Predictability of intranasal pharmacokinetics in man using pre-clinical pharmacokinetic data with a dopamine 3 receptor agonist, PF-219061

(R)-3-(4-propylmorpholin-2-yl) phenol (PF-219061) is a potent, selective agonist of the dopamine 3 receptor for the treatment of female sexual dysfunction. In vivo, PF-219061 exhibits liver blood flow clearance in both rat and dog. Oral bioavailability was 0.7% in dog and less than 5% in rat. Intranasal dosing was investigated to improve bioavailability. Pre-clinical assessments in rat and dog demonstrated intranasal bioavailabilities of 16-38% in rat and 54-61% in dog with very rapid absorption. It was predicted that an intranasal dose in man would give approximately 25-50% bioavailability. The clinical data verified the preclinical predictions demonstrating rapid absorption and approximately dose-proportional increases in exposure. The intranasal bioavailability in man was estimated to be 26-38%. These findings indicate the potential utility of intranasal dosing as a route that circumvents the first-pass effects for PF-219061 resulting in high exposures.