[Quantitative analysis of chlorpheniramine maleate in cough and cold drugs by ion-pair high-performance liquid chromatography for the simultaneous determination of chlorpheniramine and maleate].

: A simple, rapid and convenient chromatographic method, which permits the simultaneous determination of chlorpheniramine (CP) and maleate (MA), recently developed by the authors was applied to the analysis of chlorpheniramine maleate (CPM) in cough and cold drugs. In this method, a Capcell Pak C8 column and an isocratic mobile phase containing 15% methanol, 50 mM KH2PO4 and 5mM tetra-n-butylammonium phosphate as an ion-pair reagent were used. By using the mobile phase adjusted to pH 3.0 with orthophosphoric acid, fumaric acid, MA, CP, acetaminophen (paracetamol), caffeine, and m- and p-hydroxybenzoic acid as candidates for an internal standard were eluted separately within 17 min. Detection was carried out with UV detector at 215 nm. Under the same conditions, five other antihistamines analogous to CPM were also separated. The calibration graphs for CP and MA showed good linearity in the range of 0.5-10 nmol (0.195-3.9 micrograms) per 20 microliters injection, respectively. The proposed method was successfully applied to the simultaneous determination of CP and MA, i.e., CPM analysis, in commercial cough and cold drugs which pharmaceutical forms were tablet, granule and syrups.