Gamma-hydroxybutyrate (GHB), 1,4-butanediol (1,4BD), and gamma-butyrolactone (GBL) intoxication: A state-of-the-art review

γ-hydroxybutyrate (GHB) is synthesized endogenously from γ-aminobutyric acid (GABA) or exogenously from 1,4-butanediol (butane-1,4-diol; 1,4-BD) or γ-butyrolactone (GBL). GBL, and 1,4-BD are rapidly converted to GHB. The gastric absorption time, volume of distribution, and half-life of GHB are between 5 and 45 min, 0.49 ± 0.9 L/kg, and between 20 and 60 min, respectively. GHB and its analogues have a dose-dependent effect on the activation of GHB receptor, GABA-B, and GABA localized to the central nervous system. After ingestion, most patients present transient neurological disorders (lethal dose: 60 mg/kg). Chronic GHB consumption is associated with disorders of use and a withdrawal syndrome when the consumption is discontinued. GHB, GBL, and 1,4-BD are classified as narcotics but only the use of GHB is controlled internationally. They are used for drug facilitated (sexual) assault, recreational purposes, slamsex, and chemsex. To confirm an exogenous intake or administration of GHB, GBL, or 1-4-BD, the pre-analytical conservation is crucial. The antemortem cutoff doses for detection are 5 and 5-15 mg/L, with detection windows of 6 and 10 h in the blood and urine, respectively Control of GHB is essential to limit the number of users, abuse, associated risks, and death related to their consumption.

Determination of endogenous GHB levels in chest and pubic hair

Endogenous nature of GHB represents a critical issue for forensic toxicologists, especially in alleged sexual assaults. Therefore, discrimination between physiologically and additional amounts from exogenous sources of such a substance must be effective and reliable in order to avoid severe misinterpretation. This study aimed to quantify the GHB baseline concentrations in chest and pubic hairs collected from 105 healthy volunteers, non-consumers of any drugs of abuse. The final scope was to investigate if these keratin matrices could represent valid alternative to scalp hair when not available. Moreover, we also evaluated the age and gender influences on the GHB baseline levels. 25 mg of hair were incubated overnight with NaOH at 56 °C. After acidification with H₂SO₄, the solution was liquid-liquid extracted with ethyl acetate and a trimethylsilyl derivatization was then achieved. Analysis was performed in gas chromatography-mass spectrometry in single ion monitoring mode (m/z 233, 234, 147 for GHB; m/z 239, 240 and 147 for GHB-d6). The endogenous amount in "blank" hair was estimated by the standard addition method (0.301 for chest hair and 0.235 ng/mg for pubic hair). GHB concentration ranged from 0.205 to 1.511 ng/mg for chest hair and from 0.310 to 1.913 ng/mg for pubic hair. These values were consistent with previous studies on scalp hair and on pubic hair. Unfortunately, research on chest hair is not available in literature. T-Test and Linear Regression highlighted no statistically significant differences for the two matrices and for all age/gender sub-groups. However, further studies are required to estimate a reliable cut-off value for these keratin matrices. For the first time, we demonstrated the suitability of chest and pubic hair to detect endogenous levels of GHB.