DETERMINATION OF ANTIBACTERIAL QUATERNARY AMMONIUM-COMPOUNDS IN LOZENGES BY CAPILLARY ELECTROPHORESIS

A method for the specific determination of three quaternary ammonium c ompounds, benzalkonium chloride, cetylpyridinium chloride and dequalin ium chloride, used as antibacterial agents in candy-based lozenges, is described based on capillary zone electrophoresis. It is shown that, following optimisation of buffer composition with respect to organic m odifier concentration, pH and buffer concentration together with the i nclusion of sodium dodecylsulphate as an ion-pairing agent in the case of dequalinium chloride, these analytes migrate in less than 5 min. T he resultant electrophoretic peaks are sharp and readily quantified. T he individual alkyl components of benzalkonium chloride can be resolve d as can related impurities in dequalinium chloride lozenges. The quan titative characteristics of the assay method, based on peak areas norm alised with respect to migration times, are reported and the method is compared with a previously published method based on liquid chromatog raphy. (C) 1998 Published by Elsevier Science B.V.