Recently, a series of KNI compounds such as
KNI-227 and
KNI-272 has been synthesized and shows potent and selective
HIV-1 protease inhibitory activity in vitro. In this study, we developed an HPLC assay system for
KNI-227 and
KNI-272 in rat plasma and examined the pharmacokinetic characteristics in rats after both intravenous (i.v.) and intraduodenal (i.d.) administrations to obtain the disposition characteristics and bioavailabilities of these new
anti-AIDS drugs. After i.v. administration of
KNI-227, 10.0 mg kg-1, the mean terminal elimination half-life, t1/2 lambda zeta, was 0.808 +/- 0.161(SE) h, the total body clearance, CLtot, was 11.7 +/- 3.3 ml min-1 and the distribution volume at steady state (Vd,ss) was 1410 +/- 460 ml kg-1. On the other hand, after i.v. administration of
KNI-272, 10.0 mg kg-1, t1/2 lambda zeta was 2.86 +/- 0.78 h, CLtot was 15.3 +/- 1.4 ml min-1 and Vd,ss was 3440 +/- 670 ml kg-1. In the case of the i.d. administration of drugs, the mean peak plasma concentrations, Cmax, of
KNI-227 and
KNI-272 were 0.374 +/- 0.110 microgram ml-1 and 0.900 +/- 0.093 micrograms ml-1, respectively. The bioavailabilities (BA) of
KNI-227 and
KNI-272 to infinity, BA(0-infinity), were 5.90% and 42.3%, respectively. As compared with the lead compound,
KNI-174, the BA of
KNI-272 was improved about 10 times. Although the anti-AIDS virus activity of these two drugs has not been investigated in vivo,
KNI-272 is expected to be a better candidate for oral anti-
AIDS therapies.