[Simultaneous determination of 5 sedative hypnotics in human plasma by reversed phase high-performance liquid chromatography].
OBJECTIVE
To determine diazepam, nitrazepam, oxazepam, estazolam, and alprazolam 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 microL mobile phase. The blood drug levels were analyzed by high performance liquid chromatograph with 20 microL sample injection on a chromatographic column C18 (4.6 mm x 250 mm) at 30 degree. 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 microg/L (r> or =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).


CONCLUSIONS
RP-HPLC method is convenient, accurate and sensitive for simultaneous determination of the concentration of diazepam, nitrazepam, oxazepam, estazolam, and alprazolam in human plasma.
Liang
Xianghui
X
Department of Clinical Laboratory, Xiangya Hospital, Central South University, Changsha 410008, China. liangxhhn@yahoo.com.cn
Dai
Zhiyong
Z
Liu
Wen'en
W
D000525:Alprazolam / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003975:Diazepam / Q000097:blood; D004949:Estazolam / Q000097:blood; D006801:Humans; D006993:Hypnotics and Sedatives / Q000097:blood*; D009567:Nitrazepam / Q000097:blood; D010076:Oxazepam / Q000097:blood
D006993:Hypnotics and Sedatives; D004949:Estazolam; D010076:Oxazepam; D009567:Nitrazepam; D003975:Diazepam; D000525:Alprazolam