Bioequivalence in keratolytic activity of formulations vs its vehicle and comparator formulation: randomized, double-blind clinical trial.

This study assessed the bioequivalence, using keratolytic efficacy, of topical preparations studied in humans using adhesive tape stripping and biophysical methods. Ten healthy patients (3 men and 7 women [7 Caucasians and 3 Asians] mean age, 47 years) completed the study. Each coded product was randomly applied to the back according to the designated time of each sample. In addition, an untreated site (normal skin), and an untreated occluded site (chamber only) served as controls. At the end of the application time, each site was rinsed with tap water and then covered with a plastic chamber for 6 hours. Following removal of the chamber, the site was stripped for protein assay and squamometry analysis. This extends previous observations discerning bioequivalence resulting from different active materials with varying mechanism of action and potency on the skin. Results showed no significant difference between tested products. The novel formulations were of equal keratolytic activity to the "standard" (comparator) and hence bioequivalent in keratolytic activity.