title: Monitoring of olanzapine in serum by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.
abstract: A selective assay of olanzapine with liquid chromatography atmospheric pressure chemical ionization (LC-APCI-MS, positive ions) is described. The drug and internal standard (ethyl derivative of olanzapine) were isolated from serum using a solid-phase extraction procedure (C18 cartridges). The separation was performed on ODS column in acetonitrile-50 mM ammonium formate buffer, pH 3.0 (25:75). After analysis of mass spectra taken in full scan mode, a selected-ion monitoring detection (SIM) was applied with the following ions: m/z 313 and 256 for olanzapine and m/z 327 and 270 for the internal standard for quantitation. The limit of quantitation was 1 microg/l, the absolute recovery was above 80% at concentration level of 10 to 100 microg/l. The method tested linear in the range from 1 to 1000 microg/l and was applied for therapeutic monitoring of olanzapine in the serum of patients receiving (Zyprexa) and in one case of olanzapine overdose. Olanzapine in frozen serum samples and in frozen extracts was stable over at least four weeks. The examinations of urine extracts from patients receiving olanzapine revealed peaks of postulated metabolites (glucuronide and N-desmethylolanzapine).
authors.affiliation: Institute of Forensic Medicine, Aachen University of Technology, Klinikum RWTH, Germany.
authors.forename: M J
authors.initials: MJ
authors.lastname: Bogusz
authors.forename: K D
authors.initials: KD
authors.lastname: Krüger
authors.forename: R D
authors.initials: RD
authors.lastname: Maier
authors.forename: R
authors.initials: R
authors.lastname: Erkwoh
authors.forename: F
authors.initials: F
authors.lastname: Tuchtenhagen
mesh_terms: D014150:Antipsychotic Agents / Q000097:blood* / Q000378:metabolism; D001274:Atmospheric Pressure; D001569:Benzodiazepines; D002853:Chromatography, Liquid / Q000379:methods*; D016903:Drug Monitoring; D004355:Drug Stability; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D000077152:Olanzapine; D010890:Pirenzepine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D010890:Pirenzepine; D000077152:Olanzapine