The Preparation of Lipid-Free Extracts of Drugs from Blood for Gas Chromatographic Analysis

Abstract

A method is presented to separate co-extracted biological materials, in particular lipids, from drugs in chloroform extracts of blood. The chloroform is evaporated and the residue is dissolved in a small volume of petroleum ether and partitioned with eight times this volume of 5% aqueous hydrochloric acid. The acidic, basic, and neutral drugs are extracted into the aqueous phase, leaving unwanted materials in the petroleum ether. The recoveries of drugs representative of a variety of types are presented. Reduction of the levels of lipids by factors on the order of 1000-fold is reported.