DETERMINATION OF ALPRAZOLAM AND ALPHA-HYDROXYALPRAZOLAM IN PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A high-performance liquid chromatography (HPLC) assay was developed fo r the determination of alprazolam and its active metabolite, alpha-hyd roxyalprazolam, in human plasma. Alprazolam, alpha-hydroxyalprazolam a nd estazolam as an internal standard were detected by ultraviolet abso rbance at 230 nm. Alprazolam and alpha-hydroxyalprazolam in plasma wer e extracted by a rapid and simple procedure based on cyanopropyl bonde d-phase extraction. A Ca reversed-phase HPLC separation technique was developed. Determination of alprazolam was possible in the concentrati on range at 1.0-50 ng/ml and alpha-hydroxyalprazolam in range at 0.5-1 0 ng/ml. The mean recoveries of alprazolam and alpha-hydroxyalprazolam added to plasma were 98.05+/-5.75% and 96.25+/-5.70%, respectively, w ith the relative standard deviation of less than 7.8 and 10.6%. The me thod is applicable to drug monitoring of alprazolam and alpha-hydroxya lprazolam level in plasma of healthy volunteers and patients treated w ith alprazolam.