title: Specific and sensitive analysis of nefopam and its main metabolite desmethyl-nefopam in human plasma by liquid chromatography-ion trap tandem mass spectrometry.
abstract: A specific and sensitive liquid chromatography-tandem mass spectrometric (LC-MS-MS) method using an ion trap spectrometer was developed for quantitation of nefopam and desmethyl-nefopam in human plasma. Nefopam, desmethyl-nefopam and the internal standard (ethyl loflazepate) were extracted in a single step with diethyl ether from 1 mL of alkalinized plasma. The mobile phase consisted of acetonitrile with 0.1% formic acid (50:50, v:v). It was delivered at a flow-rate of 0.3 mL/min. The effluent was monitored by MS-MS in positive-ion mode. Ionisation was performed using an electrospray ion source operating at 200 degrees C. Nefopam and desmethyl-nefopam were identified and quantified in full scan MS-MS mode using a homemade MS-MS library. Calibration curves were linear over the concentration range of 0.78-100 ng/mL with determination coefficients >0.996. This method was fast (total run time<6 min), accurate (bias<12.5%), and reproducible (intra- and inter-assay precision<17.5%) with a quantitation limit of 0.78 ng/mL. The high specificity and sensitivity achieved by this method allowed the determination of nefopam and desmethyl-nefopam plasma levels in patients following either intermittent or continuous intravenous administration of nefopam.
authors.affiliation: Laboratoire de Pharmacologie et Toxicologie, Hôpital Maison Blanche, CHU de Reims, 45 rue Cognacq-Jay, 51092 Reims Cedex, France. ghoizey@chu-reims.fr
authors.forename: Guillaume
authors.initials: G
authors.lastname: Hoizey
authors.forename: Anne
authors.initials: A
authors.lastname: Goglin
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Malinovsky
authors.forename: Arnaud
authors.initials: A
authors.lastname: Robinet
authors.forename: Laurent
authors.initials: L
authors.lastname: Binet
authors.forename: Matthieu L
authors.initials: ML
authors.lastname: Kaltenbach
authors.forename: Hervé
authors.initials: H
authors.lastname: Millart
authors.forename: Denis
authors.initials: D
authors.lastname: Lamiable
mesh_terms: D002138:Calibration; D002853:Chromatography, Liquid; D006801:Humans; D007275:Injections, Intravenous; D009340:Nefopam / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry
chemical_list: C477699:desmethyl-nefopam; D009340:Nefopam