Urinary excretion and effects on visual placing response in mice of gamma-valero-lactone, an alternative to gamma‑hydroxy-butyrate for drug-facilitated sexual assault

Γ-Valero-lactone (GVL) is a freely marketed organic solvent and food additive. GVL is also an underrated legal substitute for γ-hydroxybutyric acid (GHB), and it is sold under the trade name "Tranquili-G". GVL is usually not included in forensic drug testing, even though it has been reported in drug-facilitated sexual assaults (DFSA). To date, few studies verified the effectiveness of GVL as a hypnotic/narcotic substance, and no data are available on its urinary excretion profile. This work aims to fill this knowledge gap and lead to the introduction of GVL in forensic drug testing, especially when DFSA is suspected. To monitor the timeframe of GVL activity in vivo, we have assessed the effects on sensorimotor responses in visual placing tests carried out on CD-1 mice at a dose of 400 mg/kg of GVL, administered by gastric gavage. In parallel, samples of the in vitro and in vivo metabolism studies were analyzed using a rapid and cost-effective analytical procedure based on gas chromatography coupled to mass spectrometry. Our data confirmed that GVL impairs visual placing response in mice in the first 4 h after the intake, and they also show that GVL is a less potent substitute of GHB. The urinary excretion profile of GVL is consistent with the results of the behavioral study, with a maximum of excretion in the first 5 h after the intake. GVL is only detectable in the first 0–8 h after the intake. Our data confirmed the same rapid urinary excretion rate of GHB in urine and the related forensic implications, with the risk of possible false-negative results, especially when DFSA is suspected.