Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K31/00—Medicinal preparations containing organic active ingredients
  • A61K31/185—Acids; Anhydrides, halides or salts thereof, e.g. sulfur acids, imidic, hydrazonic or hydroximic acids
  • A61K31/19—Carboxylic acids, e.g. valproic acid
  • A61K31/195—Carboxylic acids, e.g. valproic acid having an amino group
  • A61K31/197—Carboxylic acids, e.g. valproic acid having an amino group the amino and the carboxyl groups being attached to the same acyclic carbon chain, e.g. gamma-aminobutyric acid [GABA], beta-alanine, epsilon-aminocaproic acid or pantothenic acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P23/00—Anaesthetics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/04—Centrally acting analgesics, e.g. opioids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]

Definitions

• the present invention is the use of analogs of giutamic acid and gamma- aminobutyric acid (GABA) in pain therapy, as the compounds exhibit analgesic/antihyperalgesic action.
• GABA gamma- aminobutyric acid
• the compounds of the invention are known agents useful in antiseizure therapy for central nervous system disorders such as epilepsy, Huntington's chorea, cerebral ischemia, Parkinson's disease, tardive dyskinesia, and spasticity. It has also been suggested that the compounds can be used as antidepressants, anxiolytics, and antipsychotics. See WO 92/09560 (United States Serial Number 618,692 filed November 27, 1990) and WP 93/23383 (United States Serial Number 886,080 filed May 20, 1992).
• the instant invention is a method of using a compound of Formula I below in the treatment of pain, especially for treatment of chronic pain disorders.
• disorders include, but are not limited to, inflammatory pain, postoperative pain, osteoarthritis pain associated with metastatic cancer, trigeminal neuralgia, acute herpetic and postherpetic neuralgia, diabetic neuropathy, causalgia, brachial plexus avulsion, occipital neuralgia, reflex sympathetic dystrophy, fibromyalgia, gout, phantom limb pain, burn pain, and other forms of neuralgic, neuropathic, and idiopathic pain syndromes.
• a compound are those of Formula I
• Rj is a straight or branched alkyl of from 1 to 6 carbon atoms, phenyl, or cycloalkyl of from 3 to 6 carbon atoms;
• R 2 is hydrogen or methyl;
• R3 is hydrogen, methyl, or carboxyl.
• Diastereomers and enantiomers of compounds of Formula I are included in the invention.
• Preferred compounds of the invention are those according to Claim 1 wherein R3 and R 2 are hydrogen, and Rj is -(CH ) ⁇ - 2 -i C4H9 as an (R), (S), or
• the more preferred compounds of the invention are (S)-3-(aminomethyl)- 5-methylhexanoic acid and 3-aminomethyl-5-methyl-hexanoic acid.
• CI-1008 ((S)-3-(aminomethyl)-5-methylhexanoic acid), and 3-aminomethyl-5-methyl-hexanoic acid in the Rat Paw Formalin Test Test compounds were administered s.c. 1 hour before an intraplantar injection of 50 ⁇ L formalin. The time spent licking/biting the injected paw during the early and late phases was scored. Results are shown as the mean ⁇ SEM of 6 to
• Hyperalgesia Nociceptive thermal thresholds were measured in the rat using the Hargreaves apparatus. Baseline (BL) measurements were taken before animals were administered with 100 ⁇ L of 2% carrageenin by intraplantar injection. Results are shown as mean ( ⁇ SEM) of 8 animals per group. Gabapentin (GP) or
• CI-1008 was administered s.c. 2.5 hours after carrageenin. *P ⁇ 0.05 and **P ⁇ 0.01 significantly different from vehicle control group at the same time point (ANOVA followed by Dunnett's t-test).
• Gabapentin or S-(+)-3 isobutylgaba was administered 1 hour before surgery. Morphine was administered 0.5 hour before surgery.
• Thermal paw withdrawal latencies (PWL) were determined for both ipsilateral and contralateral paws using the rat plantar test. For clarity contralateral paw data for drug-treated animals is not shown.
• Baseline (BL) measurements were taken before surgery and
• PWL were reassessed 2, 24, 48, and 72 hours postsurgery. Results are expressed as the mean PWL(s) of 8 to 10 animals per group (vertical bars reperesent ⁇ SEM). *P ⁇ 0.05 **P ⁇ 0.01 significantly different (ANOVA followed by Dunnett's t-test), comparing ipsilateral paw of drug-treated groups to ispsilateral paw of vehicle-treated group at each time point.
• -•- is vehicle contralateral
• -O- vehicle ispsilateral
• - ⁇ - is 1 mg/kg morphine
• -D- is 3
• -O- is 6 for morphine in 4a.
• Gabapentin or S-(+)-3- ⁇ sobutylgaba was administered 1 hour before surgery
• Morphine was administered 0.5 hour before surgery
• Paw withdrawal thresholds to von Frey hair filaments were determined for both ipsilateral and contralateral paws.
• Baseline (BL) measurements were taken before surgery, and withdrawal thresholds were reassessed 3, 25, 49, and 73 hours postsurgery Results are expressed as median force (g) required to induce a withdrawal of paw in 8 to 10 animals per group (vertical bars represent first and third quartiles) *P ⁇ 0.05 significantly different (Mann Whitney t-test) comparing ipsilateral paw of drug-treated groups to ipsilateral paw of vehicle treated group at each time point.
• -•- is vehicle contralateral
• -O- is vehicle ispsilateral
• For morphine (5a), - ⁇ - is 1 mg/kg, -D- is 3, and -0- is 16
• the instant invention is a method of using a compound of Formula I above as an analgesic in the treatment of pain as listed above Pain such as inflammatory pain, neuropathic pain, cancer pain, postoperative pain, and ldiopathic pain which is pain of unknown origin, for example, phantom limb pain are included especially Neuropathic pain is caused by injury or infection of peripheral sensory nerves It includes, but is not limited to pain from peripheral nerve trauma, herpes virus infection, diabetes mel tus, causalgia, plexus avulsion, neuroma, limb amputation, and vasculitis Neuropathic pain is also caused by nerve damage from chronic alcoholism, human immunodeficiency virus infection, hypothyroidism, uremia, or vitamin deficiencies.
• Neuropathic pain includes, but is not limited to pain caused by nerve injury such as, for example, the pain diabetics suffer from The conditions listed above are known to be poorly treated by currently marketed analgesics such as narcotics or nonsteroidal an ti -inflammatory drugs (NSAID) due to insufficient efficacy or limiting side effects
• analgesics such as narcotics or nonsteroidal an ti -inflammatory drugs (NSAID) due to insufficient efficacy or limiting side effects
• alkyl which term is methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, isopentyl, and neopentyl, as well as those as would occur to one skilled in the art.
• cycloalkyl is exemplified by cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl
• the compounds of the present invention may form pharmaceutically acceptable salts with both organic and inorganic acids or bases.
• the acid addition salts of the basic compounds are prepared either by dissolving the free base in aqueous or aqueous alcohol solution or other suitable solvents containing the appropriate acid and isolating the salt by evaporating the solution.
• pharmaceutically acceptable salts are hydrochlorides, hydrobromides, hydrosulfates, etc. as well as sodium, potassium, and magnesium, etc. salts.
• the compounds of the present invention can contain one or several asymmetric carbon atoms.
• the invention includes the individual diastereomers or enantiomers, and the mixtures thereof.
• the individual diastereomers or enantiomers may be prepared or isolated by methods already well-known in the art.
• the method for the formation of the 3-alkyl-4-aminobutanoic acids starting from 2-alkenoic esters is prepared from commercially available aldehydes and monoethyl malonate by the Knoevenagel reaction (Kim Y.C., Cocolase G.H., J. Med. Chem., 1965:8509), with the exception of ethyl 4,4-dimethyl-2- pentenoate.
• This compound was prepared from 2,2-dimethylpropanal and ethyl lithioacetate, followed by dehydration of the ⁇ -hydroxyester with phosphoryl chloride and pyridine.
• the synthetic sequence was initiated with the corresponding alcohol, which was oxidized to the aldehyde by the method of Corey, etal., Tetrahedrom. Lett.. 1975:2647-2650.
• the compounds made by the synthetic methods can be used as pharmaceutical compositions as agent in the treatment of pain when an effective amount of a compound of the Formula I, together with a pharmaceutically acceptable carrier is used.
• the pharmaceutical can be used in a method for treating such disorders in mammals, including human, suffering therefrom by administering to such mammals an effective amount of the compound as described above in unit dosage form.
• the pharmaceutical compound made in accordance with the present invention, can be prepared and administered in a wide variety of dosage forms by either oral or parenteral routes of administration.
• these pharmaceutical compositions can be made in inert, pharmaceutically acceptable carriers which are either solid or liquid.
• Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, and suppositories.
• Other solid and liquid form preparations could be made in accordance with known methods of the art and administered by the oral route in an appropriate formulation, or by a parenteral route such as intravenous, intramuscular, or subcutaneous injection as a liquid formulation.
• the quantity of active compound in a unit dose of preparation may be varied or adjusted from 1 mg to about 300 mg/kg daily, based on an average 70-kg patient. A daily dose range of about 1 mg to about 50 mg/kg is preferred. The dosages, however, may be varied depending upon the requirement with a patient, the severity of the condition being treated, and the compound being employed.
• Sprague-Dawley 70-90 g were administered with 100 ⁇ L of 2% carrageenin by intraplantar injection into the right hind paw. Animals were dosed with the test drug after development of peak hyperalgesia. Separate groups of animals were used for the mechanical and thermal hyperalgesia studies.
• Nociceptive pressure thresholds were measured in the rat paw pressure test using an analgesimeter (Ugo Basile). A cut-off point of 250 g was used to prevent any damage to the paw. The intraplantar injection of carrageenin produced a reduction in the nociceptive pressure threshold between 3 and 5 hours after injection, indicating induction of hyperalgesia. Morphine (3 mg/kg, s.c.) produced a complete blockade of hyperalgesia ( Figure 2). Gabapentin (3-300 mg/kg, s.c.) and CI-1008 (1-100 mg/kg, s.c.) dose-dependently antagonized the hyperalgesia, with respective MED of 10 and 3 mg/kg ( Figure 2). B. Thermal Hyperalgesia
• the assay of Bennett G.J. provides an animal model of a peripheral mononeuropathy in rat that produces disorder of pain sensation like those seen in man (Pain. 1988;33:87-107).
• mice Male Sprague-Dawley rats (250-300 g), obtained from Bantin and Kingmen, (Hull, U.K.) were used in all experiments. Before surgery, animals were housed in groups of 6 under a 12-hour light/dark cycle (lights on at 07 hour 00 minute) with food and water ad libitum. Postoperatively, animals were housed in pairs on "Aqua-sorb" bedding consisting of air laid cellulose (Beta Medical and Scientific, Sale, U.K.) under the same conditions. All experiments were carried out by an observer blind to drug treatments.
• Animals were anaesthetized with 2% isofluorane and 1.4 O 2 /NO 2 mixture which was maintained during surgery via a nose cone.
• the plantar surface of the right hind paw was prepared with 50% ethanol, and a 1-cm longitudinal incision was made through skin and fascia, starting 0.5 cm from the edge of the heel and extending towards the toes.
• the plantaris muscle was elevated using forceps and incised longitudinally.
• the wound was closed using two simple sutures of braided silk with a FST-02 needle.
• the wound site was covered with Terramycin spray and Auromycin powder. Postoperatively, none of the animals displayed any signs of infection with the wounds healing well after 24 hours. The sutures were removed after 48 hours.
• Tactile allodynia was measured using Semmes-Weinstein von Frey hairs (Stoelting, Illinois, U.S.A.). Animals were placed into wire-mesh-bottom cages allowing access to the underside of their paws. The animals were habituated to this environment prior to the start of the experiment. Tactile allodynia was tested by touching the plantar surface of the animals hind paw with von Frey hairs in ascending order of force (0.7, 1.2, 1.5, 2, 3.6, 5.5, 8.5, 11.8, 15.1, and 29 g) until a paw withdrawal response was elicited. Each von Frey hair was applied to the paw for 6 seconds, or until a response occurred.
• morphine (6 mg, s.c.) increased PWL of the contralateral paw in the thermal hyperalgesia test (data not shown).
• the results presented here show that incision of the rat plantaris muscle induces thermal hyperalgesia and tactile allodynia lasting at least 3 days.
• the major findings of the present study are that gabapentin and S-(+)-3-isobutylgaba are equally effective at blocking both nociceptive responses.
• morphine was found to be more effective against thermal hyperalgesia than tactile allodynia.
• S-(+)-3-isobutylgaba completely blocked induction and maintenance of allodynia and hyperalgesia.

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• 1997
  • 1997-07-16 KR KR10-1999-7000577A patent/KR100491282B1/ko not_active Expired - Lifetime
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