Repeated oral once daily intake of increasing doses of the novel synthetic genistein product Bonistein in healthy volunteers.

Bonistein is a new product consisting of > 99.5 % synthetic genistein, an isoflavone with phyto-oestrogenic properties, which might be a safe and efficacious alternative for the prevention of post-menopausal bone loss to the traditional hormone replacement therapy. A randomised, open-labelled and sequential-group phase I study was performed to assess safety, tolerability and pharmacokinetic characteristics of oral administrations of Bonistein. Thirty healthy volunteers received in three subsequent groups 30, 60 or 120 mg once daily for 14 days. For the pharmacokinetic profiles of Bonistein, blood samples were taken on study Days 1 (after first dose) and 14 (steady state). Repeated intake of Bonistein was well tolerated. A total of 33 adverse events were reported, mainly of mild intensity. No relevant changes in clinical laboratory or vital signs were observed. The pharmacokinetic characteristics of Bonistein revealed comparable results for extent and rate of absorption on Days 1 and 14. Both AUC and C (max) values of Bonistein increased in proportion with the dose.