[Comparison of the relative bioavailability and pharmacokinetics of estrone after oral administration of esterified estrogens in a tablet formulation and an aqueous suspension].
In a two-way crossover study in 18 young female volunteers aged from 22 to 38 years the relative bioavailability and pharmacokinetics of esterified estrogens were investigated after single administration of a sugar-coated tablet formulation (Femavit 1.25) in comparison to a single dose of an oral suspension. The content of active ingredients was in both cases 1.25 mg esterified estrogens. As marker compound the dominating active compound estrone (CAS 53-16-7) was chosen. Estrone in serum was measured using a validated radioimmuno assay. The administration of the test and reference preparation was performed on either day 3-7 of two subsequent menstruation cycles in order to obtain low endogenous hormone levels. The relative bioavailability of estrone from the test preparation, based on the total AUC (AUC under the baseline + AUC over the baseline), was 99.2% (90%-confidence interval 91.8-107.1%) und therefore fulfilled the bioequivalence criterion. After deduction of the baseline-AUC a relative bioavailability of the sugar-coated formulation of 113.9% was found, with a broad 90% confidence interval of 72.5-178.9%, due to a higher variability. The absolute Cmax values were similar (255 pg/ml after tablet administration and 279 pg/ml after suspension), bioequivalence also in regard to Cmax was proven. The value of tmax was 4 h for both preparations.
Degen
J
J
Innovex (Biodesign), Freiburg.
Wölke
E
E
Seiberling
M
M
Thomann
P
P
Völter-Erhardt
H
H
D000328:Adult; D019540:Area Under Curve; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004967:Estrogens / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004970:Estrone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D011863:Radioimmunoassay; D013535:Suspensions; D013607:Tablets
D004967:Estrogens; D013535:Suspensions; D013607:Tablets; D004970:Estrone