Haver V M, Porter W H, Dorie L D, Lea J R
Ther Drug Monit. 1986;8(3):352-7. doi: 10.1097/00007691-198609000-00020.
A convenient and sensitive high performance liquid chromatographic method was developed for determination of clonazepam in serum using a C-18 reverse-phase column, and mobile phase consisting of a 50:35:15 mixture by volume of pH 6.0 phosphate buffer:methanol:acetonitrile. Quantitation was performed at 313 nm with flunitrazepam as the internal standard. Using 1 ml of serum for extraction, the assay is linear for clonazepam concentrations between 10 and 250 ng/ml. The relative recovery averaged 100.3%, and the coefficient of variation for between-day and within-day assays was less than 7%. A simple modification permits analysis of 200 microliter of serum, with little loss of precision and with a detection limit of 20 ng/ml. Only three drugs tested (nitrazepam, methaqualone, and norchlordiazepoxide) interfered with the assay, and none are likely to be used therapeutically with clonazepam. Importantly, carbamazepine and carbamazepine-10,11-epoxide do not interfere under the conditions of the assay. The method is equally suitable for the determination of nitrazepam. By adjusting the mobile phase so that volume ratios of phosphate buffer, methanol, and acetonitrile are 45:35:20, and using nitrazepam as the internal standard, seven other benzodiazepines (demoxepam, oxazepam, chlordiazepoxide, norchlordiazepoxide, temazepam, diazepam, and nordiazepam) can be resolved at 254 nm.
建立了一种简便、灵敏的高效液相色谱法，用于测定血清中的氯硝西泮。采用C-18反相柱，流动相由体积比为50:35:15的pH 6.0磷酸盐缓冲液:甲醇:乙腈组成。以氟硝西泮为内标，在313 nm处进行定量分析。采用1 ml血清进行萃取，该方法对氯硝西泮浓度在10至250 ng/ml之间呈线性关系。相对回收率平均为100.3%，日间和日内测定的变异系数均小于7%。一个简单的改进允许分析200微升血清，精度损失很小，检测限为20 ng/ml。仅三种测试药物（硝西泮、甲喹酮和去甲氯氮卓）干扰该测定，且它们都不太可能与氯硝西泮一起用于治疗。重要的是，在该测定条件下，卡马西平和卡马西平-10,11-环氧化物不产生干扰。该方法同样适用于硝西泮的测定。通过调整流动相，使磷酸盐缓冲液、甲醇和乙腈的体积比为45:35:20，并以硝西泮为内标，在254 nm处可分离出其他七种苯二氮䓬类药物（地美西泮、奥沙西泮、氯氮卓、去甲氯氮卓、替马西泮、地西泮和去甲地西泮）。
