Pharmaceutical compositions for the treatment of pain

1. A composition for treating pain in a patient, the composition comprising:

(i) a nicotinic acetylcholine receptor ligand; and

(ii) a nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator in admixture with at least one pharmaceutically acceptable excipient, wherein the nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator is a compound of formula (II):

or a pharmaceutically acceptable salt thereof, wherein:

Ar 2 is pyridazinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl,

Ar 3 is aryl, pyridazinyl, pyridinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl, and

Ar 2 and Ar 3 are substituted independently with 0, 1, 2, 3, or 4 substituents independently selected from the group consisting of alkoxy, alkoxycarbonyl, alkoxycarbonylamino, alkoxycarbonylaminalkyl, alkyl, alkylamino, alkylcarbonyl, alkylslfonyl, amino, aminoalkyl, carboxy, dialkylamino, dialkylaminoalkyl, halo, haloalkyl, haloalkylcarbonyl, heteroaryl, heterocycle, hydroxyl, hydroxyalkyl, cyano, nitro, oxo, sulfonamide and dialkylsulfonylformimidamide.

2. The composition of claim 1 , wherein the nicotinic acetylcholine receptor ligand is a nicotinic acetylcholine receptor subtype α4β2 ligand demonstrating a K i value of about 0.001 nanomolar to about 100 micromolar, as measured by [ 3 H]-cytisine binding assay (K i Cyt).

3. The composition of claim 1 , wherein the nicotinic acetylcholine receptor ligand is a nicotinic acetylcholine receptor subtype α4β2 agonist or partial agonist.

4. The composition of claim 1 , wherein the nicotinic acetylcholine receptor ligand is a compound selected from:

5-[(2R)-azetidin-2-ylmethoxy]-2-chloropyridine;

(3R)-1-pyridin-3-ylpyrrolidin-3-amine;

2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine;

3-(5,6-dichloro-pyridin-3-yl)-1(S),5(S)-3,6-diazabicyclo[3.2.0]heptane; and

(R,R)-1-(pyridin-3-yl)octahydro-pyrrolo[3,4-b]pyrrole;

or is a pharmaceutically acceptable salt thereof.

5. A composition for treating pain in a patient, the composition comprising:

(i) a nicotinic acetylcholine receptor ligand; and

(ii) a nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator in admixture with at least one pharmaceutically acceptable excipient, wherein the nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator is selected from the group consisting of:

5-(2,3-difluorophenyl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

5-(pyridin-3-yl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

2-fluoro-N,N-dimethyl-4-(3-(pyrimidin-5-yl)-1,2,4-oxadiazol-5-yl)aniline;

3-(3-(pyrimidin-5-yl)-1,2,4-oxadiazol-5-yl)benzonitrile;

5-(3,4-difluorophenyl)-3-(pyridazin-4-yl)-1,2,4-oxadiazole;

3-(pyridazin-4-yl)-5-(pyridin-3-yl)-1,2,4-oxadiazole;

N,N-dimethyl-N′-(4-(3-(pyrimidin-5-yl)-1,2,4-oxadiazol-5-yl)phenylsulfonyl)formimidamide;

5-(4-fluorophenyl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

5-(3-fluorophenyl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

3-(pyrimidin-5-yl)-5-(3,4,5-trifluorophenyl)-1,2,4-oxadiazole;

5-(2-chloropyridin-4-yl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

3-(Pyridin-3-yl)-5-(pyrimidin-5-yl)-1,2,4-oxadiazole;

5-(Pyridazin-4-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

3-(3-(pyridazin-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile;

5-(3-fluorophenyl)-3-(pyridazin-4-yl)-1,2,4-oxadiazole;

3-(pyridazin-4-yl)-5-(3,4,5-trifluorophenyl)-1,2,4-oxadiazole;

5-(3,5-difluorophenyl)-3-(pyridazin-4-yl)-1,2,4-oxadiazole;

5-(4-fluorophenyl)-3-(pyridazin-4-yl)-1,2,4-oxadiazole;

3-(pyridazin-4-yl)-5-(pyrimidin-5-yl)-1,2,4-oxadiazole;

3-(pyridazin-4-yl)-5-(2,3,6-trifluorophenyl)-1,2,4-oxadiazole;

3-(pyridazin-4-yl)-5-(2,3,4-trifluorophenyl)-1,2,4-oxadiazole;

N,N-dimethyl-N′-(4-(3-(pyridazin-4-yl)-1,2,4-oxadiazol-5yl)phenylsulfonyl)formimidamide;

5-(3,4-difluorophenyl)-3-(pyrimidin-5-yl)-1,2,4-oxadiazole;

3-(3,4-difluorophenyl)-5-(pyrimidin-5-yl)-1,2,4-oxadiazole;

3-(pyrimidin-5-yl)-5-(2,3,4-trifluorophenyl)-1,2,4-oxadiazole;

3-(pyrimidin-5-yl)-5-(2,3,6-trifluorophenyl)-1,2,4-oxadiazole;

3-(pyrimidin-5-yl)-5-(2,3,4,5-tetrafluorophenyl)-1,2,4-oxadiazole;

5-(imidazo[1,5-a]pyridin-6-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(1H-indol-6-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(2,7-dimethylpyrazolo[1,5-a]pyrimidin-6-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(2-methylbenzofuran-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(benzo[d][1,2,3]thiadiazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(1H-benzo[d]imidazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(1H-benzo[d][1,2,3]triazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(benzo[d]thiazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

3-(pyridin-3-yl)-5-(1H-pyrrolo[2,3-b]pyridin-5-yl)-1,2,4-oxadiazole;

5-(1H-indol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(benzofuran-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(1-methyl-1H-benzo[d]imidazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

3-(imidazo[1,2-a]pyridin-6-yl)-5-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(6-chloropyridin-3-yl)-3-(imidazo[1,2-a]pyridin-6-yl)-1,2,4-oxadiazole;

5-(6-fluoropyridin-3-yl)-3-(imidazo[1,2-a]pyridin-6-yl)-1,2,4-oxadiazole;

5-(5-fluoropyridin-3-yl)-3-(imidazo[1,2-a]pyridin-6-yl)-1,2,4-oxadiazole;

5-(1H-indazol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-([1,2,4]triazolo[4,3-a]pyridin-6-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

5-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)benzo[d]oxazol-2(3H)-one;

5-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)-1H-benzo[d]imidazole-2(3H)-thione;

1,3-dimethyl-5-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)-1H-benzo[d]imidazol-2(3H)-one;

6-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)benzo[d]oxazol-2(3H)-one;

5-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)-1H-benzo[d]imidazol-2(3H)-one;

6-(3-(Pyridin-3-yl)-1,2,4-oxadiazol-5-yl)benzo[d]oxazol-2-amine;

6-(3-(pyridin-3-yl)-1,2,4-oxadiazol-5-yl)benzo[d]oxazole;

5-(5-(pyridin-3-yl)-1,2,4-oxadiazol-3-yl)benzo[d]oxazol-2(3H)-one;

5-(5-(6-chloropyridin-3-yl)-1,2,4-oxadiazol-3-yl)benzo[d]oxazol-2(3H)-one; and

5-(benzo[d][1,3]dioxol-5-yl)-3-(pyridin-3-yl)-1,2,4-oxadiazole;

or a pharmaceutically acceptable salt thereof.

6. The composition of claim 1 , further comprising an effective amount of at least one of a non-steroid anti-inflammatory agent and an opioid.

7. A pharmaceutical composition comprising a therapeutically effective amount of a composition of claim 1 and a pharmaceutically acceptable carrier or excipient.

8. A method for treating a mammalian subject suffering from a pain condition, the method comprising administering a therapeutically effective amount of the composition of claim 1 , wherein the pain condition is nociceptive pain, neuropathic pain or a combination thereof.

9. A method for treating a pain condition comprising administering a therapeutically effective amount of the composition of claim 8 , wherein the nociceptive pain is selected from post-operative pain, osteoarthritis pain, rheumatoid arthritis pain, musculoskeletal pain, burn pain, ocular pain, pain due to inflammation and bone fracture.

10. An article of manufacture for the treatment of pain, comprising:

(i) a first pharmaceutical dosage form comprising at least one nicotinic acetylcholine receptor ligand; and

(ii) a second pharmaceutical dosage form comprising at least nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator; wherein the article contains first and second pharmaceutical dosage forms wherein the nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator is a compound of formula (II):

or a pharmaceutically acceptable salt thereof, wherein:

Ar 2 is pyridazinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl,

Ar 3 is aryl, pyridazinyl, pyridinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl, and

Ar 2 and Ar 3 are substituted independently with 0, 1, 2, 3, or 4 substituents independently selected from the group consisting of alkoxy, alkoxycarbonyl, alkoxycarbonylamino, alkoxycarbonylaminalkyl, alkyl, alkylamino, alkylcarbonyl, alkylslfonyl, amino, aminoalkyl, carboxy, dialkylamino, dialkylaminoalkyl, halo, haloalkyl, haloalkylcarbonyl, heteroaryl, heterocycle, hydroxyl, hydroxyalkyl, cyano, nitro, oxo, sulfonamide and dialkylsulfonylformimidamide.

11. A composition for treating pain in a patient, the composition comprising:

(i) a nicotinic acetylcholine receptor ligand; and

(ii) a nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator in admixture with at least one pharmaceutically acceptable excipient, wherein the nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator is a compound of formula (II):

or a pharmaceutically acceptable salt thereof, wherein:

Ar 2 is aryl or pyridinyl,

Ar 3 is pyridazinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl, and

Ar 2 and Ar 3 are substituted independently with 0, 1, 2, 3, or 4 substituents independently selected from the group consisting of alkoxy, alkoxycarbonyl, alkoxycarbonylamino, alkoxycarbonylaminalkyl, alkyl, alkylamino, alkylcarbonyl, alkylslfonyl, amino, aminoalkyl, carboxy, dialkylamino, dialkylaminoalkyl, halo, haloalkyl, haloalkylcarbonyl, heteroaryl, heterocycle, hydroxyl, hydroxyalkyl, cyano, nitro, oxo, sulfonamide and dialkylsulfonylformimidamide.

12. The composition of claim 11 , wherein the nicotinic acetylcholine receptor ligand is a nicotinic acetylcholine receptor subtype α4β2 ligand demonstrating a K i value of about 0.001 nanomolar to about 100 micromolar, as measured by [ 3 H]-cytisine binding assay (K i Cyt).

13. The composition of claim 11 , wherein the nicotinic acetylcholine receptor ligand is a nicotinic acetylcholine receptor subtype α4β2 agonist or partial agonist.

14. The composition of claim 11 , wherein the nicotinic acetylcholine receptor ligand is a compound selected from:

5-[(2R)-azetidin-2-ylmethoxy]-2-chloropyridine;

(3R)-1-pyridin-3-ylpyrrolidin-3-amine;

2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine;

3-(5,6-dichloro-pyridin-3-yl)-1(S),5(S)-3,6-diazabicyclo[3.2.0]heptane; and

(R,R)-1-(pyridin-3-yl)octahydro-pyrrolo[3,4-b]pyrrole;

or is a pharmaceutically acceptable salt thereof.

15. The composition of claim 11 , further comprising an effective amount of at least one of a non-steroid anti-inflammatory agent and an opioid.

16. A pharmaceutical composition comprising a therapeutically effective amount of a composition of claim 11 and a pharmaceutically acceptable carrier or excipient.

17. An article of manufacture for the treatment of pain, comprising:

(i) a first pharmaceutical dosage form comprising at least one nicotinic acetylcholine receptor ligand; and

(ii) a second pharmaceutical dosage form comprising at least nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator; wherein the article contains first and second pharmaceutical dosage forms wherein the nicotinic acetylcholine receptor subtype α4β2 positive allosteric modulator is a compound of formula (II):

or a pharmaceutically acceptable salt thereof, wherein:

Ar 2 is aryl or pyridinyl,

Ar 3 is pyridazinyl, pyrimidinyl, triazinyl, or bicyclic heteroaryl, and

Ar 2 and Ar 3 are substituted independently with 0, 1, 2, 3, or 4 substituents independently selected from the group consisting of alkoxy, alkoxycarbonyl, alkoxycarbonylamino, alkoxycarbonylaminalkyl, alkyl, alkylamino, alkylcarbonyl, alkylslfonyl, amino, aminoalkyl, carboxy, dialkylamino, dialkylaminoalkyl, halo, haloalkyl, haloalkylcarbonyl, heteroaryl, heterocycle, hydroxyl, hydroxyalkyl, cyano, nitro, oxo, sulfonamide and dialkylsulfonylformimidamide.