Bioequivalence of a newly developed 17 beta-estradiol tablet versus an identical reference formulation

Two open-label, randomized studies determined the bioequivalence of a test preparation (Prefest(TM)) of micronized 17 beta -estradiol (E-2, CAS 50-28- 2) tablets as compared with a reference preparation of micronized E-2 table ts in healthy postmenopausal women. In Study 1, 36 fasting subjects receive d 4 test preparation 0.5-mg E-2 tablets in one period and 4 reference prepa ration 0.5-mg E-2 tablets in the other period. In Study 2, 36 fasting subje cts received 1 test preparation 3-mg E-2 tablet in one period and 1 referen ce preparation 2-mg E-2 tablet in the other period. Blood samples were coll ected before and after dosing to determine serum concentrations of E-2, est rone, and estrone sulfate. The 90% confidence intervals for the ratios of m ean C-max and AUC values (test preparation/reference preparation) for all t hree analytes were within the prescribed 80%-125% range of bioequivalence. In conclusion, the test preparation 0.5-mg and 2-mg micronized E-2 tablets are bioequivalent to the respective strength reference preparation microniz ed E-2 tablets.