Direct Monitoring of Exogenous γ-Hydroxybutyric Acid in Body Fluids by NMR Spectroscopy

Abstract

ABSTRACTγ-Hydroxybutyric acid (GHB) is a popular drug increasingly associated to cases of drug-facilitated sexual assault (DFSA). Currently, expanding procedures of analysis and having forensic evidence of GHB intake at a long term are mandatory. Up to now, most studies have been performed using GC-MS and LC-MS as analytical platforms, which 25 involve significant manipulation of the sample and, often, indirect measurements. In this work, procedures used in NMR-based metabolomics were applied to a GHB clinical trial on urine and serum. Detection, identification and quantification of the drug by NMR methods were surveyed, as well as the use of NMR-based metabolomics for the search of potential surrogate biomarkers of GHB consumption. Results demonstrated the suitability of NMR 30 spectroscopy, as a robust nondestructive technique, to monitor (detect, identify and quantify) fast and directly exogenous GHB in almost intact body fluids, and its high potential in the search for metabolites associated to GHB intake.

Identification of new urinary gamma‐hydroxybutyric acid markers applying untargeted metabolomics analysis following placebo‐controlled administration to humans

“…While present in both treatment groups, glycolate and succinylcarnitine significantly increased in concentration due to GHB administration. Palomino‐Schätzlein et al recently also observed significant concentration increases of glycolate and succinate in urine samples after controlled GHB administration . While succinate itself was not identified in the current study, an increase in succinylcarnitine, the carnitine conjugate of succinate was observed as a follow‐up metabolite of succinate.…”

“…This approach can also help by giving insights about the pathways implicated in the mechanism of drug action, adverse effects and variability of the drug response . A few metabolomic studies have been performed in order to further evaluate the underlying mechanisms of GHB's pharmacological action or to finally find useful biomarkers of its consumption . For example, Luca et al found up to 7‐fold higher levels of glycolate – originating form β‐oxidation of GHB – in brain and liver of mice .…”

“…For example, Luca et al found up to 7‐fold higher levels of glycolate – originating form β‐oxidation of GHB – in brain and liver of mice . Also Palomino‐Schätzlein et al observed significant increases in glycolate as well as succinate in urine following controlled administration of GHB to humans using nuclear magnetic resonance (NMR)‐based metabolomics . Piper et al applied mass spectrometry (MS)‐based metabolomics while searching for endogenous urinary metabolites potentially correlating with the urinary excretion of GHB‐sulfate and GHB‐glucuronide in order to find a suitable marker to normalize urinary concentrations …”

Analytical considerations for (un)‐targeted metabolomic studies with special focus on forensic applications

“…13 So far, few studies have focused on drugs of abuse (DOA) [14][15][16][17][18] and many of those were performed on mice and rats. Biomarker research can be used for acute or chronic drug consumption to investigate consumption behavior or to find underlying toxicological aspects of its action in humans.…”

“…16:0 (1-palmitoyl-2-hydroxy-sn-glycero-3-phosphocholine); lyso PC 18:1 (1oleoyl-2-hydroxy-sn-glycero-3-phosphocholine/lysoPC (18:1 (9Z))); lyso PE 18:arg, azelaic acid, CDA, CA, citrulline, col, con, crea, DCA, GluA, GlyA, HA, ino, ile, leu, L-pyroglutamic acid, met, MetMA, mevalonolactone, N,N-dimethylglycine, nicotinic acid, p-aminobenzoic acid, phe, pro, raffinose, riboflavin, taurine, TA, trp, and uracil (concentration 10 μg/mL each) was measured in the beginning, middle, and at the end of each measurement method and checked for reproducibility of the data by retention time (RT) shifts and peak area comparison using MultiQuant V 2.1 (Sciex, Concord, Ontario, Canada).…”