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Updated: Aug 17, 2026

Ovariectomy and 17β-estradiol Replacement in Rats and Mice: A Visual Demonstration
Published on: June 7, 2012
Comparative serum estradiol profiles from a new once-a-week transdermal estradiol patch and a twice-a-week
L I Harrison1, D J Riedel, S F Chang
1Department of Pharmacokinetics and Drug Metabolism, 3M Pharmaceuticals, St. Paul, Minnesota 55144, USA.
Abstract:
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.
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