Patent ID: 6909004

Claim:
A method of purifying lansoprazole to obtain lansoprazole having less than about 0.1%, wt/wt, water comprising the steps of: a) providing a solution of lansoprazole in a solvent selected from an organic solvent or a mixture of organic solvent and water in the presence of an amine compound, wherein the amine compound is present at a ratio of about 1:1, mole:mole, relative to lansoprazole; b) combining the provided solution with an acid; c) isolating the lansoprazole; d) dissolving the isolated lansoprazole in an organic solvent selected from the group consisting of acetone, 2-butanone, methanol, dimethyl-carbonate, and diethyl-carbonate; and e) isolating the purified lansoprazole having less than about 0.1%, wt/wt, water.