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

An isocratic HPLC system for quantifying benzoylecgonine (BE) and cocaine (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 buffer of pH 7, and sensed by UV spectrophotometry at 235 and 275 nm, simultaneously. The detection limit thus achieved was 0.5 mu g drug per millilitre of VH. By using tetracaine as internal standard, BE and COC can be determined with a coefficient of variation of 6 and 7%, respectively.