SIMULTANEOUS DETERMINATION OF COCAINE AND BENZOYLECGONINE IN VITREOUS-HUMOR BY HPLC

An isocratic HPLC system for quantifying benzoylecgonine (BE) and coca ine (COC) in vitreous humour (VH) was developed. Following solid-phase extraction, the two drugs are chromatographed on a column filled with octadecyl silica packing, eluted with 75% methanol in phosphate buffe r of pH 7, and sensed by UV spectrophotometry at 235 and 275 nm, simul taneously. The detection limit thus achieved was 0.5 mu g drug per mil lilitre of VH. By using tetracaine as internal standard, BE and COC ca n be determined with a coefficient of variation of 6 and 7%, respectiv ely.