A Phase I Trial of the Safety, Tolerability, and Pharmacokinetics of
Cannabidiol Administered as Single-dose Oil Solution and Single and
Multiple doses of a Sublingual Wafer in Healthy Volunteers
Abstract
Aims: This study investigated the safety, tolerability, and PK after
administration of a specific Cannabis sativa cultivar extract,
standardised to CBD content as sublingual wafer or oil formulation
compared to nabiximols oromucosal spray. Methods: For the single-dose
study, the design was an open-label, four-way crossover in 12 healthy
volunteers randomised to receive a sequence of four different single
doses of CBD as a sublingual wafer (25 or 50 mg CBD), oil solution (50
mg CBD), or nabiximols oromucosal spray (20 mg CBD, 21.6 mg THC). For
the multiple-dose study, sublingual wafer (50 mg CBD) was administered
twice a day for five days. Results: The extract was generally well
tolerated by participants when administered in either wafer or oil form,
with some adverse events, including mild or moderate somnolence,
sedation and altered mood. The relative bioavailability of CBD after
administration as a sublingual wafer was comparable with that of oil
solution with 90% confidence interval of 83–131%. The median maximum
concentrations of CBD after administration of oil solution and wafer was
9.4 and 11.9 ng mL-1, respectively. Maximum concentrations of CBD
occurred 4 hours after administration, with an estimated terminal
elimination half-life of 6 hours. There was no statistically significant
difference between the AUC0-t of CBD after administration of oil
solution or wafer compared with nabiximols oromucosal spray. Conclusion:
Oil solution and sublingual wafer formulations of the extract
standardised with CBD were well tolerated and demonstrated safe and
achieved equivalent concentrations of CBD when compared to an available
commercial formulation.