Electron Capture Gas Chromatography of Nitrazepam in Human Plasma as Methyl Derivative

Abstract
A method for quantitative determination of nitrazepam in human plasma in the range 5 - 100 ng/ml is presented. Nitrazepam is extracted with benzene from plasma samples of 0.5 ml, methylated with methyl iodide and determined gas chromatographically with an electron capture detector of 63Ni-type. Acid dissociation constants of nitrazepam are determined and the partition properties studied with benzene, methylene chloride and diethyl ether as organic phases. The selectivity of the method with respect to the metabolites has been thoroughly studied.