title: Simultaneous determination of carisoprodol and acetaminophen in an attempted suicide by liquid chromatography-mass spectrometry with positive electrospray ionization.
abstract: An adult female ingested a considerable quantity of carisoprodol/acetaminophen tablets, which are not commercially available in Japan, in an attempt to commit suicide. Generally, because of lack of the appreciable ultraviolet absorbance or fluorescence, carisoprodol and its major metabolite meprobamate are determined by gas chromatography or gas chromatography-mass spectrometry. Complicated derivatization is, however, necessary to that methodology. Thus, we investigated the derivatization-free, highly sensitive, and simultaneous determination of carisoprodol, meprobamate, and acetaminophen by means of liquid chromatography-mass spectrometry (LC-MS) with positive electrospray ionization. A semi-micro ODS column was used. Ammonium acetate solution (10mM) and acetonitrile were used as mobile phase at a flow rate of 150 microL/min using gradient elution. MS parameters were as follows: capillary voltage, 3.5 kV; cone voltage, +30 V; extractor voltage, 5 kV; and ion source temperature, 100 degrees C. Urine samples pretreated by Oasis HLB cartridge, or plasma samples deproteinized by adding ice-cold acetonitrile were analyzed by LC-MS. The limits of quantitation for each compound were as follows: 0.50 ng/mL for carisoprodol; 10 ng/mL for acetaminophen; and 1.0 ng/mL for meprobamate. In the present case, carisoprodol and acetaminophen were the only drugs detected. Meprobamate was also found as the metabolite of carisoprodol in both urine and plasma. The plasma levels of carisoprodol, acetaminophen, and meprobamate on arrival were 29.5, 245, and 46.7 microg/mL, respectively. These levels were extremely high compared with therapeutic plasma concentrations. Despite the high plasma concentrations of these drugs, which correspond to fatal levels, the patient survived.
authors.affiliation: Criminal Investigation Laboratory, Aichi Prefectural Police Hdqrs., 1-1 Sannomaru 2-chome, Naka-ku, Nagoya 460-8502, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sano
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Minoru
authors.initials: M
authors.lastname: Aoki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Maeno
authors.forename: Masataka
authors.initials: M
authors.lastname: Nagao
mesh_terms: D000082:Acetaminophen / Q000097:blood / Q000506:poisoning* / Q000652:urine; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000097:blood / Q000506:poisoning* / Q000652:urine; D002328:Carisoprodol / Q000378:metabolism / Q000506:poisoning*; D002853:Chromatography, Liquid; D004338:Drug Combinations; D062787:Drug Overdose; D005260:Female; D006801:Humans; D008620:Meprobamate / Q000097:blood / Q000652:urine; D009125:Muscle Relaxants, Central / Q000378:metabolism / Q000506:poisoning*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013406:Suicide, Attempted; D013997:Time Factors
chemical_list: D018712:Analgesics, Non-Narcotic; D004338:Drug Combinations; D009125:Muscle Relaxants, Central; D002328:Carisoprodol; D000082:Acetaminophen; D008620:Meprobamate