STABILITY INDICATING METHOD DEVELOPMENT FOR THE ESTIMATION OF DIFLUPREDNATE AND MOXIFLOXACIN IN EYE DROP FORMULATION BY HPLC

Abstract

A simple, rapid, precise, and stability-indicating reverse-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous estimation of Difluprednate (DFP) and Moxifloxacin (MXF) in ophthalmic formulations. Chromatographic separation was achieved on a suitable C18 column using an optimized mobile phase under isocratic conditions, with detection at an appropriate UV wavelength. The developed method showed good linearity over the concentration ranges of 1–5 µg/ml for DFP and 5–25 µg/ml for MXF, with correlation coefficients (r²) of 0.999 for both drugs. System suitability parameters were within acceptable limits, indicating satisfactory chromatographic performance. Accuracy studies demonstrated mean recoveries ranging from 97.94–99.04% for DFP and 98.20–98.41% for MXF. Precision studies showed %RSD values below 2%, confirming the repeatability and robustness of the method. The limits of detection and quantification were found to be 0.15 and 0.45 µg/ml for DFP and 0.10 and 0.35 µg/ml for MXF, respectively. The method was successfully applied to the assay of a marketed ophthalmic formulation. Forced degradation studies under acidic, alkaline, oxidative, and photolytic conditions confirmed the stability-indicating nature of the method, as degradation products were well separated from the analyte peaks. The validated method is suitable for routine quality control and stability studies of Difluprednate and Moxifloxacin in ophthalmic dosage forms.

Keywords
Difluprednate, Moxifloxacin, RP-HPLC, Stability-indicating method, Method validation, Ophthalmic formulation.