Comparison of two gas-liquid chromatographic methods for the determination of nitrazepam in plasma.
Nitrazepam in plasma was determined by gas-liquid chromatography with a nickel-63 electron-capture detector, unchanged by a direct method and also by a hydrolysis method. The extraction in the direct method was carried out with benzenedichloromethane (90:10) and in the hydrolysis method with diethyl ether. The hydrolysis was performed with 6 N sulphuric acid. The hydrolysis product was extracted with toluene-n-heptane-ethyl acetate (80:20:5) directly from acid. Thus the commonly used change in pH was omitted. Nitrazepam concentrations in plasma were determined in 10 healthy volunteers after two oral doses (5 and 10 mg); 0.5 ml of plasma was used for each determination and clonazepam, methylbromazepam and methylnitrazepam were used as internal standards. The recoveries of the methods are almost quantitative (greater than 96%). The two methods are clinically comparable. The high sensitivity and specificity make these methods useful in clinical determinations of nitrazepam in plasma. Advantages and disadvantages of both methods are discussed.
D000328:Adult; D055598:Chemical Phenomena; D002621:Chemistry; D002849:Chromatography, Gas / Q000379:methods; D004583:Electrons; D005260:Female; D006801:Humans; D006868:Hydrolysis; D008297:Male; D008832:Microchemistry; D009567:Nitrazepam / Q000097:blood*
D009567:Nitrazepam