[Comparative studies on the bioavailability of various drug forms of phenylbutazone and clofezone (Perclusone)]

The bioavailability (BA) of phenylbutazone and clofezone preparations had been determined in patients suffering from rheumatic diseases. Clofezone is a compound preparation of phenylbutazone and clofexamide, with which the phenylbutazone portion amounts to 49%. In spite of an equivalent dosage (0.4 g phenylbutazone or 0.8 g clofezone, resp.) significant differences in the phenylbutazone-serum level profile had partly been stated after the application of different kinds of the preparation of both the drugs. The oral administrations (phenylbutazone dragées, Perclusone capsules) resulted in a prompt resorption; the plateau values of the phenylbutazone concentration in serum had already been completed after 2-3 h. The resorption from suppositories was decreased. The serum level maximum with phenylbutazone suppositories occurred after 6 h, with Perclusone suppositories after 24 h only. Compared to the phenylbutazone i.v. injection, the phenylbutazone dragées proved a complete substance uptake into the systemic circulation, whereas a relative BA of 65% has been determined for Perclusone capsules. The BA of the phenylbutazone suppositories amounted to 67%, those of the Perclusone suppositories to 41%.