Determination of Endogenous Levels of GHB in Human Hair. Are there Possibilities for the Identification of GHB Administration through Hair Analysis in Cases of Drug-Facilitated Sexual Assault?

Abstract

We have developed a GC-MS-MS assay for GHB in human hair. Five milligrams of washed hair were hydrolyzed by 1M or 0.01M NaOH before a liquid-liquid extraction with ethyl acetate under acidic conditions. GHB-d(6) was used as the internal standard. TMS derivatives were formed before injection. TBDMS derivatives were used in cases of strong chromatographic interferences or in a confirmatory procedure. Analysis of basal levels of GHB in 61 drug-free donors gave the following results: the mean measured concentration for blond hair was 0.60 ng/mg (n = 12), SD = 0.19 ng/mg, and extreme figures were in the range 0.35-0.95 ng/mg. For brown hair, the mean measured concentration was 0.90 ng/mg (n = 30), SD = 0.42 ng/mg, and extreme figures 0.41-1.86 ng/mg. For black hair, the mean measured concentration was 0.90 ng/mg (n = 19), SD = 0.37 ng/mg, and extreme figures 0.32-1.54 ng/mg, showing no significant differences depending on hair color. Analysis of basal levels of GHB of 12 or more specimens in segmented hair showed a mean concentration of 1.22 ng/mg (0.31-8.4 ng/mg) and a relative standard deviation for each individual ranging from 6.75% to 37.98%. GHB was administered to a healthy 53-year-old white male (light brown hair) at oral dosages of 30, 45, and 60 mg/kg. Beard hair was collected just before administration and 24 h after (and each day for one week for the last dose), and a 7.5-cm scalp hair lock was collected 7 days after the last dose. A rise in GHB concentration was observed in beard hair for the 45 and 60 mg/kg dosages with a maximum at 24 h, whereas no change was observed for the 30 mg/kg dosage. Scalp hair was segmented into 3-mm long segments. The three proximal last segments showed significantly (0.0005 < p < 0.005) different concentrations of GHB (1.22, 1.27, and 1.66 ng/mg, respectively) when compared with the basal physiological level of GHB in this same person (mean = 0.62 ng/mg, SD = 0.15 ng/mg). A case of daily GHB abuse during bodybuilding allowed us to determine a concentration of GHB of 14 ng/mg, in a 2-cm long segment (black hair). A case of rape under the influence of GHB was documented through hair analysis (black hair) and positive analysis of the glass she used. Sampled 7 days after the sexual assault, the three last 3-mm long proximal segments tested for GHB exhibited concentrations of 3.1-5.3 and 4.3 ng/mg, respectively, whereas the mean physiological level determined in this woman was 0.71 ng/mg, SD = 0.17 ng/mg. The authors advise a two-step hair sampling as evidence of GHB consumption: the first sample at the time of exposure to show the contamination by sweat of the proximal segment in case of recent administration with a significant rise of hair level at the root, and the second after at least 3 or 4 weeks to avoid this contamination and determine the levels incorporated in the hair matrix before, during, and after the exposure.

Detection of gamma-hydroxybutyrate in hair: Validation of GC–MS and LC–MS/MS methods and application to a real case

“…The very low concentrations detected in the 2nd and 3rd cm from the scalp well represent the physiological GHB level of the subject, in agreement with the normal level observed in human hair (≤2 ng/mg). The quite higher concentration observed in the first segment was reasonably due to the endogenous GHB incorporation through sweat at the root level, as reported in the literature [11,14].…”

“…We obtained an estimated concentration of 0.28 ng/mg with GC-MS, and 0.27 with LC-MS/MS, in the low end of the range reported in the literature [11][12][13][14][15]; we subsequently used the calibration curves obtained with that specific matrix to quantify QCs and samples, and corrected the amounts of found GHB by adding the value of the "blank." Obviously, when using the standard addition method, the GHB content of the blank must be recalculated in case calibration curves are prepared with fresh hair.…”

“…sexual assault). Both methods must take into account the physiological concentrations of GHB in human hair, which is an important caveat in forensic cases [12][13][14][15]. The use of hair as a matrix proves particularly valuable when GHB administration is referred or suspected at a later time, as was in a case of a 24-year-old girl who was sexually assaulted [16].…”

Gamma-Hydroxybutyrate (GHB) Content in Hair Samples Correlates Negatively with Age in Succinic Semialdehyde Dehydrogenase Deficiency

“…Patient demographics included 10 patients, age range 3-36 years (median age, 13 years; 9 males), representing approximately 5% of published patients (Malaspina et al 2016). Race as well as hair color can influence the concentration of GHB in hair (Goullé et al 2003). Seven patients resided in the USA, presumed to be of N. European descent.…”

Détermination du GHB dans les poils pubiens par chromatographie gazeuse couplée à la spectrométrie de masse en tandem

“…Celle-ci présente l'avantage de pouvoir mettre en évi-dence le GHB plusieurs semaines après les faits. Les cheveux peuvent être utilisés comme un calendrier historique et permettent de détecter une exposition unique au GHB (3,4). Il n'y a pas de publication à ce jour sur la détection du GHB dans les poils pubiens.…”