Mirabegron EP impurity G

Mirabegron EP impurity G is a structurally related degradation byproduct arising from oxidative cleavage of the benzimidazole core in Mirabegron, resulting in a truncated aromatic ring system with a terminal carboxylic acid functionality. This impurity retains the piperidine-based side chain but exhibits a loss of the methoxy substituent at the 5-position of the benzene ring, replaced by a hydroxyl group conjugated to a dicarboxylic acid moiety. The compound serves as a critical HPLC reference standard for quantifying degradation pathways in stability-indicating assays of Mirabegron formulations.