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.
Ferrara
S D
SD
Centre of Behavioural and Forensic Toxicology, University of Padova, Italy.
Tedeschi
L
L
Frison
G
G
Castagna
F
F
Gallimberti
L
L
Giorgetti
R
R
Gessa
G L
GL
Palatini
P
P
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