Development and Validation of a LC–MS/MS Method for the Profiling of Impurities Formed during Stress Study of Antifungal Agent—Efinaconazole

Liquid chromatography interfaced with mass spectroscopy (LC-MS) is a sensitive and effective analytical method that combines high-resolution separation as well as specific mass detection of impurities in formulated products and as well as in active pharmaceutical ingredient (API). In this study, LC-MS/MS was used to determine impurities formed during the stability period of Efinaconazole (EFZ, a triazole antifungal agent). The method was validated for its assay parameters such as specificity, linearity, accuracy, precision and also for solution stability. The calibration curve was found to be linear for the concentration range from 0.5 μg/mL to 30 μg/mL. A thorough investigation was performed by exposing Efinaconazole (1 mg/mL) to various stress conditions such as hydrolysis (acid and alkaline), oxidation, photolysis and temperature at various time intervals to achieve 10% degradation. The impurities formed during forced degradation were separated using high-performance liquid chromatography later it was identified using LC-MS/MS technique. The obtained results showed that EFZ is prone to oxidation when exposed to a 3% aqueous medium of hydrogen peroxide solution and quite stable in all the remaining stress conditions for a longer period.