Patent ID: 8680284

Claim:
A preparation process of esomeprazole having a content of 5-methoxy-2-[(S)-[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfonyl]-1H-benzimidazole equal to or lower than 0.5% w/w comprising the steps of: a) either a 1 ) combining a solution of esomeprazole in a (C 3 -C 8 )-ketone or a mixture thereof, with a sodium alkoxide, and a (C 1 -C 5 )-alcohol; or a 2 ) dissolving esomeprazole sodium with a (C 3 -C 8 )-ketone or a mixture thereof, and a (C 1 -C 5 )-alcohol to form a solution; and b) recovering the esomeprazole sodium formed, from the reaction media of step a) which comprises a (C 3 -C 8 )-ketone or a mixture thereof and a (C 1 -C 5 )-alcohol, by filtration.