A patient-centric liquid chromatography-tandem mass spectrometry microsampling assay for analysis of cannabinoids in human whole blood: Application to pediatric pharmacokinetic study

•Patient-centric volumetric absorptive microsampling approach.•Development and validation of THC, CBD, and CBN assay in human whole blood.•Comparison of human whole blood, plasma and volumetric absorptive microsampling.•Application of the assay for pharmacokinetic analysis of CBD in pediatric clinical samples. Medical cannabis is increasingly used for the treatment of various ailments in children and adults. Three major cannabinoids in cannabis are delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). There is a growing need to develop and utilize a patient-centric blood microsampling methodology to enable clinical trials and facilitate therapeutic drug monitoring. We have employed the volumetric absorptive microsampling (VAMS™) devices that enables accurate and precise collection of a fixed volume (20 µL) of blood, minimizing the impact of hematocriton accurate quantitation. We developed an ultra-performance liquid chromatographic method with tandem mass spectrometry detection for the quantification of three cannabinoids (THC, CBD, and CBN) employing deuterium labelled internal standards (THC-D3, CBD-D3, and CBN-D3). Sample extraction of VAMS™ devices, followed by solid phase extraction, reverse phase chromatographic separation, and selective detection using tandem mass spectrometry with a 6-minute runtime per sample was developed. Standard curves were linear between 1 and 500 ng/mL for THC and 0.5–500 ng/mL for CBD and CBN. Intra-day accuracies were within 91.3–112% while inter-day accuracies were within 94.4–107% with both having precisions (CV (%)) of