Levels of GHB in hair after regular application

Gamma hydroxybutyrate (GHB) is a central nervous system depressant that is an approved drug for the treatment of narcolepsy with cataplexy and other syndromes. Due to its dose dependent stimulating, relaxing or sedative effects, illicit abuses include recreational use by young people and cases of drug-facilitated crime (DFC). Since GHB is also produced endogenously, for forensic questions, it is important to be able to differentiate between endogenous GHB and elevated levels due to additional intake. In this study, we measured GHB concentrations in hair of patients with narcolepsy receiving daily GHB treatment. The results were compared to endogenous concentrations and concentrations after chronic intake presented in several former studies. The aim of this study was to investigate whether a regular intake of a known dosage of GHB leads to elevated levels of GHB concentration in hair. We collected hair samples of 19 patients (14 female, 5 male) with narcolepsy under regular GHB treatment and examined the hair samples segmentally by digestion of the hair followed by liquid-liquid extraction and analysis using a Shimadzu LC20 UFLC system coupled with an AB Sciex API 4000 Qtrap tandem mass spectrometer. All volunteers received daily treatment with different doses of sodium oxybate (sodium salt of GHB) ranging between 3 and 9g per night. The observed mean value of GHB concentration in hair was 2.69ng GHB per mg hair for the 5 male participants, 1.56ng/mg for the 14 female participants giving an overall mean value of 1.86ng/mg for all participants. Our results showed no correlation between the daily dose or the duration intake of GHB and the measured concentration of GHB in hair. Although we did find a significant (p<0.01) difference between published endogenous levels of GHB in hair and GHB levels in hair of patients with regular daily GHB intake, the forensic relevance however is disputable. We hypothesise this narrow margin or even overlap to be the reason why analytical results from hair analysis in some cases fail to provide a reliable prove of a single exposition.

Detection of γ-hydroxybutyric acid-related acids in blood plasma and urine: Extending the detection window of an exogenous γ-hydroxybutyric acid intake?

In crimes facilitated by γ-hydroxybutyric acid (GHB) administration, the frequent occurrence of anterograde amnesia of the victims as well as the short detection window and variations of endogenous GHB concentrations complicate obtaining analytical proof of GHB administration. Because elevated endogenous organic acid concentrations have been found in the urine of patients with succinic semialdehyde deficiency (leading to accumulation of GHB in human specimens) and after GHB ingestion, we searched for an alternative way to prove GHB administration via detection of elevated organic acid concentrations in blood plasma and urine. We collected blood and urine samples from narcolepsy patients (n = 5) treated with pharmaceuticals containing GHB sodium salt (1.86-3.72 g GHB as free acid per dose). Although GHB was detectable only up to 4 h in concentrations greater than the commonly used cutoff levels in blood plasma, 3,4-dihydroxybutyric acid (3,4-DHB) could be detected up to 12 h in blood plasma in concentrations exceeding initial concentrations of the same patient before GHB ingestion. Furthermore, four of the five patients showed an increase above endogenous levels described in the scientific literature. In urine, GHB concentrations above commonly used cutoff levels could be observed 4.5-9.5 h after GHB intake. Creatinine standardized initial concentrations were reached again for glycolic acid (GA), 3,4-DHB, and 2,4-dihydroxybutyric (2,4-DHB) acid at 6.5-22, 11.5-22, and 8.5-70 h after GHB intake, respectively. Therefore, 2,4-DHB, 3,4-DHB, and GA are promising and should be further investigated as potential biomarkers to prolong the detection window of GHB intake.

Screening and confirmation methods for GHB determination in biological fluids

The purpose of this review is to provide a comprehensive overview of reported methods for screening and confirmation of the low-molecular-weight compound and drug of abuse gamma-hydroxybutyric acid (GHB) in biological fluids. The polarity of the compound, its endogenous presence, its rapid metabolism after ingestion, and its instability during storage (de novo formation and interconversion between GHB and its lactone form gamma-butyrolactone) are challenges for the analyst and for interpretation of a positive result. First, possible screening procedures for GHB are discussed, including colorimetric, enzymatic, and chromatography-based procedures. Confirmation methods for clinical and forensic cases mostly involve gas chromatography (coupled to mass spectrometry), although liquid chromatography and capillary zone electrophoresis have also been used. Before injection, sample-preparation techniques include (a combination of) liquid-liquid, solid-phase, or headspace extraction, and chemical modification of the polar compound. Also simple "dilute-and-shoot" may be sufficient for urine or serum. Advantages, limitations, and trends are discussed.

Injection port silylation of γ-hydroxybutyrate and trans-hydroxycrotonic acid: conditions optimisation and characterisation of the di-tert-butyldimethylsilyl derivatives by GC-MS

Silylation is usually carried out on γ-hydroxybutyrate (GHB) for its analysis by Gas Chromatography/Mass Spectrometry (GCMS) and requires potentially long incubation times before injection during which the derivatisation reagent and derivatives (such as trimethyl-silyl compounds) can hydrolyse. Moreover, alternative internal standards (IS) are often useful depending on sample matrices, extraction/purification procedures, commercial availability and price. This study evaluated the possibility of silylating GHB with an injection port derivatisation procedure using N-methyl-N-[tert-butyldimethyl-silyl]trifluoroacetimide (MTBSTFA) with 1% tert-butyldimethylchlorosilane (TBCS) as the derivatisation reagent, producing di-tert-butyldimethyl-silyl derivatives as a novel means of analyzing GHB. In parallel, trans-hydroxycrotonic acid (t-HCA) was investigated as a potential IS for GHB quantification. Analyses were carried out with a temperature programmable injector and the GHB(t-BDMS)(2) and t-HCA(t-BDMS)(2) derivatives were successfully produced, characterised and derivatisation conditions optimised. t-HCA behaved very similarly to GHB through the derivatisation processes and was used as the IS for the determination of urinary endogenous GHB concentrations in human subjects where the method showed a limit of detection of 0.049 μg mL(-1), a limit of quantification of 0.162 μg mL(-1), and a limit of confirmation of 1.33 μg mL(-1), suitable for toxicological GHB concentration determination.

Dried blood spot punches for confirmation of suspected γ-hydroxybutyric acid intoxications: validation of an optimized GC–MS procedure

Background: γ-hydroxybutyric acid ( GHB ), notorious as a club- and date-rape drug, was quantified in dried blood spots (DBS) by punching out a disc, followed by ‘on-spot’ derivatization and analysis by GC–MS. Results: A homogenous distribution in DBS was demonstrated and accurate results were obtained when analyzing a disc punched out from a 20–35 µl spot, regardless the hematocrit of the blood sample. Validation based on US FDA and European Medicines Agency guidelines was performed, with a calibration range covering 2–100 µg/ml. Conclusion: A sensitive GC–MS method for GHB analysis in DBS was successfully optimized and validated. The successful analysis of DBS collected from GHB abusers suggests the routine applicability of the DBS sampling technique for GHB analysis in toxicological cases.

Acute toxicity and withdrawal syndromes related to γ-hydroxybutyrate (GHB) and its analogues γ-butyrolactone (GBL) and 1,4-butanediol (1,4-BD)

Gamma-hydroxybutyrate (GHB) has been used as a recreational drug since the 1990s and over the last few years there has been increasing use of its analogues gamma-butyrolactone (GBL) and to a lesser extent 1,4-butanediol (1,4BD). This review will summarize the literature on the pharmacology of these compounds; the patterns and management of acute toxicity associated with their use; and the clinical patterns of presentation and management of chronic dependency associated with GHB and its analogues.

Retrospective drug detection in cases of drug-facilitated sexual assault: challenges and perspectives for the forensic toxicologist

Reported incidences of drug-facilitated sexual assault (DFSA) are on the increase worldwide. These cases represent a particular challenge for the forensic toxicologist due to the difficulty in obtaining adequate evidence of drug administration. Primarily, this is due to the nature and diversity of the drugs involved, their pharmacology and sampling timescales. Evaluating whether a drug has been administered to a victim for the purpose of sexual assault can often be difficult, if not impossible. This review draws attention to this burgeoning crime and focuses on the unique challenges DFSA cases present in terms of evidential analysis. Current analytical methodologies for investigating DFSA are highlighted and discussed along with developments in improving analytical procedures. In particular, enlarging detection windows by adopting emerging LC–MS techniques is also discussed. This review also highlights the use of cutting-edge technologies such as ultra-HPLC and the use of alternative matrices for addressing the problem of improved retrospective drug detection.