Green RP-HPLC method for the simultaneous determination of octenidine and phenoxyethanol in antiseptic formulations:...

A green and efficiency-oriented Reversed Phase High Performance Liquid Chromatography (RP-HPLC) method was developed for the simultaneous determination of octenidine dihydrochloride and phenoxyethanol in antiseptic formulations. Unlike previously published studies, the present work offers a fully detailed, optimized, and rigorously validated isocratic method providing simultaneous quantification with a short run time of approximately 8 minutes. Excellent resolution was achieved using an Agilent Zorbax cyanopropyl column (250 × 4.6 mm, 5.0 µm) with a mobile phase of acetonitrile and water (each containing 0.1% trifluoroacetic acid) at 60 : 40 (v/v), a flow rate of 1 mL min^-1, and detection at 270 nm. The method exhibited linear ranges of 0.5-3.0 µg mL^-1 for octenidine dihydrochloride and 3.0-50.0 µg mL^-1 for phenoxyethanol, and was validated in accordance with the International Council for Harmonization (ICH) guidelines. Greenness assessment confirmed a low environmental impact, while Lean Six Sigma analysis demonstrated excellent efficiency and robustness. The method was successfully applied to pure standards and commercial antiseptic formulations, supporting its suitability for routine quality control.