Capillary GC Determination of Fentanyl and Midazolam in Human Plasma

✍ Scribed by Liu Yuansheng; Wu Yutian; Zhou Jing; Zhai Zhenxing; Qi Zhanxi; Gao Shen; Kong Qinghong; Wang Xinhua

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 83 KB
• Volume: 53
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1996.0017

✦ Synopsis

A capillary GC method is described for simultaneously measuring fentanyl and midazolam in human plasma. Plasma was extracted at basic pH with cyclohexane-isopentanol (197:3) with Ro21-2212 added as internal standard and fentanyl derivative as carrier. The drug was back-extracted in H 2 SO 4 , and then the extract was made basic and reextracted with hexane. The organic phase was evaporated at 40°C under N 2 and the residue was dissolved in ethanol. A portion was analyzed on a wide-bore capillary column (10 m × 0.53 mm) of HP-1 (2.65 m), operated at 255°C with N 2 as carrier gas and N-P detector. The calibration graph for fentanyl and midazolam was linear within the respective ranges of 0.5-100 and 5-1000 ng/ml with a correlation coefficient of 0.9998. The recovery of fentanyl and midazolam was 99.5 ± 4.5 and 99.9 ± 3.2%. The coefficient of variation within a run and between runs was less than 7%. The detection limit for fentanyl was 0.2 ng/ml plasma, and for midazolam was 0.5 ng/ml plasma. The method was applied to therapeutic drug monitoring and pharmacokinetic studies.1996 Academic Press, Inc.