Bioavailable studies were performed based on plasma concentrations of captopril in 5 Beagle dogs and 5 male healthy volunteers after a single oral administration of captopril sustained-release tablet and sugar-coated tablet. A one-compartment model was adopted. Relative bioavailability of sustained-release tablet to sugar-coated one was 131.6% for dogs and 111.0% for humans. Their mean residence times (MRTs) were 4.52 h and 1.96 h in dogs, 4.28 h and 2.77 h in humans, respectively. The maximum concentrations were 995.9 ng/ml and 2470.8 ng/ml in dogs, 126.2 ng/ml and 251.2 ng/ml in humans for two kinds of tablets, respectively. The duration time, in which plasma concentration staved above 50% inhibitory concentration of angiotensin converting enzyme activity, was more than 10 h for sustained-release tablets and 6h for sugar-coated tablets at the same dose (37.5 mg). consequently, it could be expected that the sustained-release tablet dosed twice a day should have a greater efficiency than marketed sugar-coated tablet taken 3 times daily.

Ketoprofen is widely used as non-steroidal anti-inflammatory drug. A potential sustained release ketoprofen tablet formulation was designed by orthogonal experiment on formulations composed of differential common excipients and homemade polymerides, and was screened by dissolution in vitro. The dissolution rate (%) of the ketoprofen tablet in simulated intestinal fluid was 16.6, 26.7, 42.2, 63.6, 83.1, 93.4, at 30min, 1, 2, 4, 6, 8 h, respectively. The plasma ketoprofen concentrations in six male volunteers were assayed after administration of a single oral dose (100 mg) of the sustained release tablet. It was found that the tablet formulation screened in vitro had sustained release effect in vivo too. This study suggests that there was a close correlation between the dissolution of sustained release ketoprofen tablet in vitro and the percent of dose absorbed in vivo, and the correlation coefficient was 0.9689. The influence of tablet hardness on the release rate of ketoprofen was also observed..