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Introduction There is a large variation in cannabidiol (CBD) pharmacokinetics and little information on its bioavailability. This study aims to establish the CBD dose‐exposure relationship and to evaluate the effects of dosage forms, food, and doses on CBD absorption. Methods Single‐dose (range: 5–6000 mg) CBD plasma concentration‐time profiles administered as oral solution (OS), oral capsule (OC), or oromucosal spray/drop (OM) from healthy volunteers were extracted from 15 published clinical studies. A dose‐exposure proportionality assessment was performed, and a population‐based meta‐analysis of CBD pharmacokinetics and systemic bioavailability was conducted with a nonlinear mixed‐effects modeling. A three‐compartment model with a Weibull or zero‐order absorption model was used to describe CBD disposition and absorption kinetics. Dosage form, food, and dose were assessed for covariation. Results Oral solution CBD exposures increased less than proportionally with doses of 750 mg or greater, and bioavailability (6.5% at 3000 mg) decreased with increasing dose. The bioavailability of OC (5.6%) and fed‐state OM (6.2%) were similar, whereas it was lower in fasted‐state OM (0.9%). The Weibull absorption model best described OS, OC, and fed‐state OM profiles. The slowest absorption rate was observed in OS, resulting in a time of maximum concentration of 4.75 hours, followed by fed‐state OM (3.13 hrs) and OC (2.1 hrs). The absorption kinetics of fasted‐state OM was best described by a zero‐order absorption for the duration of 1.71 hours. Conclusion The effects of doses, dosage forms, and feeding status on CBD pharmacokinetics were quantified and should be taken into consideration for dose optimization.

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Trans -3,5,4′-trihydroxystilbene (trans-resveratrol, RES) exhibits very low bioavailability due to extensive conjugative metabolism. Whether RES metabolites exhibit pharmacologic activity is of great interest. The present study aimed at synthesis of monoconjugates of RES – the 3- and 4′ monosulfates (R3S and R4′S), and the 3- and 4′ monoglucuronides (R3G and R4′G). Synthesis, purification, and yield are described. Synthesized metabolites were utilized to develop a sensitive LC-MSn assay for direct quantitation of all analytes. The assay was validated for intra- and inter-day precision and accuracy. Synthesis of RES conjugates and development and validation of a sensitive bioanalytical assay were applied to pharmacokinetic evaluation of RES and its circulating monoconjugates in C57BL mice. The study is a first report of direct quantitation of RES monosulfates and monoglucuronides. These results will aid in characterizing the disposition of RES and its major or active metabolites in vivo.