<i>In Vitro</i> Drug Release and <i>Ex Vivo</i> Dermal Drug Permeation Studies of Selected Commercial Benzoyl Peroxide Topical Formulations: Correlation Between Human and Porcine Skin Models

<i>In vitro</i> release testing (IVRT) serves as a crucial tool to assess the quality, physicochemical behavior, and performance of semisolid formulations already available on the market. <i>In vitro</i> skin permeation studies (IVPT) are widely used to evaluate the safety and efficacy profiles of topical drugs, utilizing biological membranes prepared from <i>ex vivo</i> human and porcine skin tissues. This study aimed to develop and validate a discriminative IVRT method to evaluate various marketed topical benzoyl peroxide formulations. Additionally, IVPT was employed to assess skin permeation and retention profiles of these formulations, comparing porcine skin results with those obtained by using <i>ex vivo</i> human skin tissues. Physicochemical differences among the evaluated benzoyl peroxide formulations were identified, with the poloxamer-based formulation exhibiting a higher release rate. IVPT using both porcine and human skin differentiated retention and skin permeation profiles, with the poloxamer-based formulation demonstrating greater skin retention capacity compared to the other formulations evaluated. Similar conclusions on benzoyl peroxide retention and cutaneous permeation were drawn from both porcine and human skin IVPT tests, confirming the correlation between the two models.