COMPARATIVE-STUDY OF THE BIOAVAILABILITY OF BETA-AESCINE AFTER SINGLEORAL-ADMINISTRATION OF 2 DIFFERENT DRUG FORMULATIONS CONTAINING AN EXTRACT OF HORSE-CHESTNUT SEEDS

The relative oral bioavailability of beta-escine (CAS 11072-93-8) from a sugar-coated tablet formulation was compared to a reference prepara tion available in capsule form in 18 healthy, male volunteers over a 4 8 h period. The study design was randomized, single-blind and cross-ov er. Both the test and the reference preparation contained 50 mg standa rdized horse chestnut seed extract; beta-escine was taken as the refer ence substance. By means of a newly developed, validated radioimmunoso rbent assay (RIA), beta-escine in plasma was determined (blind samples ) after oral intake of a single dose of each drug formulation. The con fidence limits calculated for the AUC, C-max and T-max of the test pre paration exceed the upper limit of the specified equivalence range of 80%-125%, but do never fall below the lower limit. Therefore, bioin-eq uivalence cannot be rejected statistically. All the bioavailibility da ta for the test preparation - measured with the newly developed RIA - exceed the corresponding values for the reference preparation. As the rate of absorption of aesculetinic triterpene glycosides is low, the h igher bioavailability of the test preparation is desirable from a ther apeutical point of view. Since the reference preparation is classified as being clinically effective, the test preparation must also be esti mated as being clinically effective. Adverse drug effects were not obs erved with either the test preparation or the reference preparation.