EXTRACTION OF BASIC DRUGS FROM WHOLE-BLOOD AND DETERMINATION BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A new method for the extraction of basic drugs from whole blood based on the use of a buffered protein precipitating reagent at pH 9, to form NiWO4 in biological fluids and a ternary organic extracting phase of density below 1 is proposed. The extract is analysed by high performance liquid chromatography using a Hypersil C-8 column and detection at 230 nm; the mobile phases used consist of binary mixtures of acetonitrile and aqueous solutions containing 20 mmol/l of n-propylamine at pH 5 and n-hexylamine at pH 4, as blockers of the free silanol groups. The proposed method was applied to the determination of 16 basic drugs including narcotics, analgesics, cocaine-related compounds and adulterants, as well as 8 benzodiazepines, in whole blood.