Comparative Serum Estradiol Profiles from a New Once-a-Week Transdermal Estradiol Patch and a Twice-a-Week Transdermal Estradiol Patch

Two identical open-label, randomized crossover studies were conducted to compare serum estradiol profiles from the new 12.5- and 25-cm2 once-a-week adhesive patches with those from the 10- and 20-cm2 commercially available twice-a-week Estraderm patches when applied as directed during a 1-week patch-wear period. Both studies were conducted in healthy postmenopausal women; serum estradiol levels were determined by gas chromatography/mass spectroscopy (GC/MS). Although both sizes of both patch treatments produced mean serum estradiol levels in the therapeutic range, the once-a-week patch provided more constant mean levels, avoiding large peak-to-trough fluctuations. As expected, the differences in mean serum estradiol concentrations between the two patch treatments occurred during the second application of the twice-a-week patch. Based on these results, the once-a-week drug in adhesive patch appears to be an acceptable means of hormone replacement therapy.