Notes: Omeprazole sulfide-d3 is intended for use as an internal standard for the quantification of omeprazole sulfide (Item No. 18885) by GC- or LC-MS. Omeprazole sulfide is an active metabolite of the gastric H+/K+ ATPase inhibitor omeprazole (Item No. 14880).{14237,30672} Omeprazole sulfide has been used as a precursor in the synthesis of the H+/K+ ATPase inhibitor esomeprazole (Item No. 17303).{65997} It is also a potential impurity in commercial preparations of omeprazole.{65998}