Abstract

Cannabinoid receptor agonist 13 (CRA13) is a novel cannabinoid (CB) receptor agonist with high affinity and functional activity toward both CB₁ and CB₂ receptors. This phase I study aimed to evaluate the pharmacokinetics, safety, and tolerability of single oral doses of CRA13. Sixty-three of 69 healthy adult males were randomized in seven cohorts (n = 9) to receive 1 to 80 mg of CRA13 or placebo orally in fasted condition. To investigate the diet effect, an independent group (n = 6) was randomized to receive 40 mg of CRA13 after high-fat and high-calorie breakfast in crossover design with a 2-week washout period. Peak plasma concentration (C_max) ranged from 7.8 to 467.6 ng/ml (1–80 mg). CRA13 was rapidly absorbed and demonstrated linear pharmacokinetics (1–80 mg). Time to reach C_max (t_max) was 1.5 to 2 h for all doses in both fasted and fed groups. Administration of 40 mg of CRA13 with food induced approximately 2-fold increase in the C_max and the area under the concentration-time curve, AUC_{0 – tz}. The apparent elimination half-life (t_1/2) was 21 to 36 h and 30 to 41 h for fasted and fed groups, respectively. Dizziness, headache, and nausea were the most frequently reported adverse events (AEs), predominantly at the 40- and 80-mg doses. The incidence of AEs was dose-dependent and mild to moderate. No deaths and serious adverse events were reported. In conclusion, CRA13 was reasonably well tolerated and demonstrated a linear pharmacokinetics over the studied dose range (1–80 mg). Food intake increased CRA13 C_max and AUC_{0 – tz} by approximately 2-fold, whereas t_max was unaffected.