Pharmacokinetic evaluation of β-caryophyllene alcohol in rats and beagle dogs.

1. β-caryophyllene alcohol (BCPA) has shown therapeutic promise in the treatment of asthma and inflammation with low toxicity. The aim of the current study was to report the pharmacokinetic profiles of BCPA in rats and dogs. 2. Following intravenous administration, BCPA exhibited moderate volumes of distribution (V _z ) ranging from 5.63 to 8.97 L/kg in rats and low V _z (2.89 ± 1.12 L/kg) in dogs. Systemic plasma clearance was high in both species, resulting in a short elimination half-life ranging from 29.6 to 48.3 min. In rats, the intravenous pharmacokinetics was dose dependent. The measured oral bioavailability was low in rats for BCPA solution (1.17 ± 0.78%), suspension (1.21 ± 0.33%) and PEG formulation (6.22 ± 2.63%). The bioavailability was lower in dogs for BCPA solution (0.12 ± 0.05%) and PEG formulation (0.25 ± 0.07%), indicating significant species difference. However, treatment of plasma samples with β-glucuronidase increased the systematic exposure of BCPA as assessed from AUC _(0-∞) by 24.7- or 2.62-fold in rats and dogs, respectively, which suggested glucuronidation was a significant metabolic pathway for BCPA possibly due to first-pass metabolism. 3. In summary, this was the first preclinical pharmacokinetic investigation of BCPA in animals, providing vital knowledge for further preclinical research and subsequent clinical trials.