0 atom.

[0051] It is apparent to the skilled person that multiple copies of the Z moiety may be present, namely Z copies.

[0052] It is to be understood that each Z moiety in Znis the same moiety.

[0053] It is preferred that Znis -(CH2C(CH3)O)n- Particularly preferred is a moiety wherein the configuration of each chiral carbon atom is as in the following formula:

[0054] In Zn, n may be an integer selected from 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, and 50. It is preferred that n is an integer from 1 to 10, more preferably an integer from 1 to 5, even more preferably n is 1. Accordingly, n may be selected from 1 , 2, 3, 4, 5, 6, 7, 8, 9 and 10, preferably n may be selected from 1 , 2, 3, 4 and 5, more preferably n is 1.

[0055] In a preferred embodiment wherein n is 1, Znis selected from -CH2CH2O-, -CH(CHs)CH2O-, and - CH2C(CH3)O-, preferably Znis -CH2C(CH3)O- Given the preferred configuration of the chiral carbon atom in the most preferred embodiment of Znmoiety, preferably Zn is a moiety of formula:

[0056] It is to be understood that in certain embodiments of the present invention Znis a polyglycol moiety, and as it is apparent to the skilled person, due to inevitable certain degree of inhomogeneity introduced in the synthesis of such polyglycol moiety, molecules that include Znmoieties characterized by different n parameter may be present in a single preparation. Thus, in particular for n > 10, provided n may refer to average n characterizing the Znmoiety (or an integer approximating said average n parameter), while Znmoieties characterize not only by this particular n, and other repetition numbers, in particular by n+1 , n+2, n+3, n-1, n-2, and n-3, may also be present.

[0057] In formula (I), R is selected from -H, -OH and -0( C1-4alkyl). Particularly suitable C1-4alkyl moieties are methyl or ethyl, preferably methyl.

[0058] Preferably, R is selected from -H, and -OH. More preferably, R is -OH.

[0059] It is to be understood that the benzene ring in formula (I), (in particular if R is not H), can be substituted at ortho, meta or para positions. Preferably, (in particular if R is not H), the benzene ring in formula (I) is substituted at para positions. 10

[0060] Thus, preferably, the compound of formula (I) is a compound of formula (la): or a pharmaceutically acceptable salt thereof, wherein X, Znand R are as defined for formula (I).

[0061] The configuration of the chiral center at the carbon atom that carries -NH2 group in formula (I) or formula (lb) is preferably as in formula (lc):

[0062] Thus, preferably the compound of formula (I) or the compound of formula (lb) is a compound of formula (lc), as defined hereinabove, or a pharmaceutically acceptable salt thereof. In formula (lc), X, Znand R are as defined for formula (I).

[0063] Preferably, in formula (I) X is -CH2O-, Znis -CH2C(CH3)O- and R is -OH. Thus, the compound of formula (I) may be a compound of formula (Id): 11 or a pharmaceutically acceptable salt thereof. Preferably, the compound of formula (Id) is a compound of formula (le): or a pharmaceutically acceptable salt thereof.

[0064] Accordingly, particularly preferred compound of formula (I) is a compound of formula (le), i.e. (S,S)-(3-O- (propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene. It is preferred that said compound is substantially free of other stereoisomeric forms of this compound. A representative substantially pure enantiomer comprises greater than 90% by weight of one enantiomer of the compound and less than 10% by weight of the other stereoisomeric forms of the compound, preferably greater than 95% by weight of one enantiomer of the compound and less than 5% by weight of the other stereoisomeric forms of the compound, even more preferably greater than 98% by weight of one enantiomeric form of the compound and less than 2% by weight of the other stereoisomeric forms of the compound. The term “other stereoisomeric forms” typically refers to the (S,R), (R,S) and (R,R) enantiomeric or diastereomeric forms of the compound (S,S)-(3-O-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene.

[0065] The compound of formula (le) can be prepared as demonstrated in, or per analogy to, the experimental protocol shown in Example 1. It is apparent to the skilled person that the compound of formula (I) can be prepared per analogy to the specific synthetic protocol demonstrated in Example 1.

[0066] The scope of the invention embraces all pharmaceutically acceptable salt forms of the compounds of formula (I) which may be formed, e.g., by protonation of an atom carrying an electron lone pair which is susceptible to protonation, such as an amino group, with an inorganic or organic acid, or as a salt of an acid group (such as a carboxylic acid group) with a physiologically acceptable cation. Exemplary base addition salts comprise, for example: alkali metal salts such as sodium or potassium salts; alkaline earth metal salts such as calcium or magnesium salts; zinc salts; ammonium salts; aliphatic amine salts such as trimethylamine, triethylamine, dicyclohexylamine, ethanolamine, diethanolamine, triethanolamine, 12 procaine salts, meglumine salts, ethylenediamine salts, or choline salts; aralkyl amine salts such as N,N- dibenzylethylenediamine salts, benzathine salts, benethamine salts; heterocyclic aromatic amine salts such as pyridine salts, picoline salts, quinoline salts or isoquinoline salts; quaternary ammonium salts such as tetramethylammonium salts, tetraethylammonium salts, benzyltrimethylammonium salts, benzyltriethylammonium salts, benzyltributylammonium salts, methyltrioctylammonium salts or tetrabutylammonium salts; and basic amino acid salts such as arginine salts, lysine salts, or histidine salts. Exemplary acid addition salts comprise, for example: mineral acid salts such as hydrochloride, hydrobromide, hydroiodide, sulfate salts (such as, e.g., sulfate or hydrogensulfate salts), nitrate salts, phosphate salts (such as, e.g., phosphate, hydrogenphosphate, or dihydrogenphosphate salts), carbonate salts, hydrogencarbonate salts, perchlorate salts, borate salts, or thiocyanate salts; organic acid salts such as acetate, propionate, butyrate, pentanoate, hexanoate, heptanoate, octanoate, cyclopentanepropionate, decanoate, undecanoate, oleate, stearate, lactate, maleate, oxalate, fumarate, tartrate, malate, citrate, succinate, adipate, gluconate, glycolate, nicotinate, benzoate, salicylate, ascorbate, pamoate (embonate), camphorate, glucoheptanoate, or pivalate salts; sulfonate salts such as methanesulfonate (mesylate), ethanesulfonate (esylate), 2-hydroxyethanesulfonate (isethionate), benzenesulfonate (besylate), p-toluenesulfonate (tosylate), 2-naphthalenesulfonate (napsylate), 3-phenylsulfonate, or camphorsulfonate salts; glycerophosphate salts; and acidic amino acid salts such as aspartate or glutamate salts. Preferred pharmaceutically acceptable salts of the compounds of formula (I) include a hydrochloride salt, a hydrobromide salt, a mesylate salt, a sulfate salt, a tartrate salt, a fumarate salt, an acetate salt, a citrate salt, and a phosphate salt. A particularly preferred pharmaceutically acceptable salt of the compound of formula (I) is a hydrochloride salt. Accordingly, it is preferred that the compound of formula (I), including any one of the specific compounds of formula (I) described herein, is in the form of a hydrochloride salt, a hydrobromide salt, a mesylate salt, a sulfate salt, a tartrate salt, a fumarate salt, an acetate salt, a citrate salt, or a phosphate salt, and it is particularly preferred that the compound of formula (I) is in the form of a hydrochloride salt.

[0067] The present invention also specifically relates to the compound of formula (I), including any one of the specific compounds of formula (I) described herein, in non-salt form. It is to be understood that when a reference is made to the compound of the present invention, preferably said compound or its pharmaceutically acceptable salt is meant.

[0068] Moreover, the scope of the invention embraces the compounds of formula (I) in any solvated form, including, e.g., solvates with water (i.e., as a hydrate) or solvates with organic solvents such as, e.g., methanol, ethanol, isopropanol, acetic acid, ethyl acetate, ethanolamine, DMSO, or acetonitrile. All 13 physical forms, including any amorphous or crystalline forms (i.e., polymorphs), of the compounds of formula (I) are also encompassed within the scope of the invention. It is to be understood that such solvates and physical forms of pharmaceutically acceptable salts of the compounds of the formula (I) are likewise embraced by the invention.

[0069] Furthermore, the compounds of formula (I) may exist in the form of different isomers, in particular stereoisomers (including, e.g., geometric isomers (or cis / trans isomers), enantiomers and diastereomers) or tautomers (including, in particular, prototropic tautomers, such as keto / enol tautomers or thione / thiol tautomers). All such isomers of the compounds of formula (I) are contemplated as being part of the present invention, either in admixture or in pure or substantially pure form. As for stereoisomers, the invention embraces the isolated optical isomers of the compounds according to the invention as well as any mixtures thereof (including, in particular, racemic mixtures / racemates). The racemates can be resolved by physical methods, such as, e.g., fractional crystallization, separation or crystallization ofdiastereomeric derivatives, or separation by chiral column chromatography. The individual optical isomers can also be obtained from the racemates via salt formation with an optically active acid followed by crystallization. The present invention further encompasses any tautomers of the compounds of formula (I). It will be understood that some compounds may exhibit tautomerism. In such cases, the formulae provided herein expressly depict only one of the possible tautomeric forms. The formulae and chemical names as provided herein are intended to encompass any tautomeric form of the corresponding compound and not to be limited merely to the specific tautomeric form depicted by the drawing or identified by the name of the compound.

[0070] The scope of the invention also embraces compounds of formula (I), in which one or more atoms are replaced by a specific isotope of the corresponding atom. For example, the invention encompasses compounds of formula (I), in which one or more hydrogen atoms (or, e.g., all hydrogen atoms) are replaced by deuterium atoms (i.e.,2H; also referred to as “D”). Accordingly, the invention also embraces compounds of formula (I) which are enriched in deuterium. Naturally occurring hydrogen is an isotopic mixture comprising about 99.98 mol-% hydrogen-1 (1H) and about 0.0156 mol-% deuterium (2H or D). The content of deuterium in one or more hydrogen positions in the compounds of formula (I) can be increased using deuteration techniques known in the art. For example, a compound of formula (I) or a reactant or precursor to be used in the synthesis of the compound of formula (I) can be subjected to an H / D exchange reaction using, e.g., heavy water (D2O). Further suitable deuteration techniques are described in: Atzrodt J et al., Bioorg Med Chem, 20(18), 5658-5667, 2012; William JS et al., Journal of Labelled Compounds and Radiopharmaceuticals, 53(11-12), 635-644, 2010; Modvig A et al., J Org Chem, 14

[0071] 79, 5861-5868, 2014. The content of deuterium can be determined, e.g., using mass spectrometry or NMR spectroscopy. Unless specifically indicated otherwise, it is preferred that the compound of formula (I) is not enriched in deuterium. Accordingly, the presence of naturally occurring hydrogen atoms or1H hydrogen atoms in the compounds of formula (I) is preferred.

[0072] The present invention also embraces compounds of formula (I), in which one or more atoms are replaced by a positron-emitting isotope of the corresponding atom, such as, e.g.,18F,11C,13N,150,76Br,77Br,120l and / or124l. Such compounds can be used as tracers, trackers or imaging probes in positron emission tomography (PET). The invention thus includes (i) compounds of formula (I), in which one or more fluorine atoms (or, e.g., all fluorine atoms) are replaced by18F atoms, (ii) compounds of formula (I), in which one or more carbon atoms (or, e.g., all carbon atoms) are replaced by11C atoms, (ill) compounds of formula (I), in which one or more nitrogen atoms (or, e.g., all nitrogen atoms) are replaced by13N atoms, (iv) compounds of formula (I), in which one or more oxygen atoms (or, e.g., all oxygen atoms) are replaced by15O atoms, (v) compounds of formula (I), in which one or more bromine atoms (or, e.g., all bromine atoms) are replaced by76Br atoms, (vi) compounds of formula (I), in which one or more bromine atoms (or, e.g., all bromine atoms) are replaced by77Br atoms, (vii) compounds of formula (I), in which one or more iodine atoms (or, e.g., all iodine atoms) are replaced by120l atoms, and (viii) compounds of formula (I), in which one or more iodine atoms (or, e.g., all iodine atoms) are replaced by124l atoms. In general, it is preferred that none of the atoms in the compounds of formula (I) are replaced by specific isotopes.

[0073] The present invention further relates to a pharmaceutical composition comprising the compound of the present invention and a pharmaceutically acceptable carrier. The pharmaceutical compositions can be formulated by techniques known to the person skilled in the art, such as the techniques published in “Remington: The Science and Practice of Pharmacy”, Pharmaceutical Press, 22ndedition, which is incorporated herein by reference in its entirety.

[0074] The pharmaceutical compositions may comprise one or more solubility enhancers, such as, e.g., polyethylene glycol), including polyethylene glycol) having a molecular weight in the range of about 200 to about 5,000 Da (e.g., PEG 200, PEG 300, PEG 400, or PEG 600), ethylene glycol, propylene glycol, glycerol, a non-ionic surfactant, tyloxapol, polysorbate 80, macrogol-15-hydroxystearate (e.g., Kolliphor® HS 15, CAS 70142-34-6), a phospholipid, lecithin, dimyristoyl phosphatidylcholine, dipalmitoyl phosphatidylcholine, distearoyl phosphatidylcholine, a cyclodextrin, a-cyclodextrin, β -cyclodextrin, y- cyclodextrin, hydroxyethyl-β -cyclodextrin, hydroxypropyl-β-cyclodextrin, hydroxyethyl-y-cyclodextrin, 15 sulfobutylether-y-cyclodextrin, glucosyl-a-cyclodextrin, glucosyl-β-cyclodextrin, diglucosyl-β-cyclodextrin, maltosyl-a-cyclodextrin, maltosyl-β-cyclodextrin, maltosyl-y-cyclodextrin, maltotriosyl-β-cyclodextrin, maltotriosyl-y-cyclodextrin, dimaltosyl-β-cyclodextrin, methyl---cyclodextrin, a carboxyalkyl thioether, hydroxypropyl methylcellulose, hydroxypropylcellulose, polyvinylpyrrolidone, a vinyl acetate copolymer, vinyl pyrrolidone, sodium lauryl sulfate, dioctyl sodium sulfosuccinate, or any combination thereof.

[0075] The pharmaceutical compositions may also comprise one or more preservatives, particularly one or more antimicrobial preservatives, such as, e.g., benzyl alcohol, chlorobutanol, 2-ethoxyethanol, m-cresol, chlorocresol (e.g., 2-chloro-3-methyl-phenol or 4-chloro-3-methyl-phenol), benzalkonium chloride, benzethonium chloride, benzoic acid (or a pharmaceutically acceptable salt thereof), sorbic acid (or a pharmaceutically acceptable salt thereof), chlorhexidine, thimerosal, or any combination thereof.

[0076] The pharmaceutical composition of the invention is preferably formulated as a unit dosage form. The dosage of the compound will be determined by an attending physician (or, as applicable, an attending veterinarian) according to the needs of the subject. The unit dosage form preferably comprises from 0.1 to about 500 mg of the compound of the present invention.

[0077] The pharmaceutical composition of the invention may comprise the compound of the invention in a pure, substantially pure or partially pure form. In some embodiments, said substantially pure form may comprise at least 95% wt. of said compound, e.g., 96% wt, 97% wt., 98% wt. or more than 99% wt. of said compound.

[0078] The composition may be formulated as a tablet, a pill, a capsule, a powder, granules, a sterile parenteral solution or suspension, a metered aerosol or liquid spray, drops, an ampoule, an auto-injector device, a suppository, a cream or a gel. Said composition may be adapted for oral, enteral parenteral, intrathecal, intranasal, sublingual, rectal or topical administration, or for administration by inhalation or insufflation. Oral compositions such as tablets, pills, capsules or wafers are particularly preferred.

[0079] For preparing a solid dosage form such as a tablet, said compound may be mixed with one or more pharmaceutical excipients, e. g., conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, or other pharmaceutical diluents, e. g., water, to form a solid pre-formulation composition containing a substantially homogeneous mixture of said compound, such that said compound is dispersed evenly throughout the composition, so 16 that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules.

[0080] Said solid pre-formulation composition is then subdivided into unit dosage forms of the kind mentioned above which may each contain from 0.01 to about 500 mg of the compound of the present invention. Preferred unit dosage forms contain from 1 to 500 mg, e.g., 1 , 5, 10, 25, 50, 100, 300, or 500 mg, of the compound of the present invention.

[0081] When formulated as a tablet or pill, said tablet or pill may be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For instance, said tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. These two components may be separated by an enteric layer that serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials are known in the use in such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate.

[0082] Alternatively, the pharmaceutical composition of the present invention may be formulated as a liquid dosage form for administration orally or by injection; for example, an aqueous solution, a suitably flavoured syrup, an aqueous or oil suspension or a flavoured emulsion with edible oils such, for example, as cottonseed oil, sesame oil, coconut oil or peanut oil, as well as an elixir or a similar pharmaceutical vehicle. Suitable dispersing or suspending agents for an aqueous suspension include synthetic and natural gums, e.g., tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone or gelatin.

[0083] The pharmaceutical composition of the present invention may also comprise acetaminophen, one or more other NSAIDs, one or more weak or strong opioids, an antidepressant or an antiepileptic agent.

[0084] The present invention provides the compound of formula (I), including its particularly preferred form, the compound of formula (le), for use in the treatment or prophylaxis of a disease selected from pain, inflammation and autoimmune disease. The disease is preferably pain.

[0085] The compound of the present invention is provided for use in the treatment or prevention of a disease, as described in the following. 17

[0086] The compound of the present invention may be used for the treatment or prophylaxis of acute or chronic pain. For instance, the compound may be used for the treatment of nociceptive pain such, for example, as cutaneous pain, somatic pain, myofascial pain, visceral pain, phantom limb pain or neuropathic pain. The compound of the invention may also be used in the treatment of headaches or migraine. The compound may be used alone or in combination with acetaminophen or another NSAID for the treatment of mild chronic pain or in conjunction with weak or strong opioids for the treatment of moderate or severe pain.

[0087] The neuropathic pain, as referred to herein, may be associated with peripheral sensory neuropathy, which may be selected from diabetic neuropathy, post-herpetic neuropathy, lumbago, sacral pain, surgical pain, crush injury, spinal injury, complex regional pain syndrome, phantom limb sensations, peripheral sensory neuropathy associated with osteoarthritis, peripheral sensory neuropathy associated with rheumatoid arthritis, peripheral sensory neuropathy associated with autoimmune osteoarthrosis, cephalea, fibromyalgia, peripheral sensory neuropathy induced by antiblastic therapies, peripheral sensory neuropathy induced by a chemotherapeutic agent, peripheral sensory neuropathy associated with visceral injury, peripheral sensory neuropathy associated with osteonecrosis, peripheral sensory neuropathy associated with human immunodeficiency virus infection, peripheral neuropathic pain, or peripheral sensory neuropathy induced by an antiviral agent.

[0088] The compound of the invention may also be employed in the treatment or prophylaxis of neuropathic pain and may be used in conjunction with one or more antidepressants or antiepileptic medicaments such, for example, as gabapentin or pregabalin. According to another aspect of the present invention therefore there is provided a method for treating or preventing pain, inflammation and / or autoimmune disease in a human or non-human animal patient, which method comprises administering to said patient in need thereof a therapeutic effective amount of the compound of the invention. For a human patient, a daily dose of 0.01 mg to 15 g, preferably 1.0 mg to 15 g of said compound in a pure, substantially pure or partially pure form as described in more detail below may suitably be administered. The compound may be administered under the supervision of a medical practitioner in an amount sufficient to achieve effective pain management. In some embodiments, the daily dose of said compound may be titrated to determine such effective amount. Said daily dose may comprise about 5.0 mg to 1 g, typically about 5 mg to 500 mg. In some embodiments, said dose may comprise 10 mg to 100 mg per day of the compound. However, administration of daily doses of less than 5.0 mg of the compound of the invention is also possible within the present invention. The compound may be administered at once, or the administration may be divided 18 in several doses, distributed over the day. Accordingly, the compound may be preferably administered on a regimen of one to four times per day. Said compound may be administered parenterally, transdermally, intramuscularly, intravenously, intradermally, intranasally, subcutaneously, intraperitoneally, intraventricularly, intrathecally or rectally. Preferably, the compound is administered orally.

[0089] Optionally, the compound of the present invention may be administered simultaneously, sequentially or separately with at least one opioid analgesic, an antidepressant or an antiepileptic medicament. Alternatively, the compound of the invention may be administered simultaneously, sequentially or separately with one or more other NSAIDs or acetaminophen.

[0090] The compound of the present invention may be used for the treatment or prevention of autoimmune disease. In a preferred embodiment of the invention, the autoimmune disease is celiac disease, diabetes mellitus type 1 , sarcoidosis, systemic lupus erythematosus (SLE), Sjogren’s syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto’s thyroiditis, Graves’ disease, idiopathic thrombocytopenic purpura, Addison’s disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM), ulcerative colitis (UC) or multiple sclerosis (MS).

[0091] The present invention also relates to the use of the compound of the invention in the manufacture of a medicament for use in the treatment or prophylaxis of a disease, as described herein. Preferably, the diseases is pain, inflammation or autoimmune disease. More preferably, the disease is pain. Said medicament may be manufactured for coadministration with one or more of acetaminophen, another NSAID, an opioid, an antiepileptic or an antidepressant. In one specific embodiment, the invention provides the use of the compound of the invention in the manufacture of a medicament for use in the treatment or prevention of inflammation. In another specific embodiment, the invention provides the use of the compound of the invention in the manufacture of a medicament in the treatment or prevention of autoimmune disease.

[0092] The present invention further provides a method for treating a disease in a subject in need thereof, wherein the method comprises administering to said subject a therapeutically effective amount of the compound. In this method, a daily dose of 0.01 mg to 15 g of the compound of the invention is administered (preferred daily doses include 1 .0 mg to 15 g, preferably 5.0 mg to 1 g, more preferably 5 mg to 500 mg, even more preferably 10 mg to 100 mg of the compound). The compound is preferably administered orally. The disease is selected from pain, inflammation and autoimmune disease, and is as described hereinabove. 19

[0093] The following definitions apply throughout the present specification, unless specifically indicated otherwise.

[0094] As used herein, the term “alkyl” refers to a monovalent saturated acyclic (i.e., non-cyclic) hydrocarbon group which may be linear or branched. Accordingly, an “alkyl” group does not comprise any carbon-to- carbon double bond or any carbon-to-carbon triple bond. A “C1-5alkyl” denotes an alkyl group having 1 to 5 carbon atoms. Preferred exemplary alkyl groups are methyl, ethyl, propyl (e.g., n-propyl or isopropyl), or butyl (e.g., n-butyl, isobutyl, sec-butyl, or tert-butyl). Unless defined otherwise, the term “alkyl” preferably refers to C1-4alkyl, more preferably to methyl or ethyl, and even more preferably to methyl.

[0095] The “treatment” of a disorder or disease may, for example, lead to a halt in the progression of the disorder or disease (e.g., no deterioration of symptoms) or a delay in the progression of the disorder or disease (in case the halt in progression is of a transient nature only). The “treatment” of a disorder or disease may also lead to a partial response (e.g., amelioration of symptoms) or complete response (e.g., disappearance of symptoms) of the subject / patient suffering from the disorder or disease. Accordingly, the “treatment” of a disorder or disease may also refer to an amelioration of the disorder or disease, which may, e.g., lead to a halt in the progression of the disorder or disease or a delay in the progression of the disorder or disease. Such a partial or complete response may be followed by a relapse. It is to be understood that a subject / patient may experience a broad range of responses to a treatment (such as the exemplary responses as described herein above). The treatment of a disorder or disease may, inter alia, comprise curative treatment (e.g. disease modifying, preferably leading to a complete response and eventually to healing of the disorder or disease) and palliative treatment (including symptomatic relief).

[0096] The term “prevention” or “prophylaxis” of a disorder or disease as used herein is also well known in the art. For example, a patient / subject suspected of being prone to suffer from a disorder or disease may particularly benefit from a prevention of the disorder or disease. The subject / patient may have a susceptibility or predisposition for a disorder or disease, including but not limited to hereditary predisposition. Such a predisposition can be determined by standard methods or assays, using, e.g., genetic markers or phenotypic indicators. It is to be understood that a disorder or disease to be prevented in accordance with the present invention has not been diagnosed or cannot be diagnosed in the patient / subject (for example, the patient / subject does not show any clinical or pathological symptoms). Thus, the term “prevention” or “prophylaxis” comprises the use of the compound of the present invention before any clinical and / or pathological symptoms are diagnosed or determined or can be diagnosed or determined by the attending physician. 20

[0097] It is to be understood herein that the term “treatment or prevention” preferably refers to “treatment”, as described herein.

[0098] The subject is not meant to be particularly limited and both human and animal subject may be meant. Preferably, the subject is a human subject.

[0099] The term “about” preferably refers to ±10% of the indicated numerical value, more preferably to ±5% of the indicated numerical value, and in particular to the exact numerical value indicated. For example, the expression “about 100” preferably refers to 100 ±10% (i.e., 90 to 110), more preferably to 100 ±5% (i.e., 95 to 105), and even more preferably to the specific value of 100. If the term “about” is used in connection with the endpoints of a range, it preferably refers to the range from the lower endpoint 10% of its indicated numerical value to the upper endpoint +10% of its indicated numerical value, more preferably to the range from of the lower endpoint 5% to the upper endpoint +5%, and even more preferably to the range defined by the exact numerical values of the lower endpoint and the upper endpoint. Thus, the expression “about 10 to about 20” preferably refers to the range of 9 to 22, more preferably to the range of 9.5 to 21 , and even more preferably to the range of 10 to 20. If the term “about” is used in connection with the endpoint of an open-ended range, it preferably refers to the corresponding range starting from the lower endpoint 10% or from the upper endpoint +10%, more preferably to the range starting from the lower endpoint 5% or from the upper endpoint +5%, and even more preferably to the open-ended range defined by the exact numerical value of the corresponding endpoint. For example, the expression “at least about 10%” preferably refers to at least 9%, more preferably to at least 9.5%, and even more preferably to at least 10%.

[0100] The term substantially pure preferably refers to a purity of at least 95% wt. e.g., 96% wt., 97% wt., 98% wt. or more than 99% wt. The term “substantially free” of a particular impurity may preferably be interpreted as comprising not more than 10%wt of this particular impurity, preferably not more than 5%wt, more preferably not more than 2%wt, even more preferably not more than 1 %wt of said particular impurity. The term substantially no effect on the activity refers preferably to activity being affected by less than 10%, more preferably by less than 5%, even more preferably less than 2%. The term “substantially homogeneous” preferably refers to a situation wherein the skilled person cannot detect any inhomogeneity using state of the art inspection methods. 21

[0101] The terms “optional", “optionally” and “may” denote that the indicated feature may be present but can also be absent. Whenever the term “optional”, “optionally” or “may” is used, the present invention specifically relates to both possibilities, i.e., that the corresponding feature is present or, alternatively, that the corresponding feature is absent. For example, if a component of a composition is indicated to be “optional”, the invention specifically relates to both possibilities, i.e., that the corresponding component is present (contained in the composition) or that the corresponding component is absent from the composition.

[0102] The term "comprising” (or “comprise”, “comprises”, “contain”, “contains", or “containing”), unless explicitly indicated otherwise or contradicted by context, has the meaning of “containing, inter alia”, i.e., “containing, among further optional elements, ...”. In addition thereto, this term also includes the narrower meanings of “consisting essentially of’ and “consisting of. For example, the term “A comprising B and C” has the meaning of “A containing, inter alia, B and C”, wherein A may contain further optional elements (e.g., “A containing B, C and D” would also be encompassed), but this term also includes the meaning of “A consisting essentially of B and C” and the meaning of “A consisting of B and C” (i.e., no other components than B and C are comprised in A).

[0103] Any parameters referred to herein (including, e.g., any amounts / concentrations indicated in “mg / ml” or in “% (v / v)”, and any pH values) are preferably to be determined at standard ambient temperature and pressure conditions, particularly at a temperature of 25°C (298.15 K) and at an absolute pressure of 1 atm (101.325 kPa).

[0104] It is to be understood that the present invention specifically relates to each and every combination of features and embodiments described herein, including any combination of general and / or preferred features / embodiments.

[0105] In this specification, a number of documents including patent applications and scientific literature are cited. The disclosure of these documents, while not considered relevant for the patentability of this invention, is herewith incorporated by reference in its entirety. More specifically, all referenced documents are incorporated by reference to the same extent as if each individual document was specifically and individually indicated to be incorporated by reference.

[0106] The invention will be illustrated by the following examples, which however are not to be construed as limiting. 22

[0107] Examples

[0108] Example 1 - Synthesis of the compound (S,S)-(3-O-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene (also referred to as M25 or the compound of formula (le))

[0109] The compound M25 was prepared as in the following scheme 1. Chemical synthesis was performed by Wuxi AppTec Co. Ltd., as in the following.

[0110] The details of synthetic procedures are provided in the following.

[0111] To a solution of (S)-2-Amino-3-[4-(phenylmethoxy)phenyl]-1 -propanol (M23-3a) (5.00 g, 19.4 mmol, 1.00 eq) in DMSO (50.0 ml) was added t-BuOK (10.9 g, 97.2 mmol, 5.00 eq), 18-Crown-6 (10.3 g, 38.9 mmol, 2.00 eq) and CZXY4 (7.12 g, 29.2 mmol, 1.50 eq). The mixture was stirred at 50 °C for 12 hrs. LCMS (EC7805-16-P1A1) showed 39.0% of M23-3a remained and 41.6% of desired mass was detected. The reaction mixture was quenched by addition of H2O (50.0 ml) at 25 °C, and then extracted with EtOAc (50.0 ml * 3). The combined organic layers were washed with brine (100 ml), dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, CH2CI2 : MeOH = 10 : 1 to 5 : 1) to give the M25-1 (4.08 g, 10.1 mmol, 51.8% yield) as a yellow oil, which was confirmed by1H-NMR (EC7805-16-P1A5) and 2D NMR. 23

[0112] LCMS: RT = 0.435 min, M+H+= 406.5.

[0113] 1HNMR: (400 MHz, DMSO-d6) δ 7.46 - 7.41 (m, 2H), 7.41 - 7.35 (m, 2H), 7.35 - 7.30 (m, 5H), 7.29 - 7.23 (m, 1 H), 7.06 (d, J = 8.6 Hz, 2H), 6.87 (d, J = 8.6 Hz, 2H), 5.05 (s, 2H), 4.56 - 4.51 (m, 2H), 3.71 - 3.61 (m, 1H), 3.46 - 3.40 (m, 2H), 3.26 - 3.19 (m, 2H), 3.04 - 2.92 (m, 1H), 2.66 - 2.57 (m, 1H), 2.45 - 2.36 (m, 1 H), 1.14 - 1.10 (m, 3H).

[0114] 2D NMR HSQC and HMBC spectra are shown in Figure 2.

[0115] General procedure for preparation of M25

[0116] To a solution of M25-1 (1 .00 g, 2.47 mmol, 1.00 eq) in MeOH (10.0 mL) was added Pd / C (200 mg, 10% purity) in Ar atmosphere. The suspension was degassed and purged with H2 for 3 times. The mixture was stirred under H2 (50 Psi) at 50 °C for 12 hrs. LCMS (EC7805-20-P1A2) showed none of M25-1 remained and 97.8% of desired mass was detected. The mixture was filtered and washed with THF (50.0 ml). The filter cake was purified by reversed-phase HPLC (column: Phenomenex Luna C18 200*40mm*10um;mobile phase: [water(HCI)-ACN];B%: 1 %-20%,10 min) to give M25 (260 mg, 967 umol, 39.2% yield, 97.3% purity, MCI) as a white solid, which was confirmed by LCMS, HPLC, HNMR and QNMR.

[0117] LCMS: RT = 0.273 min, M+H+= 226.4.

[0118] HPLC: RT = 1.133 min, 97.3% purity.

[0119] 1HNMR: (400 MHz, DMSO-d6) δ 8.23 (s, 2H), 7.01 (d, J = 8.4 Hz, 2H), 6.71 (d, J = 8.4 Hz, 2H), 3.82 - 3.66 (m, 1 H), 3.51 - 3.24 (m, 3H), 3.23 - 3.12 (m, 2H), 2.92 - 2.83 (m, 1 H), 2.75 - 2.65 (m, 1 H), 1.00 (d, J = 6.4 Hz, 3H).

[0120] Example 2 - spinal nerve ligation (snl) model of neuropathic pain in rats

[0121] The animal studies described herein were performed at MD Biosciences Innovalora Ltd., 4 Eli Horovitz St., Rehovot 7608810, Israel. 24

[0122] The objective of this study was to evaluate and compare the analgesic activity of (S,S)-2-N(3-O-(propan- 2-ol)-1-propyl-4-hydroxybenzene)-3-phenylpropylamide (referred to as NRD135S.E1 or briefly NRD) and its metabolite (S,S)-(3-O-(propan-2-ol)-2-amino-prop-1-yl-4-hydroxybenzene (also referred to as M25) in the SNL (Chung) rat model. Accordingly, neuropathic pain was evaluated by the Von Frey test (mechanical allodynia) and the Cold Plate test (thermal hyperalgesia). Gabapentin was used as positive control for analgesic effects. Following test item administration, resulting plasma levels were determined by a “fit-for-purpose" LC-MS / MS method in order to relate pharmacological effects to drug exposures.

[0123] Preparation of test items:

[0124] In the following, the protocols applied in this study are provided.

[0125] Vehicle as a solvent for PO dosing: DMSO / Saline (25% / 75% v / v) :

[0126] Preparation of 10 ml:

[0127] 1.Mix 2.5 ml DMSO with 7.5 ml Saline.

[0128] Vehicle (Group 1) and as a solvent for IV dosing: Propylene glycol / Ringer lactate (25% / 75% v / v):

[0129] Preparation of 100 ml:

[0130] Mix 25 ml Propylene glycol with 75 ml Ringer lactate.

[0131] Preparation of Gabapentin (Positive control) at a dose level of 150 mg / kg, at a dose volume of 3 mL / kg, and at a concentration of 50 mg / ml (Group 2):

[0132] Gabapentin exists as a powder. To prepare a working solution of 50 mg / ml, 250 mg of gabapentin is dissolved in 5 ml saline.

[0133] Note: A rat weighing 300 g is to be injected with 0.9 ml of dissolved gabapentin solution.

[0134] NRD and M25 IV dosing

[0135] NRD (Group 3) is to be dosed as IV bolus over 2 min followed immediately by 30 min infusion.

[0136] M25 (Groups 4-6) is to be dosed as IV bolus over 1 min followed immediately by 30 min infusion.

[0137] Aliquots of NRD and M25 administration solutions (Groups 3-7) are to be collected immediately after preparation and also after infusion / PO dosing and stored at -80°C for analysis.

[0138] 10 mg of M25 power are to be weighed and stored at Room Temperature for analysis. 25

[0139] 5.4.4 Preparation of NRD (Group 3) at dose levels of IV bolus: 1.65 mg / kg and IV infusion: 8.16 mg / kg / h, at a concentration of 3.3 mg / ml:

[0140] IV bolus: 0.5 ml / kg (~0.15ml / rat 300g)

[0141] Infusion rate for IV infusion: 2.47 ml / kg / h (~0.375ml / rat 300g / 30min)

[0142] Preparation of 10 ml:

[0143] 1.Weigh 33 mg of NRD135S.E1 ;

[0144] 2. Dissolve in 10 ml of Vehicle (see section 5.4.2);

[0145] 3. Mix well.

[0146] Preparation of M25 (Group 4) at dose levels of IV bolus: 0.137 mg / kg and IV infusion: 3.38 mg / kg / h, at a concentration of 0.457 mg / ml:

[0147] IV bolus: 0.3 ml / kg (~90 pl / rat 300g)

[0148] Infusion rate for IV infusion: 7.40 ml / kg / h (~1.11 ml / rat 300g / 30min)

[0149] Preparation of 10 ml:

[0150] 1.Weigh 4.57 mg of M25;

[0151] 2.Dissolve in 10 ml of Vehicle (see section 5.4.2);

[0152] 3.Mix well. or alternatively:

[0153] 1.Take 2 ml M25 at a concentration of 2.29 mg / ml (see below);

[0154] 2.Add 8 ml of Vehicle (see above);

[0155] 3.Mix well.

[0156] Preparation of M25 (Group 5) at a dose levels of IV bolus: 0.685 mg / kg and IV infusion: 16.9 mg / kg / h, and at a concentration of 2.29 mg / ml:

[0157] IV bolus: 0.3 ml / kg (~90 pl / rat 300g)

[0158] Infusion rate for IV infusion: 7.40 ml / kg / h (~1.11 ml / rat 300g / 30min)

[0159] Preparation of 10 ml:

[0160] 1.Weigh 22.9 mg of M25;

[0161] 2. Add 10 ml of Vehicle (see above); 26

[0162] 3. Mix well.

[0163] Preparation of M25 (Group 6) at a dose level of IV bolus: 0.0274 mg / kg and IV infusion: 0.676 mg / kg / h, at a concentration of 0.0914 mg / ml:

[0164] IV bolus: 0.3 ml / kg (~90 pl / rat 300g)

[0165] Infusion rate for IV infusion: 7.40 ml / kg / h (~1.11 ml / rat 300g / 30min)

[0166] Preparation of 30 ml:

[0167] 1.Weigh 2.74 mg of M25;

[0168] 2. Add 30 ml of Vehicle (see section);

[0169] 3. Mix well. or alternatively:

[0170] 1.Take 0.4 ml M25 at a concentration of 2.29 mg / ml (see above);

[0171] 2.Add 9.6 ml of Vehicle (see section 5.4.2);

[0172] 3.Mix well.

[0173] Preparation of NRD (Group 7) at an oral dose level of 80 mg / kg, at a dose volume of 5 ml / kg, and at a concentration of 16 mg / ml:

[0174] Preparation of 10 ml:

[0175] 1.Weigh 160 mg of NRD;

[0176] 2. Add 10 ml of Vehicle (see above);

[0177] 3.Mix well.

[0178] Note: A rat weighing 300 g is to be dosed orally by gavage with 1.5 ml of the solution.

[0179] The tests are performed in SD Rats provided by Envigo RMS (Israel), Ltd. The rat has been selected as it represented the species of choice for this experimental animal model with documented relevance for the evaluation of neuropathic pain. The rats are young adult male rats (140-170 g). The total number of animals, after inclusion, is n=70. Weight variation of animals at the time of treatment initiation should not exceed ± 20% of the mean weight. The health status of the animals used in this study is examined upon their arrival and recorded in the rodents receiving log book. The following parameters are examined by the animals’ caretaker: date of arrival, gender, date of birth and animals weight. Only animals in good 27 health are acclimatized to laboratory conditions and are used in the study. The acclimnation is at least 5 days. During acclimation and throughout the entire study duration, animals are housed within a limited access rodent facility and kept in groups with a maximum of 3 rats per polypropylene cage. The cages are fitted with solid bottoms and filled with sterile wood shavings as bedding material. Animals are provided ad libitum with a commercial rodent diet and have free access to drinking water that is supplied to each cage via polyethylene bottles with stainless steel sipper tubes. A feed lot analysis of the diet batch used in the study will be included in the archives with the study data. Sufficient supply, consumption and unrestricted access of water are monitored. Automatically controlled environmental conditions are set to maintain temperature at 17-23°C with a relative humidity (RH) of 30-70%, a 12:12 hour light: dark cycle and 15-30 air changes / hour in the study room. Temperature and RH are monitored daily. Animals are given a unique animal identification tail mark. This number also appears on a cage card on the front of each cage. The cage card also contains the study and group numbers, route of administration, gender, strain, and all other relevant details as to treatment group. During the acclimation period, animals are randomly assigned to experimental groups according to body weight, such that average starting body weight is similar. Each dosing group is kept in separate cages to avoid cross-contamination which can occur through consumption of fecal matter during the study. At the end of the study, surviving animals are euthanized by pentobarbital injection.

[0180] The Table 1 below lists the seven experimental groups that are comprised in this study.

[0181] Table 1. Experimental animal groups.

[0182] 28

[0183] *Note: Cold plate test will be performed immediately after VF test. Von Frey time points are post PO / IP dosing or after the end of the infusion.

[0184] ** 2 min for NRD, 1 min for M25

[0185] Principles of the Chung Induced Model

[0186] The Chung model is a model for neuropathic pain evaluation. While under anesthesia using medetomine

[0187] / ketamine sodium and after the area is shaved, the rat is placed in a prone position and the left paraspinal muscles are separated from the spinous process at the L4-S2 levels. The 16 vertebral transverse process is carefully removed with a small rongeur to visually identify the L5-L6 spinal nerves. A tight knot is performed (ligation) surrounding the left L5+L6 spinal nerves using 6-0 silk thread. The muscle is then closed with 3-0 silk sutures and the skin is closed by a clamp. Following surgery, the rats are returned to the cage and remained under a heating lamp until they awake.

[0188] One day after surgery, animals will be checked for damaged 14 nerve. If the animal cannot move its leg, it will be excluded from the study. Inclusion of animals will be performed on post-operative day 13 based 29 on Von Frey test. Animals with a pain threshold of ≤ 15 g for an operated leg following Von Frey testing will be included in the study.

[0189] Test Items (Groups 3-6) are to be administered as IV bolus (2 min for Group 3, 1 min for Groups 4-6) followed immediately by a 30-min infusion intra-jugular vein on day 14. The procedure is to be performed under isoflurane anesthesia (5% for induction followed by 2.5% for maintenance).

[0190] The description of the study is provided in Table 2 below and summarized in the following.

[0191] Seven groups of 10 animals each were treated on Day 14 after SNL surgery (conducted on Day 0) with a single dose of vehicle, NRD or M25 (three different dose levels, covering a 25-fold range). Groups 1 and 3 to 6 were given IV as a bolus injection followed by a 30-min infusion. Test item NRD (Group 7) was additionally dosed PO. The positive control Gabapentin (Group 2) was dosed intraperitoneally (IP).

[0192] Assessments included:

[0193] Body weight on study Day 0, and on study Days 7 and 13 (i.e., the day before drug treatment).

[0194] Measurements of mechanical pain sensitivity (Von Frey test) in all animals on study Days -1 (baseline), 13, 14 (1 , 4, 8h post dosing), 15 (24h post dosing)

[0195] Cold Plate tests in all animals always immediately after the Von Frey test.

[0196] Blood samples for plasma level determinations of NRD and M25 in Groups 3-7 (before drug treatment from all 9 animals per group; post administration 1h (from animals #1-3 in each Group), 4h (from #4-6), 8h (from #7-9), 24h (from #1-3)).

[0197] No deviations from the study protocol were noted during study conduct.

[0198] Table 2. Summary of the study plan.

[0199] 30

[0200] Observations and examinations

[0201] Throughout the study, general clinical examinations are performed and recorded if any unexpected abnormalities are observed. Observations include changes in skin, fur, eyes, mucous membranes, occurrence of secretions and excretions (e.g. diarrhea), piloerection, unusual respiratory pattern, changes in gait, posture and response to handling. Body weights will be measured on Days 0 (before surgery) and then on days 7 and 13.

[0202] Experimental materials

[0203] The list of experimental materials and their origin are listed in the following Table 3. 31

[0204] Table 3. List of experimental materials.

[0205] Preparation of the test items

[0206] Vehicle as a solvent for PO dosing: DMSO / Saline (25% / 75%v / v):

[0207] Preparation of 10 ml:

[0208] 1. Mix 2.5 ml DMSO with 7.5 ml Saline.

[0209] Vehicle (Group 1) and as a solvent for IV dosing: Propylene glycoVRinger lactate (25*hf75% v / v):

[0210] Preparation of 100 ml:

[0211] 1. Mix 25 ml Propylene glycol with 75 ml Ringer lactate. 32

[0212] Preparation of Gabapentin (Positive control) at a dose level of 150 mg / kg, at a dose volume of 3 ml / kg and at a concentration of 50 mg / ml (Group 2):

[0213] Gabapentin exists as a powder. To prepare a working solution of 50 mg / ml, 250 mg of gabapentin is dissolved in 5 ml saline.

[0214] Note: A rat weighing 300 g is injected with 0.9 ml of dissolved gabapentin solution.

[0215] NRD and M25 IV dosing NRD (Group 3) is dosed as IV bolus over 2 min followed immediately by 30 min infusion.

[0216] M25 (Groups 4-6) are dosed as IV bolus over 1 min followed immediately by 30 min infusion.

[0217] Aliquots of NRD and M25 administration solutions (Groups 3-7) are collected immediately after preparation and also after infusion / PO dosing and stored at -80°C for analysis.

[0218] 10 mg of M25 power are weighed and stored at Room Temperature for analysis.

[0219] Preparation of NRD (Group 3) at dose levels of IV bolus: 1 .65 mg / kg and IV infusion: 8.16 mg / kg / h, at a concentration of 3.3 mg / ml:

[0220] IV bolus: 0.5 ml / kg (— 0.15mlrat 300g)

[0221] Infusion rate for IV infusion: 2.47 ml / kg / h ( 0.375ml / rat 300g / 30min)

[0222] Preparation of 10 ml:

[0223] 1. Weigh 33 mg of NRD135S.E1 ;

[0224] 2. Dissolve in 10 ml of Vehicle;

[0225] 3. Mix well.

[0226] Preparation of M25 (Group 4) at dose levels of IV bolus: 0.137 mg / kg and IV infusion: 3.38 mg / kg / h, at a concentration of 0.457 mg / ml: 33

[0227] IV bolus: 0.3 ml / kg (—90 pl / rat 300g)

[0228] Infusion rate for IV infusion: 7.40 ml / kg / h (-l.llml / rat 300g / 30min)

[0229] Preparation of 10 ml:

[0230] 1. Weigh 4.57 mg of M25;

[0231] 2. Dissolve in 10 ml of Vehicle;

[0232] 3. Mix well. or:

[0233] 1. Take 2 ml M25 at a concentration of 2.29 mg / ml;

[0234] 2. Add 8 ml of Vehicle;

[0235] 3. Mix well.

[0236] Preparation of M25 (Group 5) at a dose levels of IV bolus: 0.685 mg / kg and IV infusion: 16.9 mg / kg / h, and at a concentration of 2.29 mg / ml:

[0237] IV bolus: 0.3 ml / kg (— 90 jil / rat 300g)

[0238] Infusion rate for IV infusion: 7.40 ml / kg / h ( — l.llml / rat 300g / 30min)

[0239] Preparation of 10 ml:

[0240] 1. Weigh 22.9 mg of M25;

[0241] 2. Add 10 ml of Vehicle (see section 5.4.2);

[0242] 3. Mix well.

[0243] Preparation of M25 (Group 6) at a dose level of IV bolus: 0.0274 mg / kg and IV infusion: 0,676 mg / kg / h, at a concentration of 0.0914 mg / ml:

[0244] IV bolus: 0.3 ml / kg (—90 ulrat 300g)

[0245] Infusion rate for IV infusion: 7.40 ml / kg / h (— l.llml / rat 300g / 30min)

[0246] Preparation of 30 ml:

[0247] 1. Weigh 2.74 mg of M25;

[0248] 2. Add 30 ml of Vehicle

[0249] 3. Mix well. or:

[0250] 1. Take 0.4 ml M25 at a concentration of 2.29 mg / ml;

[0251] 2. Add 9.6 ml of Vehicle; 34

[0252] 3. Mix well.

[0253] Preparation of NRD (Group 7) at an oral dose level of 80 mg / kg, at a dose volume of 5 ml / kg and at a concentration of 16 mg / ml:

[0254] Preparation of 10 ml:

[0255] 1. Weigh 160 mg of NRD;

[0256] 2. Add 10 ml of Vehicle;

[0257] 3. Mix well.

[0258] Note: A rat weighing 300 g is to be dosed orally by gavage with 1.5 ml of the solution.

[0259] Test procedures

[0260] General clinical signs

[0261] Throughout the study, general clinical examinations were performed and it was recorded if any unexpected abnormalities were observed. Changes in skin, fur, eyes, mucous membranes, occurrence of secretions and excretions (e.g., diarrhea), piloerection, and unusual respiratory pattern, changes in gait, posture and response to handling were specifically evaluated.

[0262] Body weight

[0263] Body weights were measured on Days 0 (before surgery) and then on Days 7 and 13.

[0264] Spinal Nerve Ligation (Chung model)

[0265] While under anesthesia using medetomidine / ketamine sodium and after the skin area was shaved, the rat was placed in a prone position and the left paraspinal muscles were separated from the spinous process at the L4-S2 levels. The L6 vertebral transverse process was carefully removed with a small rongeur to visually identify the L5-L6 spinal nerves. A tight knot was performed (ligation) surrounding the left L5+L6 spinal nerves using 6-0 silk thread. The muscle was then closed with 3-0 silk sutures and the skin was closed by a clamp. Following surgery, the rats were returned to the cage and remained under a heating lamp until awaking. 35

[0266] One day after SNL surgery, animals were to be checked for damaged L4 nerve. If the animal could not move its leg, it was to be excluded from the study. Inclusion of animals was to be performed on postoperative Day 13 and was based on the Von Frey test. Animals with a pain threshold of < 15 g for an operated leg following Von Frey testing were included in the study.

[0267] Pain response evaluation

[0268] Mechanical Allodynia Evaluation (Von Frey Testing):

[0269] Allodynic response to tactile stimulation is assessed using the Von Frey apparatus (Touch Test®).

[0270] The rat will be placed in an enclosure and positioned on a metal mesh surface, but allowed to move freely. The test begins after a cessation of exploratory behavior. The set of Von Frey monofilaments provide an approximate logarithmic scale of actual force and a linear scale of perceived intensity.

[0271] The operating principle: When the tip of a fiber of given length and diameter is pressed against the skin at right angles, the force of application increases as long as the researcher continues to advance the probe until the fiber bends. After the fiber bends, the probe continues to advance, causing the fiber to bend more, but without additional force being applied. The relationship between the applied force and size of the fiber is provided in the Table below.

[0272] Rodents exhibit a paw withdrawal reflex when the paw is unexpectedly touched. The Touch Test™ Sensory Evaluator can be used on the plantar surfaces of the rat’s foot. The animal will indicate sensation by pulling back its paw. The minimal force needed to elevate the withdrawal reflex is considered / designated as the value of reference. Decreases in force needed to induce withdrawal are indicative of allodynia, as the force applied is a non-painful stimulus under normal conditions.

[0273] Testing will be performed on the left paw before SNL surgery (day -1 ) for baseline level, on study day 13 (inclusion), on day 14 (1 h, 4h and 8h post dosing) and on day 15 (24h post dosing).

[0274] Cold plate test 36

[0275] This test monitors the animal’s natural response to cold. The temperature of the plate beneath the animal's paws is set to 2-4°C. The animal is placed on the plate and the latency time to withdrawal, shaking or licking the paws is recorded. An analgesic drug would lead to an increase in the withdrawal latency time.

[0276] Cold plate test will be measured on day -1 (baseline), on study day 13 (inclusion), on day 14 (1 h, 4h and 8h post dosing) and on day 15 (24h post dosing), immediately after the VF test.

[0277] Intravenous (IV) Administration of Test Items and Vehicle (Groups 3-6, 1)

[0278] Test Items (Groups 3-6) or Vehicle (Group 1) were administered as IV bolus (2 min for Group 3, 1 min for Group 4-6) followed immediately by a 30-min infusion into the jugular vein on Day 14. The procedure was performed under isoflurane anesthesia (5% for induction followed by 2.5% for maintenance).

[0279] Bioanalysis

[0280] NRD and M25 levels in plasma samples collected for pharmacokinetic analysis were determined using an LC-MS / MS method validated to "fit for purpose" degree. Method validation included linearity, precision and accuracy.

[0281] A single internal standard, NRD135S.E1-d3 was used for both analytes. Even though the results showed that the determination of M25 in plasma was possible with sufficient accuracy and precision in the context of this study, a stable labelled isotopic standard of M25 would compensate better for the determination of M25 in plasma.

[0282] Predictions for concentration levels to be determined in the study were too high. Hence, the lowest calibration point used (100 ng / mL) was higher than most of the concentrations actually measured in the study samples. The linearity of the calibration curve justified extrapolation to concentrations lower than 100 ng / mL. The lower limit of determination was estimated at 10 ng / mL.

[0283] Statistical data evaluation

[0284] Data of the Von Frey and Cold Plate testing are presented as means ± SEM. Each treatment group was compared to the vehicle-treated group using a two-way ANOVA followed by Dunnett's post-hoc test 37

[0285] (GraphPad). Each time point was compared to pre-dosing in each group using again a two-way ANOVA followed by Dunnett’s post hoc test. Pre-dosing values were compared to the baseline using Student’s t- test. A p-value <0.05 was considered to represent a statistically significant difference. Net effects in the Von Frey and Cold Plate tests were calculated by subtracting from effects measured after treatment with an active compound the effects after vehicle treatment. A response integral over the entire observation period was obtained by calculating areas under the effect-time curve (AUEC) using the linear trapezoidal rule.

[0286] Pharmacokinetic analysis

[0287] Concentration-time data for NRD and M25 were evaluated descriptively. Concentrations observed in the three animals from each treatment group sampled at the same time point were averaged for calculation of exposure measures. Areas under the plasma concentration-time curve (AUG) were derived by the linear-linear trapezoidal rule, maximum concentrations (Cmax) and the time of their occurrence (Tmax) following oral administration were read directly from the observed concentration-time data.

[0288] In order to obtain an estimate of total exposure (AUC0-24h) after intravenous administrations of test items (NRD, M25), concentrations at the end of the 30-min infusion were estimated from a log-linear back- extrapolation using the 1 h and 4h concentrations. AUC0-24h was then estimated applying the linear-linear trapezoidal rule to the combination of observed and estimated concentrations. All AUC0- 24h values reported in tables and graphs are based on this method of exposure estimation.

[0289] Blood collection

[0290] Before dosing (9 animals) and at each time point after the behavior assessment, from 3 animals of each group dosed with TIs (Groups 3-7) blood is to be collected for pharmacokinetic evaluation:

[0291] Day 13: Groups 3-7 animals 1-9 from each group.

[0292] Day 14, 1h post dosing: Groups 3-7 animals 1 , 2, 3 from each group.

[0293] Day 14, 4h post dosing: Groups 3-7 animals 4, 5, 6 from each group.

[0294] Day 14, 8h post dosing: Groups 3-7 animals 7, 8, 9 from each group.

[0295] Day 15, 24h post dosing: Groups 3-7 animals 1 , 2, 3 from each group.

[0296] Animals are to be bled via the retro-orbital sinus, whole blood is to be collected in NaF / EDTA Eppendorf tubes. The samples are to be centrifuged IMMEDIATELY post collection for 5 minutes at 3000 RPM. The 38 plasma is to be collected using filtered pipette tips and the vials containing the plasma will be IMMEDIATELY stored at -80°C.

[0297] Termination

[0298] At the end of the study (day 15), the animals will be euthanized by IP injection of 150-200 mg / kg pentobarbital sodium.

[0299] Results

[0300] The results of the performed von Frey test, according to the protocol indicated above, are shown in Figure 3. It is clear that the compound of the invention, (S,S)-(3-O-(propan-2-ol)-2-amino-prop-1-yl-4- hydroxybenzene (also referred to as M25), shows higher activity that its parent molecule (S,S)-2-N(3-O- (propan-2-ol)-1-propyl-4-hydroxybenzene)-3-phenylpropylamide (referred to as NRD) not only immediately after dosing, but seems to be showing a significant effect up to 24 hours post-dosing.

[0301] Body weight

[0302] Mean body weights of the animals in Groups 1-7 as measured on Day 0, Day 7 and Day 13 are shown in Table 4A; Table 4B and Figure 4 give the weights on Day 7 and Day 13 as % from baseline. All treated animals gained weight throughout the study. No statistically significant differences in the mean body weight between groups was seen.

[0303] 39

[0304] Pain sensitivity in von Frey Test

[0305] In the Von Frey test the withdrawal force response of the animals' injured paws was determined as a measure of mechanical pain sensitivity. Test results obtained at baseline (Day -1), after SNL surgery (Day 40

[0306] 13) and serially on Days 14 / 15 (1 , 4, 8, 24h post dosing) are presented for all groups in Table 5 (mean ± SEM).

[0307] Graphical representations are given in Figure 5A (all individual data); Figure 3 summarizes the results by test day and Figure 5B shows net response AUEC (vehicle response subtracted). The effect (Von Frey)- time course after the IV mid-dose M25 (Group 4) is compared to IP Gabapentin (Group 2) in Figure 50 and to PO NRD 80 mg / kg (Group 7) in Figure 5D.

[0308] As expected for the Von Frey model, all animals experienced higher sensitivity to the mechanical stimulation on study Day 13 compared to the baseline before surgery.; for example, vehicle-treated animals (Group 1): 3.20 ± 0.33 g on Day 13 vs. 26.00 ± 0.00 g at baseline; p<0.05. Treatment with Gabapentin IP (Group 2) resulted in a statistically significant increase in withdrawal force on testing Day 14, 1h and 4h post dosing, compared to the vehicle-treated animals (Group 1); for example, 1h post dosing, 17.80 ± 1.85 g vs. 3.20 ± 0.53 g; p<0.0001.

[0309] Treatment with an IV bolus dose of NRD (Group 3; 1.65 mg / kg), followed by an infusion of 4.08 mg / kg / 30min resulted in a statistically significantly increased withdrawal force on testing Day 14, 1h post 41 dosing (8.20 ± 2.99 g), compared to vehicle-treated animals (Group 1 ; 3.20 ± 0.53 g); p<0.05. Treatment with M25 IV at all doses (Groups 4, 5 and 6) resulted in a statistically significant increase in withdrawal force on testing Day 14, 1 h postdosing compared to the vehicle group. At the chosen doses, M25 appeared to be a more potent analgesic than NRD; the analgesic effect was similar at all M25 doses chosen.

[0310] The effect of M25, but not of IV NRD, persisted for several hours. Treatment with M25 at a dose level of 0.137 mg / kg bolus followed by an infusion of 1.69 mg / kg / 30min (Group 4) still resulted in a statistically significantly increased withdrawal force at 8h post dosing (8.20 ± 2.16 g), compared to vehicle-treated animals (Group 1 ; 2.80 ± 0.44 g); p<0.05. Even 24h after dosing, the withdrawal force appeared to be still increased, although the difference to the vehicle-group level did not reach statistical significance.

[0311] The analgesic effect of M25 was longer lasting than of the positive control Gabapentin (Figure 2C), with the result that the area under the effect curve (AUEC) of the net effect-time curve for M25 was at the mid dose at least as large as that for Gabapentin (Figure 5B).

[0312] No statistically significant differences between the NRD PO treated group (Group 7) and the vehicle- treated animals were seen at any time point, even though a slight positive response was seen in point estimates after the PO dose of NRD compared to the vehicle group (Figure 3, 5D).

[0313] Cold plate test

[0314] The thermal hyperalgesia response of all animals was determined by conducting the Cold Plate test. Testing was performed on the left paw. Test results obtained at baseline (Day -1), after SNL surgery (Day 13) and serially on Days 14 / 15 (1 , 4, 8, 24h post dosing) - always obtained immediately after the Von Frey test - are presented for all groups in Table 6 (mean ± SEM). Graphical representations are given in Figures 6A (all individual data), Figure 6B (by test day), and Figure 6C (net AUEC). The effect (Cold Plate)-time course after the IV mid-dose M25 (Group 4) is compared to IP Gabapentin (Group 2) in Figure 6D and to PO NRD 80 mg / kg (Group 7) in Figure 6E.

[0315] As expected for the Cold Plate model, all animals experienced higher sensitivity to the cold on study Day 13 compared to the baseline before surgery; for example, vehicle-treated animals (Group 1): 17.80 ± 2.37 sec vs. 29.50 ± 0.40 sec; p<0.05. Treatment with Gabapentin (Group 2), the positive control, resulted in a statistically significantly lower sensitivity to cold at all time points. 42

[0316] Compared to the treatment with the vehicle (Group 1), treatment with M25 at all dosing schemes tested resulted in statistically significantly decreased sensitivity to cold up to the last measurement, i.e., up to 24h post dosing at day 15; for example, on Day 14, 1 h post dosing, 25.60 ± 1.11 sec for the M25 vs. 16.40 + 1.80 sec for the vehicle group; p<0.001. No dependence of the reaction time to cold on the magnitude of the M25 dose could be discerned.

[0317] Similar to the Von Frey test, the effect of M25 in the Cold Plate test persisted for several hours. Treatment with M25 at the highest dose of 0.685 mg / kg bolus+infusion of 8.45 mg / kg / 30min (Group 5) or lowest dose of 0.027 mg / kg bolus+infusion of 0.338 mg / kg / 30min (Group 6) resulted in statistically significantly decreased sensitivity to cold on Day 14, 8h post dosing and on Day 15, 24h post dosing, compared to the vehicle-treated animals (Group 1): for example, on Day 14 8h post dosing, 24.40 ± 1.36 sec (Group 5) and 22.10 ± 1.72 sec (Group 6) vs. 13.80 ± 2.03 sec for the vehicle group; p<0.0001and p<0.001 respectively.

[0318] As in the Von Frey test, the analgesic effect of M25 measured in the Cold Plate test was longer lasting than of the positive control Gabapentin (Figure 6D), with the result that the area under the net effect-time curve (AUEC) for M25 was at the mid dose at least as large as that for Gabapentin (Figure 6C).

[0319] Treatment with NRD IV (Group 3) resulted in a statistically significantly lower sensitivity to cold only on Day 15, 24h post dosing (18.50 ± 1.57 sec), compared to the vehicle-treated animals (Group 1 ; 10.80 ± 1.01 sec); p<0.01.

[0320] Treatment with NRD via the PO route at a dose of 80 mg / kg (Group 7) resulted in a statistically significantly lower sensitivity to cold on Day 14, 8h post dosing (22.90 ± 1.46 sec) and on Day 15, 24h post dosing (21.80 ± 1.72 sec), compared to the vehicle-treated animals (Group 1 ; 13.80 ± 2.03 sec and 10.8 ± 1.01 sec respectively); p<0.001 and p<0.0001 respectively (Figures 6B, 6E).

[0321] Pharmacokinetics

[0322] Mean concentrations of NRD and M25 determined in Groups 3-7 over a 24-h time interval are listed in

[0323] Table 6.

[0324] Table 6. Mean concentration of M25 and NRD 43

[0325] Selected exposure parameters are compiled in Table 7.

[0326] NRD and M25 concentration-time profiles observed in animals treated with NRD and M25 are given in

[0327] Figures 7A and 7B respectively. The relationship between M25 IV dose administered and resulting exposure (AUC0-24h) is given graphically in Figure 7C.

[0328] Exposure to M25 (AUC0-24h) and resulting Von Frey effect (integrated over 24h) are depicted in Figure

[0329] 8.

[0330] Discussion 44

[0331] The current study was conducted to assess the analgesic effect of the NRD135S.E1 (NRD) and its metabolite M25 in the Spinal Nerve Ligation (SNL) rat model. Neuropathic pain was evaluated by the Von Frey test (mechanical allodynia) and the Cold Plate test (thermal hyperalgesia). The SNL model allows to study intensity of neuropathic pain and to evaluate potential therapeutic interventions. It involves ligating the lumbar segmental spinal nerve. The surgery focuses on the ventral ramus of the spinal nerve, leaving the dorsal ramus denervated.

[0332] In order to study the analgesic potency of the metabolite M25 formed from NRD after administration to animals and humans, M25 was administered intravenously at three different short (30-min) infusion levels preceded by an intravenous bolus dose to achieve concentrations spanning a 25-fold range. The mid dose targeted a concentration at the end of the infusion corresponding to the maximum concentrations putatively reached in a previous study in the SNL model where NRD had been given orally at an 80-mg / kg dose. No concentrations had been measured in this previous experiment, but based on the pharmacokinetic data collected during a rat mass balance study, Cmax for NRD and M25 could be estimated (Cmax, NRD = 2.03 pg / mL, Cmax,M25 = 0.84 pg / mL). Required bolus doses and infusion rates to approach these levels were calculated based on general pharmacokinetic principles and making best possible assumptions about the M25 disposition parameters. Five-fold lower and five-fold higher bolus / infusion combinations were additionally tested to counter uncertainties in parameter assumptions. Besides M25 administrations, NRD itself was also given intravenously (at a dose to reach previous levels) and orally (80 mg / kg). Gabapentin was used as a positive control for analgesic effects on neuropathic pain.

[0333] Rodents exhibit a paw withdrawal reflex when the paw is unexpectedly touched. The Touch Test™ Sensory Evaluator was used on the plantar surfaces of the rat's foot. The animal indicates sensation by pulling back its paw. The minimal force needed to elevate the withdrawal reflex is considered / designated as the value of reference. Decreases in force needed to induce withdrawal are indicative of allodynia, as the force applied is a non-painful stimulus under normal conditions. In the Von Frey test, treatment with an IV bolus dose of NRD (Group 3; 1.65 mg / kg), followed by an infusion (4.08 mg / kg / 30min) and the treatment with M25 IV at all doses (Groups 4, 5 and 6) resulted in a statistically significant increase in withdrawal force on testing Day 14, 1 h postdosing compared to the vehicle group. The effect of IV M25, but not of IV NRD, persisted for several hours. Treatment with M25 at a dose level of 0.137 mg / kg bolus followed by an infusion of 1.69 mg / kg / 30min (Group 4) resulted in a statistically significantly increased withdrawal force still at 8h post dosing. At the chosen doses, M25 appeared to be a more potent analgesic than NRD given IV. 45

[0334] In the Cold Plate test, treatment with M25 at mid-dose administration schemes teste resulted in statistically significant decreases in sensitivity to the cold up to the last measurement, i.e., up to 24h post dosing at day 15, .when compared to treatment with the vehicle (Groupl). Treatment with NRD via the PO route at a dose of 80 mg / kg (Group 7) and with all doses of M25 resulted in a statistically significantly lower sensitivity to cold on Day 14, 8h post dosing and on Day 15, 24h post dosing compared to the vehicle- treated animals. Treatment with NRD IV (Group 3) resulted in a statistically significantly lower sensitivity to cold only on Day 15, 24h post dosing (18.50 ± 1.57 sec), compared to the vehicle-treated animals.

[0335] Gabapentin clearly delivered the highest maximum analgesic effect of all compounds tested, with 17.8 g withdrawal force at 1h post dosing, followed by the M25 mid dose (10.9 g) and the M25 high dose (10.3 g). The same rank order in efficacy was seen in the Cold Plate test. However, the Gabapentin effect dissipated more rapidly than that of M25 with the result that at 8h and 24h post dosing the remaining analgesic effect was higher with M25 than with Gabapentin. When comparing the area under the net effect-time curve over 24h (vehicle effect subtracted) then the point estimate for the M25 mid-dose effect (Group 4) was larger than for Gabapentin. This was true for both effect tests, Von Frey and Cold Plate.

[0336] There was little difference in point estimates for maximum M25 efficacy between the three M25 dose levels. Differences became only apparent at later observation times. Even though M25 concentrations and AUG measures increased with increasing dose, reaching highest levels in Group 5 with the highest bolus / infusion rates, the magnitude of effects was higher at the mid dose (Group 4) than at the highest dose (Von Frey and Cold Plate). More detailed investigations would be needed to confirm and possibly explain this observation.

[0337] A comparison of point estimates for efficacy after NRD when given IV and PO showed higher efficacy for NRD IV than in the vehicle group only at the first measurement point (Von Frey, Cold Plate; no statistical comparison available); at 4h and beyond efficacy after NRD PO surpassed that of NRD IV. This pattern is compatible with formation of an active metabolite (M25) from parent drug during the absorption and disposition steps. M25 was measurable only after PO NRD, but not after IV NRD administration.

[0338] The pharmacokinetic information which can be derived from the present study is incomplete. Infusions were administered for 30 min, but for technical reasons the first sample for plasma concentration measurement could only be collected at 60 min. From a comparison of expected M25 concentrations at the end of a 30-min infusion and actual levels measured at 1h and beyond it becomes obvious that much 46 lower levels were observed than expected. Assumptions made in the estimation of M25 disposition parameters (distribution volume one fifth of that of NRD, clearances equal due to similar functionalities for metabolism) were obviously off from reality. Also, it has to be realized that the concentration-time profiles determined in the present study are composed from sampling different animals at each time point. However, observed parameter values for PO NRD were close to expectations, if the different absorption rate observed in the mass balance study (Tmax 0.5h; Cmax 2.03 pg / mL @ 80 mg / kg) and in the present study (4h; 0.589 pg / mL) are taken into account. Average NRD concentrations over the first 4 hours after administration corresponded well between the mass balance (0.56 pg / ml) and the present (0.353 pg / ml) study.

[0339] The concentration of M25 measured after PO NRD in the present study was lower than expected; M25 concentrations were only 1 / 1 Oth of values for NRD (MW adjusted), whereas earlier in the mass balance study in rats, the ratio was 1 / 2. The IV NRD bolus dose followed by a 30-min infusion generated unexpectedly low NRD concentrations and no measurable M25 concentrations. Average exposure over the first 4 hours post administration of 24.5 ng / ml were observed in the present study; in the rat mass balance study 91 .2 ng / ml had been observed after the bolus dose alone (dose adjusted). However, the condition between the two studies may not be entirely comparable. In the present study the rats had undergone complex surgical procedures prior to being administered test drug under isoflurane anesthesia.

[0340] Exposure to M25 concentrations after mid and high M25 IV doses was dose-proportional: the AUC1- 8h after the high dose was 4.99 times higher than for the 5 times lower mid dose. However, M25 levels for the low M25 dose were higher than expected. These levels may not be entirely reliable due to analytical limitations at the low concentrations observed. Nevertheless, there was a good linear relationship between M25 dose administered and AUC0-24h reached.

[0341] M25 concentrations were similar in the M25 IV low-dose (Group 6) and NRD PO (Group 7) groups. Even though in Group 7 additionally NRD levels were present, in the Von Frey test a statistically significant effect over the vehicle group was only seen for the M25 low dose group (1 h post dosing), but not for the NRD PO group. In the Cold Plate test similar effects were seen in the two groups at 8h and 24h post dosing.

[0342] Conclusion 47

[0343] In the Von Frey test, treatment by IV bolus followed by an infusion with NRD and M25 (at all tested doses) effectively reduced neuropathic pain as was detected by the increase in withdrawal force 1h post dosing on study Day 14. M25, at a dose of 0.137 mg / kg IV bolus followed by 1.69 mg / kg / 30min infusion, statistically significantly reduced pain sensitivity still at 8h post dosing at Day 14 in contrast to NRD given at the chosen bolus injection followed by 30-min infusion doses. No statistically significant effects were observed in the NRD PO treated group (Group 7).

[0344] Overall, after bolus injection followed by a 30-min infusion M25 appeared to be a more potent analgesic at all doses tested than NRD after iv bolus injection.

[0345] In the Cold Plate test, treatment with M25 at all dosing schemes tested resulted in statistically significant increases in withdrawal force up to the last measurement, i.e., up to 24h post dosing at Day 15 compared to the treatment with the vehicle (Group 1 ). Oral treatment with NRD at a dose of 80 mg / kg were effective in the Cold Plate test on Day 14 (8h post dosing) and on Day 15 (24h post dosing). Treatment with NRD IV bolus followed by a 30-min infusion showed efficacy only at 24h post dosing.

Claims

1. CLAIMS1. A compound of formula (I):or a pharmaceutically acceptable salt thereof, whereinX is selected from -O-, -CH2O- -CH2CH2O-, -CH(CH3)CH2O- and -CH2C(CH3)O-;Zn is selected from -(CH2CH2O)n-, -(CH(CH3)CH2O)n- and -(CH2C(CH3)O)n-; n is an integer from 1 to 50; andR is selected from -H, and -OH.

2. The compound of claim 1 , wherein X is -CH2O- or -CH2CH2O-.

3. The compound of claim 2, wherein X is -CH2O-.

4. The compound of any one of claims 1 to 3, wherein Znis -(CH2C(CH3)O)n-5. The compound of any one of claims 1 to 4, wherein n is an integer from 1 to 10.

6. The compound of any one of claims 1 to 5, wherein n is 1.

7. The compound of any one of claims 1 to 6, wherein Znis8. The compound of any one of claims 1 to 7, wherein R is -OH.

9. The compound of any one of claims 1 to 8, wherein the compound is a compound of formula (le):or a pharmaceutically acceptable salt thereof.

10. A pharmaceutical composition comprising the compound of any one of claims 1 to 9 and a pharmaceutically acceptable carrier.

11. The compound of any one of claims 1 to 9 or the pharmaceutical composition of claim 10 for use as a medicament.

12. The compound of any one of claims 1 to 9 or the pharmaceutical composition of claim 10 for use in the treatment or prevention of pain.

13. The compound for use of claim 12 or the pharmaceutical composition for use of claim 12, wherein the pain is acute pain, chronic pain, nociceptive pain, cutaneous pain, somatic pain, myofascial pain, visceral pain, phantom limb pain, neuropathic pain, headaches or migraine.

14. The compound of any one of claims 1 to 9 or the pharmaceutical composition of claim 10 for use in the treatment or prevention of inflammation.

15. The compound of any one of claims 1 to 9 or the pharmaceutical composition of claim 10 for use in the treatment or prevention of autoimmune disease, preferably wherein the autoimmune diseaseis celiac disease, diabetes mellitus type 1, sarcoidosis, systemic lupus erythematosus (SLE), Sjogren's syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM), ulcerative colitis (UC) or multiple sclerosis (MS)

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