Therapeutic gamma-hydroxybutyric acid monitoring in plasma and urine by gas chromatography-mass spectrometry.
A gas chromatographic-mass spectrometric (GC-MS) method for the determination of therapeutic levels of gamma-hydroxybutyric acid (GHB) in plasma and urine samples is described. GHB is converted to its lactonic form gamma-butyrolactone (GBL) which is extracted from biological fluids after the addition of the internal standard delta-valerolactone. Final GC-MS analysis is obtained under electron impact selected ion monitoring (SIM) conditions. Mean relative recoveries of GHB from plasma and urine are 75.5% (RSD% = 2.2) and 76.4% (RSD% = 2.4), respectively. The assay is linear over a plasma GHB range of 2-200 micrograms ml-1 (r = 0.999) and a urine GHB range of 2-150 micrograms ml-1 (r = 0.998). Intra- and inter-assay relative standard deviations (n = 5) determined at 10 and 100 micrograms ml-1 are below 5%. The method is simple, specific and accurate, and may be applied for analytical purposes related to pharmacokinetic studies and therapeutic drug monitoring.
Centre of Behavioural and Forensic Toxicology, University of Padova, Italy.
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Ferrara
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Tedeschi
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Frison
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Castagna
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Gallimberti
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Giorgetti
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Gessa
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Palatini
D015107:4-Butyrolactone / Q000097:blood / Q000652:urine; D000437:Alcoholism / Q000188:drug therapy; D016903:Drug Monitoring; D000431:Ethanol / Q000009:adverse effects; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D012978:Sodium Oxybate / Q000097:blood* / Q000627:therapeutic use / Q000652:urine*; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy
D000431:Ethanol; D012978:Sodium Oxybate; D015107:4-Butyrolactone