Pharmacokinetic changes of DA-8159, a new erectogenic, and one of its metabolites, DA-8164 after intravenous and oral administration of DA-8159 to spontaneously hypertensive rats and DOCA-salt-induced hypertensive rats

The pharmacokinetics of DA-8159 and one of its metabolites, DA-8164, were compared after intravenous and oral administration of DA-8159 at a dose of 30 mg/kg to spontaneously hypertensive rats (SHRs) at 16 and 6 weeks old and their respective age-matched control normotensive Kyoto-Wistar rats (KW rats), and deoxycorticosterone acetate-salt-induced hypertensive rats (DOCA-salt rats) at 16 weeks old and their age-matched control Sprague-Dawley rats. After oral administration of DA-8159 to 16-week-old SHRs, the AUC values of both DA-8159 (157 versus 103 μg min/ml) and DA-8164 (215 versus 141 μg min/ml) were significantly greater, but the values of DA-8159 were reversed in 16-week-old DOCA-salt rats (125 versus 200 μg min/ml). However, the AUC values of both DA-8159 and DA-8164 were not significantly different between the 6-week-old SHRs and their control rats. The above AUC differences in 16-week-old SHRs may be due to neither hereditary characteristics of SHRs nor the hypertensive state itself.