QUANTITATIVE HPTLC DETERMINATION OF SALICYCLIC ACID IN TOPICAL ACNE MEDICATIONS

A method was developed for determination of salicylic acid in anti-acn e pharmaceutical preparations involving separation on a preadsorbent h igh performance thin layer chromatography (HPTLC) silica gel plate wit h fluorescent phosphor, detection by fluorescence quenching, and quant ification by densitometric scanning. Salicylic acid was directly detec ted and quantified on the plate at levels as low as 1 mu g, and no int erference was encountered from other ingredients in the medication for mulations. The method was applied to the analysis of a commercial gel preparation with a label value of 2.0% salicylic acid, and an average value of 99.2% of theoretical was obtained (n=16). Accuracy was valida ted by analysis of a 10% benzoyl peroxide anti-acne gel spiked with 2% salicylic acid, and recovery averaged 100.0% (n=10). The coefficients of variation for the analyses were 3.9 and 5.6%, respectively. Advant ages of the new HPTLC method are discussed.