Nose-to-brain delivery of TS-002, prostaglandin D2 analogue

This study was conducted to investigate the possibility of performing nose-to-brain delivery of TS-002, which is an analog compound of prostaglandin D₂ (PGD₂) and thus would be a natural sleep inducer. The absolute bioavailability (BA) and sleep-inducing effect (SIE) following intranasal (IN) administration of TS-002 dry powder to cynomolgus monkeys were evaluated in comparison with intravenous (IV) administration. The SIE was evaluated as the accumulated time of sleeping-posture for 3 h. The brain distribution of TS-002 following IN administration of the dry powder was examined in rats. The absolute bioavailability (BA) in monkeys following IN administration of the dry powder (0.4–1.2 mg/body) was comparatively high (43.4–78.0%). The SIE following IN administration (0.05–0.4 mg/body) showed dose-dependency and its effect at 0.4 mg/body was twice as strong as that for IV administration (P < 0.05). The brain concentrations in rats following IN administration (0.1 mg/kg) were obviously higher than that for IV administration at the same dose. The highest content was observed in the olfactory bulb. These results demonstrated that TS-002 was directly transported from the olfactory region to brain, thereby showing that it may be possible to develop a novel sleep-inducing drug based on nose-to-brain delivery.