Determination of amine ingredients in cough-cold liquids by reversed-phase ion-pair high-performance liquid chromatography.

The chromatographic behavior of phenylephrine, codeine, pseudoephedrine, phenylpropanolamine, methoxyphenamine, pheniramine, pyrilamine, dextromethorphan, and chlorpheniramine was examined by reversed-phase, ion-pair high-performance liquid chromatography. An isocratic chromatographic system was devised for the analysis of cough-cold liquids containing these amine drugs by optimization of the mobile phase ionic strength, buffer pH, pairing ion concentration, and secondary ion concentration. Quantitative recovery and excellent precision were demonstrated for the simultaneous determination of phenylpropranolamine, dextromethorphan, and chlorpheniramine in a typical formulation. The method was successfully applied to various commercial cough-cold liquids for the analysis of a wide range of amine drugs.