Objectives: To compare the local tolerability, adhesion and estradiol delivery of a 5-cm(2) transdermal patch (Estradot), Novartis Pharmaceuticals, Basel, Switzerland) and a 12.5-cm(2) patch (Climara, Berlex Laboratories, Wayne, NJ, USA).
Methods: This was an open-label, randomized, intrapatient, comparative study. One hundred healthy postmenopausal women applied the 50 micro g/day 5-cm(2) patch and the 12.5-cm(2) patch concurrently for 7 days; safety and tolerability were assessed. Twelve women continued to apply the 5-cm(2) and 12.5-cm(2) patches separately for 7 days in a two-way cross-over study, to investigate the reproducibility of estradiol delivery.
Results: The proportion of subjects with a clinically significant erythema score was higher with the 12.5-cm(2) patch. The 5-cm(2) patch had a significantly lower incidence of very slight erythema than the larger patch (21.4% vs. 32.3%; p = 0.0028). Overall erythema scores were 0.22 and 0.41, respectively. More 5-cm(2) patches had > 90% adherence than the 12.5-cm(2) patches (87.5% vs. 82.0%, not significant) and fewer became detached (0.5% vs. 3.0%). Both the patches showed reproducible delivery of estradiol.
Conclusion: The 5-cm(2) patch was associated with less skin irritation and better adherence than the 12.5-cm(2) patch, although the majority of the differences were not significant. The 5-cm(2) patch was well tolerated and showed reproducible estradiol delivery, as did the 12.5-cm(2) patch.