Quantitative analysis of quaternary ammonium antiseptics using thin-layer densitometry

Abstract

A thin-layer chromatography method for quantitative analysis of quaternary ammonium antiseptics is described. Silanized silica gel was used as the stationary phase. The moille phase consisted of mcthal101-15rc (rn/v) sodium acetate solution-acetone (65:35:20). The method is able to separate the chain homologues of benzalkonium chloride, cetylpyridinium chloride and cetrimide. Detection was performed using a colour reaction with potassium triiodide solution. The different homologues were quantified using UV densitometry at 400 nm. A number of commercial samples was analysed using this method. From the results it appears that it is worthwhile to have a limit test for the composition of quaternary ammonium antiseptics in pharmacopoeial monograph, the more so as the antibacterial activity depends on it.