QUANTITATIVE-ANALYSIS OF SORBIC ACID IN PHARMACEUTICAL CREAM FORMULATIONS BY LIQUID-CHROMATOGRAPHY ON POLY(STYRENE-DIVINYLBENZENE)

A method is described for quantitative analysis of sorbic acid in fat soluble cream formulations. A poly(styrene-divinylbenzene) column (PLR P-S 8 mu m 100 Angstrom, 250x4.6 mm I.D.), maintained at 60 degrees C was used. The mobile phase was acetonitrile-0.2 M phosphate buffer (pH 7.0)-water (1:5:94, v/v/v). The flow-rate was 1.0 ml min(-1) and UV d etection was performed at 254 nm. Sample preparation was carried out b y treatment of the cream formulations with a mixture of hexane and mob ile phase. The method showed good repeatability, linearity and recover y. It was observed that in most of the creams examined the stability o f sorbic acid was poor.