Determination of methylparaben, propylparaben and chlorpromazine in chlorpromazine hydrochloride oral solution by high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic assay method was developed and validated for the simultaneous determination of methylparaben and propylparaben preservatives and chlorpromazine hydrochloride active component in a liquid oral pharmaceutical formulation. The method separated the analytes as well as some degradants and other components, providing good resolution and moderate tailing. The performance of various C18 columns was compared. There were significant differences in selectivity and only a few phases showed acceptable tailing without the addition of triethylamine modifier in the mobile phase.