title: Quantitative analysis of carisoprodol and meprobamate in whole blood using benzylcarbamate and deuterated meprobamate as internal standards.
abstract: Carisoprodol and meprobamate are frequently encountered drugs in impaired driving casework. Deuterated internal standards, although preferred, were not available until recently. Earlier published studies report the use of a variety of non-deuterated internal standards, many of which lack the chemical and physical similarities that are desired for quantitative analysis. Carisoprodol and meprobamate were determined in whole blood using solid-phase extraction and gas chromatography-mass spectrometry with benzylcarbamate and meprobamate-d(7) as internal standards. When benzylcarbamate was used as internal standard, the linear ranges for carisoprodol and meprobamate were 0-20 mg/L and 0-40 mg/L, respectively. The linear range increased to 100 mg/L when meprobamate-d(7) was used. Limits of detection for carisoprodol and meprobamate were 0.2 and 0.4 mg/L, respectively, regardless of the internal standard selection. The limit of quantitation for both drugs using either internal standard was 0.4 mg/L. Accuracies using benzylcarbamate and meprobamate-d(7) were 100-106% and 91-100%, respectively. Corresponding values for precision indicated intra-assay coefficients of variation of 2.6-4.3% for benzylcarbamate and 1.0-2.3% for meprobamate-d(7). No carryover was evident at 100 mg/L, the highest concentration tested, and no interferences were observed. Results indicated that either benzylcarbamate or meprobamate-d(7) is a suitable internal standard for quantitative determination of carisoprodol or meprobamate from whole blood.
authors: Forensic Science Program, College of Criminal Justice, Sam Houston State University, Huntsville, Texas 77341, USA.
authors: Delisa
authors: D
authors: Downey
authors: Kelsie
authors: K
authors: Simons
authors: Kenji
authors: K
authors: Ota
authors: Sarah
authors: S
authors: Kerrigan
mesh_terms: D000818:Animals; D002219:Carbamates / Q000097:blood; D002328:Carisoprodol / Q000097:blood* / Q000737:chemistry; D002417:Cattle; D003903:Deuterium / Q000737:chemistry; D005554:Forensic Medicine / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008620:Meprobamate / Q000097:blood* / Q000737:chemistry; D009125:Muscle Relaxants, Central / Q000097:blood* / Q000737:chemistry; D012015:Reference Standards; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods; D015813:Substance Abuse Detection / Q000379:methods
chemical_list: D002219:Carbamates; D009125:Muscle Relaxants, Central; D002328:Carisoprodol; D008620:Meprobamate; D003903:Deuterium