title: Determination of midazolam and 1'-hydroxymidazolam by liquid chromatography-mass spectrometry in plasma of patients undergoing methadone maintenance treatment.
abstract: A rapid, sensitive and selective LC-MS method was developed for the simultaneous determination of midazolam (MDZ) and 1'-hydroxymidazolam (1'-OHMDZ) in plasma taken from 54 patients undergoing methadone maintenance therapy, most of whom were multidrug users. Samples spiked with prazepam, the internal standard, and were extracted into diethyl ether. Compounds were separated on a Phenomenex Luna C(18) column and a mobile phase of acetonitrile-ammonium acetate buffer (10 mM, pH 4.7) (52:48, v/v) at a flow-rate of 1 ml/min. The limit of detection was 0.65 and 0.68 (ng/ml) for MDZ and 1'-OHMDZ, respectively. Within-day relative standard deviations were less than 8%.
authors.affiliation: Molecular Pharmacology and Pharmacogenetics, Division of Clinical Sciences, University of Sheffield, UK. m.shiran@Sheffield.ac.uk
authors.forename: M R
authors.initials: MR
authors.lastname: Shiran
authors.forename: A
authors.initials: A
authors.lastname: Gregory
authors.forename: A
authors.initials: A
authors.lastname: Rostami-Hodjegan
authors.forename: G T
authors.initials: GT
authors.lastname: Tucker
authors.forename: M S
authors.initials: MS
authors.lastname: Lennard
mesh_terms: D000759:Adjuvants, Anesthesia / Q000097:blood*; D014151:Anti-Anxiety Agents / Q000097:blood*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D008691:Methadone / Q000627:therapeutic use*; D008874:Midazolam / Q000031:analogs & derivatives* / Q000097:blood*; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000759:Adjuvants, Anesthesia; D014151:Anti-Anxiety Agents; C040081:1-hydroxymethylmidazolam; D008874:Midazolam; D008691:Methadone