Eco-friendly, stability-indicating micellar HPLC-UV method for simultaneous determination of clindamycin phosphate and adapalene in gel formulations

A rapid, accurate, sensitive, and eco-friendly micellar liquid chromatography method has been successfully developed and validated for the simultaneous determination of clindamycin and adapalene in their bulk forms and combined dosage gel formulations. The separation was performed on a BDS HYPERSIL C18 column (150 × 4.6 mm, 5 μm), employing a micellar mobile phase made up of 0.07 M sodium dodecyl sulfate, 0.3% triethylamine, 0.02 M orthophosphoric acid (pH adjusted to 3.0), and 14% isopropanol (v/v). Detection was carried out using UV at 210 nm. The method exhibited linearity in the ranges of 100-500 µg/mL for clindamycin phosphate and 10-50 µg/mL for adapalene, with detection limits of 13.4 µg/mL and 1.4 µg/mL, respectively. The developed method was effectively applied to the analysis of a laboratory-prepared co-formulated gel, yielding high recovery rates. The greenness of the method was further confirmed through assessment with the Green Analytical Procedure Index (GAPI). The method was also validated as a stability-indicating assay for clindamycin phosphate and adapalene under various stress conditions, demonstrating its robustness and applicability for routine quality control.