Volumetric absorptive microsampling for in vitro metabolism of the recent synthetic cannabinoid receptor agonist 5F-PB-22

• VAMS microsampling was applied for the first time to in vitro 5F-PB-22 metabolism. • Pig microsomes were used as a model of human hepatic metabolism. • Quantitation of 5F-PB-22 and its main metabolite was carried out. • The complete analytical workflow was validated within international guidelines. • VAMS demonstrated to be stable at RT in a simulated shipping scenario. New Psychoactive Substances (NPS) are an emerging class of drugs of abuse, which includes a large number of illicit substances belonging to various classes, with widely different chemical and pharmacological properties. Thus, detailed information on their properties is still lacking or debated. In the first part of this study, GC–MS was applied to the identification of 5F-PB-22, a synthetic cannabinoid receptor agonist (SCRA), and related substances in seized material. In the second part, the in vitro metabolism of 5F-PB-22 was investigated by the innovative application of volumetric absorptive microsampling (VAMS), a miniaturised sampling and sorbent-based extraction technology usually applied to blood. After addition of the analyte and incubation, porcine liver microsome supernatants were sampled and extracted using VAMS. After drying and simulated shipping, microsamples were extracted and analysed by an HPLC-MS/MS method, developed and validated for this purpose (linearity 2–1500 µg/mL, precision RSD < 9.3 %, accuracy > 88 % for all analytes). The developed VAMS methodology has proven to be a suitable approach to the investigation of synthetic cannabinoid metabolism, using minute amounts (20 µL) of sample, providing reliable results and also ensuring suitable stability (maximum loss 6.6 % over 7 days at room temperature) for courier shipping to other locations without refrigeration/freezing.