High Performance Liquid Chromatographic Assay for Basic Amine Drugs in Plasma and Urine Using a Silica Gel Column and an Aqueous Mobile Phase. II. Chlorpheniramine

Abstract A high performance liquid chromatographic [HPLC] method that involves the use of a silica gel column and an aqueous mobile phase for quantitation of chlorpheniramine in plasma and urine is presented. Alkalinized samples are cleaned by extraction with pentane [containing 1% CH3CN], and the extraction is followed by evaporating the solvent and reconstituting the residue in a small amount of mobile phase. An aliquot of this solution is analyzed by an HPLC system with an Ultrasphere Si Column, an aqueous mobile phase at pH 7 containing 60% CH3CN and 7.5 mM [NH4]2HPO4, and UV detection at 200 nm. Although the average recovery of extraction is 58% ± SD 10%, the detection limit for the method is 0.7 ng/ml in plasma and 100 ng/ml in urine [s/n = 3] for 0.5 ml samples. The coefficients of variation [CV] on the results of samples run to measure interday and intraday precision and the bias on control samples were all 10% or less. We have used the method in a bioavailability study of a controlled release for...