Stability-indicating method for the analysis of amorolfine and its N-oxide degradation product

Abstract

This work aimed to validate a stability-indicating method for determining amorolfine (AMF) in topical formulations by HPLC-DAD. The tailing factor, capacity factor, and theoretical plates were optimized by employing the desirability function. AMF was quantified in a hydrophilic formulation produced in our laboratory and Loceryl® cream and lacquer. Reverse-phase HPLC method with detection at 218 nm showed selectivity (peak purity> 995), robustness (RSD <2.0%), linearity (35–325 μg.mL-1), accuracy (≈100.0%), precision (RSD <2.0%) and limit of quantitation of 750 ng.mL-1. Forced degradation of AMF in an oxidative medium containing hydrogen peroxide resulted in a degradation product that was purified and identified as an N-oxide. The degradation kinetics was pH-dependent.

Keywords

• Amorolfine, N-oxide, HPLC, mass spectrometry, Loceryl