US Patent 7947840 Process for preparation of enantiomerically pure esomeprazole

The present invention provides an improved and commercially viable process for preparation of substantially enantiomerically pure esomeprazole in neutral form or as a pharmaceutically acceptable salt or as its solvates including hydrates. Thus, for example, a compound containing a mixture of 1-(S)-camphorsulfonyl-5-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl)methyl-(S)-sulfinyl]-1H-benzimidazole and 1-(S)-camphorsulfonyl-6-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridyl)methyl-(S)-sulfinyl]-1H-benzimidazole is hydrolyzed with barium hydroxide, isolated the resulting esomeprazole barium salt followed by neutralization with an acid to yield substantially enantiomerically pure esomeprazole in neutral form and then converted into its pharmaceutically acceptable salts.