Evaluation of Heptane/1-Butanol/Water Systems for Separation of Drug Metabolites by Countercurrent Chromatography

Abstract

A small-volume CCC coil (1.07 mm i. d. × 13.5 m, V_c 14.7 ml) has been used to evaluate heptane/ 1-butanol/aqueous buffer systems for potential use in separating drug metabolites. Repeated sample injections can be made and a partition coefficient as high as 40 can be determined in about 4 hrs. Conjugates of p-nitrophenol with glucuronic acid, sulfuric acid and glucose were separated, and the partition coefficients of several N-alkyl anilines, benzylamines and phenylethylamines were measured to emulate chromatographic behavior expected for compounds generated in xenobiotic metabolism. Amines chromatographed well in reverse phase systems above the amine pK_a value. But peaks were distorted when the mobile phase pH was slightly below the amine pK_a for benzyl and phenylethyl amines and about two units below for anilines. The effect of alcoholic hydroxy! substitution and dealkylation is discussed for anilines and derivatives of the drug chioroquine.