Antitussive compositions comprising memantine

1. An antitussive oral lozenge comprising:

about 6-35 mg of memantine, or a pharmaceutically acceptable salt thereof;

menthol;

an alkalinizing agent comprising sodium carbonate and sodium bicarbonate at a weight ratio of about 1:1 to about 1:10, in an amount sufficient to raise the pH of the oral cavity, after buccal or sublingual administration, to a pH of 7.8 or higher for at least about 2 minutes; and

one or more excipients selected from the group consisting of a binder, one or more sugar or sugar substitutes, a filler, a disintegrant, a lubricant, and combinations thereof;

wherein after a single buccal or sublingual administration to a patient, said oral lozenge provides:

i) a memantine T max ranging from about 15 minutes to about 5.5 hours;

ii) a memantine C max ranging from about 1 ng/mL to about 2.5 ng/mL per mg dosed;

iii) a memantine AUC 0-∞ ranging from about 600 ng-hr/mL to about 5,000 ng-hr/mL and;

iv) an absorption rate of memantine that is higher than the absorption rate of said composition that does not include an alkalinizing agent.

2. The antitussive oral lozenge of claim 1 , wherein the buccal permeability of memantine is about 3.5×10 −7 cm/sec to about 8.25×10 −6 cm/sec , when tested ex vivo in porcine buccal mucosa.

3. The antitussive oral lozenge of claim 1 , wherein the excipients comprise microcrystalline cellulose, magnesium stearate, starch and mannitol.

4. The antitussive oral lozenge of claim 1 , wherein the lozenge is substantially free of pharmaceutically active ingredients other than memantine and menthol.

5. The antitussive oral lozenge of claim 1 , further comprising one or more additional pharmaceutically active ingredients selected from the group consisting of antitussives other than memantine, expectorants, mucolytics, decongestants, nasal decongestants, first generation antihistamines, antihistamines, opioid analgesics, non-opiate analgesics, antipyretics, and combinations thereof.

6. The antitussive oral lozenge of claim 5 , wherein the one or more additional pharmaceutically active ingredients are selected from the group consisting of guaifenesin, ambroxol, a first generation antihistamine, and combinations thereof.

7. The antitussive oral lozenge of claim 6 , wherein the one or more additional pharmaceutically active ingredients comprise a first generation antihistamine.

8. The antitussive oral lozenge of claim 1 , wherein the total weight of the lozenge is up to about 2.8 grams.

9. A method of treating cough, comprising administering the antitussive lozenge of claim 1 to the oral cavity of a patient in need thereof.

10. A method of treating cough of claim 9 , wherein the oral administration is buccal administration.

11. A method of treating cough of claim 9 , wherein the oral administration is sublingual administration.

12. The method of treating cough of claim 9 , wherein the memantine dose is about 0.01-0.5 mg/kg.

13. The antitussive oral lozenge of claim 1 , wherein after a buccal or sublingual single administration to a patient, said oral lozenge provides: a memantine T max ranging from about 15 minutes to about 1.5 hours.

14. The antitussive oral lozenge of claim 1 , wherein after a buccal or sublingual single administration to a patient, said oral lozenge provides: a memantine T max ranging from about 1.5 hours to about 5.5 hours.

15. The antitussive oral lozenge of claim 1 , wherein after a buccal or sublingual single administration to a patient, said oral lozenge provides: a memantine T max ranging from about 15 minutes to about 3 hours.

16. The antitussive oral lozenge of claim 1 , wherein said antitussive lozenge further provides a buccal permeability rate of memantine that is higher than the buccal permeability rate of said lozenge that does not include an alkalinizing agent.