[Relative bioavailability of a new spironolactone preparation (author's transl)]

The investigations have been performed to determine the relative bioavailability of canrenon from Acelat 100 capsules in comparison with canrenon from a spironolactone standard preparation available on the German market. This was carried out by comparing the areas under the serum fluctuation curves after oral application of both preparations as well as by urine excretion extrapolated infinitely. The preparations were administered together with a standard breakfast. Subsequently up to 48 h blood was withdrawn from the Vena cubiti. According to a known method serum samples were analysed spectrophotometrically. The data obtained were fitted to an open two-compartment model with the RIP-procedure. The core of the program is a Gauss-Newton iteration (minimising the last squares). These are the results: By intraindividual comparison of the areas under the serum fluctuation curves of canrenon a relative bioavailability of 116.27% (s = 16.84) of canrenon from Acelat 100 could be calculated versus canrenon from the standard. Urine excretion, extrapolated infinitely, showed a 4% higher excretion of canrenon after application of Acelat 100 compared to standard. Both results are not significantly different in the range of biological scattering. The further pharmacokinetic parameters calculated were within the range of the literature available.