Liquid chromatographic and spectrophotometric determination of diflucortolone valerate and chlorquinaldol in creams

Abstract

A new reversed phase high pressure liquid chromatography and a spectrophotometric method are proposed for the simultaneous determination of diflucortolone valerate (DIF) and chlorquinaldol (CHL) in creams. An isocratic system consisted of an ACE® C18 analytical column and a mobile phase composed of methanol/phosphate buffer (pH 5.5, 0.1 M) (95:5, v/v) at a flow rate 1.0 mL/min was used for the optimal chromatographic separation using UV detection at 220 nm. Ephedrine hydrochloride was used as internal standard. Principal component regression (PCR) was used as the chemometric technique in spectrophotometry. In this technique, the concentration data matrix was prepared by using the synthetic mixtures containing these drugs in methanol/water (3:1). The absorbance data matrix corresponding to the concentration data matrix was obtained by measuring the absorbances at 60 wavelengths in the range of 230-348 nm with appropriate interval Δλ of 2 nm for DIF and CHL in the zero-order spectra for the binary combinations. The linear ranges were found 2.40-300 μg/mL for DIF, 0.72-240 μg/mL for CHL for LC method, and 0.88-3.0 μg/mL for DIF and 1.0-11.2 μg/mL for CHL for PCR method. The accuracy, precision and the linear ranges of the methods have been evaluated and they have been validated by analyzing synthetic mixtures containing the title drugs. These two methods were successfully applied to two pharmaceutical cream preparations and the results were compared with each other.