Stability Indicating LC-DAD Method for Determination of Nadifloxacin and Characterization of Its Degradation Products by LC–ESI–MS/MS

Abstract

Nadifloxacin, a second generation fluoroquinolone, is a topical antibiotic prescribed for acne vulgaris. For any drug, understanding the stability profile is of vital significance as it correlates with the safety and potency of the drug. In the present study, the degradation behaviour of nadifloxacin was studied under different forced degradation conditions. The drug was subjected to acidic, basic, neutral, thermal, photolytic and reduction degradation conditions to evaluate its intrinsic stability. The forced degradation study showed extensive degradation under acidic and reduction conditions, with the formation of nine degradants. A RP-HPLC gradient method was developed for the separation of nadifloxacin and its degradants on a Kromasil C18 (250 mm × 4.6 mm, 5 µm) HPLC column, using ammonium acetate pH 4.5 and acetonitrile as mobile phase. The developed HPLC method has been validated as per ICH guidelines for specificity, linearity, accuracy, LOD and LOQ, precision and robustness. LC–ESI–MS ⁿ helped in structural elucidation of degradants and a degradation pathway for nadifloxacin has been proposed. The developed HPLC method can thus be employed as stability indicating method for routine quality control analysis of the drug in bulk samples.