Once and twice a week transdermal estradiol delivery systems: clinical efficacy and plasma estrogen levels

We compared the clinical efficacy and circulating estrogen levels from two transdermal delivery systems, 'drug-in-adhesive' type, in 20 healthy postmenopausal women. Both patches, developed by Beta Pharmaceutical Laboratories in Argentina, deliver estradiol at a rate of 50 micrograms/day; the replacement frequency of system A (TrialSat) was twice a week and for system B (TrialSat LA) once a week. The women were treated for 180 days, in a continuous regimen, with additional oral medroxyprogesterone acetate 5 mg/day for 14 days of each cycle. Blood samples were taken at the end of the wearing period: the 3rd day for Group A and the 7th day for Group B, to determine levels of estradiol, estrone, non-sex hormone binding globulin (SHBG)-bound estradiol and SHBG. Both treatments had similar clinical efficacy and were well tolerated. Plasma estradiol levels were higher in Group A throughout the study, probably owing to the different sampling times. SHBG and non-SHBG-bound estradiol were unchanged in both groups. As there was a similar performance of both delivery systems, the 7-day patch may be preferable, and produce greater compliance.