Gatifloxacin hydroxy acid impurity

Gatifloxacin hydroxy acid impurity is a fluoroquinolone derivative characterized by a substituted quinolone core bearing a hydroxyl group at the 8-position and a carboxylic acid moiety at the 3-position. It features two fluorine atoms at C-6 and C-8, a cyclopropylmethyl group at C-1, and a piperazin-1-yl substituent at N-7. This impurity arises from oxidative degradation of the parent drug's methoxy group, introducing a hydroxyl functionality. Its structural similarity to gatifloxacin enables use as an HPLC reference standard for impurity profiling in active pharmaceutical ingredient (API) quality control.