Determination of GHB and GHB-β-O-glucuronide in hair of three narcoleptic patients—Comparison between single and chronic GHB exposure

Abstract Gamma-hydroxybutyric acid (GHB) can be used as a knock-out drug in drug facilitated crime (DFC). Due to its rapid metabolism and resulting narrow detection window, uncovering GHB use in DFC still constitutes a problem. In this experiment we determined the GHB and GHB-β- O -glucuronide (GHB-Gluc) concentrations in hair samples after single and chronic GHB exposures. Hair samples of three narcoleptic patients therapeutically taking sodium oxybate (GHB-sodium-salt) were collected. Patients 1 (P1) and 2 (P2) took the medication for nine and six years, respectively. P1 took daily the pharmaceutical Xyrem ® in a total dose of 5.78 g GHB at bed time (2.89 g) and four hours (2.89 g) later. P2 took a dose of 3.10 g GHB at bed time and an additional dose of 2.68 g GHB four hours later. Patient 3 (P3) was newly diagnosed with narcolepsy and started his therapy with oral dose of 6 g (divided in three portions of 2 g GHB) within 24 h. The hair samples were extracted both with and without forerunning washing steps. GHB and GHB-Gluc were determined by a published ultra-high performance liquid chromatography–tandem mass spectrometry method using GHB- d 6 and GHB-Gluc-d 4 as internal standards. GHB and GHB-Gluc concentrations in unwashed hair samples of P1 and P2 were determined in a range of 0.56–1.30 ng/mg and