Comparative study of two different chromatographic approaches for quantitation of hydrocortisone acetate and pramoxine hydrochloride in presence of their impurities

In the present study, we compare the performance of two reversed-phase liquid chromatographicapproaches using different eluents either conventional hydro-organic eluentor micellar one for simultaneous estimation of hydrocortisone acetate and pramoxinehydrochloride in presence of their degradants and process-related impurities; hydrocortisoneand 4-butoxyphenol, respectively. For conventional reversed-phase liquid chromatography(RPLC), separation of the studied compounds was completed on an Inertsil ODS 3-C18 column (150 mm _ 4.6 mm, 5 mm particle size) with a mobile phase consists of 50 mMphosphate buffer (pH 5.0): acetonitrile (50: 50, v/v). For micellar liquid chromatography(MLC), an Eclipse XDB-C8 column (150mm _ 4.6 mm, 5 mm particle size) was chosen for theseparation with a green mobile phase consists of 0.15 M sodium dodecyl sulfate, 0.3%triethylamine and 10% n-butanol in 20 mM orthophosphoric acid (pH 5.0). Both methodswere extended to analyze hydrocortisone acetate and pramoxine hydrochloride in their coformulatedcream. RPLC was superior to MLC with regard to sensitivity for the estimationof impurities. While, MLC represents an eco-friendly, less hazardous and biodegradableapproach. Furthermore, the direct injection of the cream to the system without the need tolaborious samples pretreatment, excessive amount of analysis time and/or use of largeamount of toxic organic solvents is one of the outstanding advantages of MLC.