Details for Patent: 7,026,508

Title:	Succinate salt of O-desmethyl-venlafaxine
Abstract:	A novel salt of O-desmethyl venlafaxine is provided, O-desmethylvenlafaxine succinate. Pharmaceutical compositions, dosage forms and methods of use are also provided.
Inventor(s):	Winkley; Michael W. (Campbell Hall, NY), Sutherland; Karen W. (New City, NY)
Assignee:	Wyeth (Madison, NJ)
Filing Date:	Nov 10, 2004
Application Number:	10/985,292
Claims:	1. A method of preparing O-desmethyl-venlafaxine comprising the step of demethylating venlafaxine or a salt thereof with an alkali metal salt of a trialkyl borohydride. 2. The method of claim 1, wherein each alkyl group in the trialkyl borohydride is independently a C.sub.1 C.sub.6 alkyl. 3. The method of claim 2, wherein the alkali metal salt of a trialkyl borohydride is selected from L-selectride, K-selectride, lithium triethylborohydride, potassium triethylborohydride, and mixtures thereof. 4. The method of claim 3, wherein the alkali metal salt of a trialkyl borohydride is L-selectride. 5. The method of claim 1, wherein the demethylation step is performed at a temperature of from about 60 to about 140.degree. C. 6. The method of claim 1, further comprising the step of converting the O-desmethyl-venlafaxine to O-desmethyl-venlafaxine succinate. 7. The method of claim 1, further comprising the step of deactivating any boron containing byproducts produced by the demethylation reaction. 8. The method of claim 7, wherein the deactivating step comprises oxidizing the boron containing byproducts. 9. The method of claim 8, wherein the oxidizing step comprises reacting the boron containing byproducts with an oxidizing agent selected from hydrogen peroxide, sodium perborate, and mixtures thereof. 10. The method of claim 8, wherein the oxidizing step comprises adding the boron containing byproducts to an oxidizing agent or a solution comprising an oxidizing agent. 11. A method of preparing O-desmethyl-venlafaxine comprising the steps of: (a) demethylating venlafaxine or a salt thereof with an alkali metal salt of a trialkyl borohydride to yield an alkali metal salt of O-desmethyl-venlafaxine; and (b) converting the alkali metal salt of O-desmethyl-venlafaxine to the free base of O-desmethyl-venlafaxine. 12. The method of claim 11, wherein step (b) comprises neutralizing the alkali metal salt of O-desmethyl-venlafaxine with acid. 13. The method of claim 11, further comprising the step of (c) converting the free base of O-desmethyl-venlafaxine to O-desmethyl-venlafaxine succinate. 14. The method of claim 11, wherein the venlafaxine in step (a) is the free base of venlafaxine. 15. The method of claim 1 wherein the demethylation step is performed at about 90.degree. C. 16. The method of claim 1 wherein the demethylation step is performed with 5.5 molar excess of trialkyl borohydride.