[Kinetics of a new patch for transdermal administration of 17 beta-estradiol].

A novel patch containing 17 beta-Estradiol exhibits improved kinetic profiles compared to the currently available leading transdermal product. The blood concentrations produced by the newly developed matrix patch are stable over 3 to 4 days, thus avoiding the occurrence of 17 beta-Estradiol peaks in the blood. In an additional clinical study an almost linear relationship could be identified between the patch size (Test patch: 7.25, 14.5 and 29.0 cm2) and the obtained 17-estradiol bioavailability (judged on AUC, cmax, c(ave), Cmin). These results are corroborated by the additional in vitro experiments. An almost constant drug delivery rate of 48 micrograms +/- 15 micrograms/day of 17 beta-Estradiol per 13.85 cm2 patch over 4 days can be detected through excised human skin. No statistically significantly different transdermal flux rates of 17 beta-Estradiol were detected in 3 different batches of the transdermal drug delivery system in vitro. Statistical evaluations were performed with the 3-Way-Anova test on the 0.05 significance level. This newly developed product presents a kinetically optimized transdermal 17 beta-estradiol patch for hormone substitution therapy.