title: Determination of midazolam and its metabolite as a probe for cytochrome P450 3A4 phenotype by liquid chromatography-mass spectrometry.
abstract: This study demonstrated the analysis of midazolam and its metabolites by liquid chromatography-mass spectrometry (LC-MS) with a sonic spray ionization (SSI) interface. The analytical column was a YMC-Pak Pro C18 (50 mm x 2.0 mm i.d.) using 10 mM ammonium acetate (pH 4.8)-methanol (1:1) at a flow rate of 0.2 ml min(-1). The drift voltage was 100 V. The sampling aperture was heated at 110 degrees C and the shield temperature was 230 degrees C. The lower limits for the detection of midazolam and 1'-hydroxymidazolam were 26.3 and 112.76 pg injected, respectively. The calibration curves for midazolam and 1'-hydroxymidazolam were linear in the range of 0.1-5 microg ml(-1). Within-day relative standard deviations was less than 7%. The method was applied to the determination of midazolam in monkey plasma, and the analysis of midazolam and its metabolites in an in vitro study with recombinant cytochrome P450 (CYP) 3A4. This method is sufficiently sensitive and useful to elucidate the kinetics of midazolam metabolite formation. We also investigated the effect of propofol on the metabolism of midazolam using recombinant CYP3A4. Propofol competitively inhibited the metabolism of midazolam to 1'-hydroxymidazolam by CYP3A4.
authors.affiliation: Department of Physical Chemistry, Kyoritsu College of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan. kanazawa-hd@kyoritsu-ph.ac.jp
authors.forename: Hideko
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Okada
authors.forename: Eri
authors.initials: E
authors.lastname: Igarashi
authors.forename: Megumu
authors.initials: M
authors.lastname: Higaki
authors.forename: Takako
authors.initials: T
authors.lastname: Miyabe
authors.forename: Tadashi
authors.initials: T
authors.lastname: Sano
authors.forename: Ryouhei
authors.initials: R
authors.lastname: Nishimura
mesh_terms: D000818:Animals; D001711:Biotransformation; D002138:Calibration; D002853:Chromatography, Liquid; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D004347:Drug Interactions; D006801:Humans; D006900:Hydroxylation; D006993:Hypnotics and Sedatives / Q000032:analysis* / Q000493:pharmacokinetics* / Q000494:pharmacology; D066298:In Vitro Techniques; D008251:Macaca; D013058:Mass Spectrometry; D008874:Midazolam / Q000032:analysis* / Q000493:pharmacokinetics*; D010084:Oxidation-Reduction; D010641:Phenotype; D015742:Propofol / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D006993:Hypnotics and Sedatives; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D008874:Midazolam; D015742:Propofol