Lansoprazole Des sulphur impurity (Crude)

Lansoprazole Des sulphur impurity (Crude) is a benzimidazole-based degradation byproduct arising from the oxidative desulfurization of the parent lansoprazole molecule. It retains the 3,4-dimethoxy-2-fluoroaniline moiety and methoxy-substituted benzimidazole core but lacks the sulfinyl bridge characteristic of the active pharmaceutical ingredient. The compound features a reduced sulfur center, replacing the sulfinyl group with a methylene linkage, and exhibits a planar conformation due to conjugation between aromatic rings. This impurity is specifically employed as an HPLC reference standard for quantifying process-related desulfurization byproducts in lansoprazole API batches.