Simultaneous determination of 5 sedative hypnotics in human plasma by reversed phase high-performance liquid chromatography / 中南大学学报(医学版)

ABSTRACT

Objective To determine diazepam, nitrazepam, oxazepam, estazolam, and al-prazolam simultaneously in human plasma by reversed phase high-performance liquid chromatography (RP-HPLC). Methods Ten microliter carbamazepine (50 mg/L)as the internal standard was added into 1 mL sample, which contained the 5 mixed sedative hypnotics as standard substance and human plasma as ground substance. They were extracted with acetoacetate from plasma samples, and then were dissolved by 100 μL mobile phase. The blood drug levels were analyzed by high perform-ance liquid chromatograph with 20 μL sample injection on a chromatographic column C 18 (4.6 mm×250 mm)at 30℃. The mobile phase consisted of methanol and water (65:35) , and the flow rate was 1.0 mL/min. The ultraviolet detection wavelength was 230 nm. Results The linearity range of the 5 drugs was 5～1 200 μg/L(r≥0.9966, P<0.05). The recovery rate was 95.5%～105.6%. The extraction recovery rate was more than 75%. The relative standard deviation (RSD) of intra-day and inter-day was less than 10% (n=5). Conclusion RP-HPLC method is convert-ient, accurate and sensitive for simultaneous determination of the concentration of diazepam, nitraze-pam, oxazepam, estazolam, and alprazolam in human plasma.