In vitro permeation studies are commonly performed to evaluate topical formulations aiming skin or mucosal applications. Swine tissues are typically used as biological barriers for these experiments due to its similarities to human tissues. Nasal and sublingual mucosa are promising administration pathways for drug delivery, as consequence of the possibility to obtain local and systemic effect (due to high local vascularization), easy administration, also they avoid first-pass hepatic metabolism and gastrointestinal tract degradation. Ideal conditions for tissue preparation and integrity evaluation have not been well established in the literature yet. It is common to freeze and storage the tissues after preparation, although, these steps facilitate the conduction of the study, they may alter its permeability and integrity, depending on the freezing time and the physicochemical properties of the evaluated drug. The purpose of this study is to define a method of nasal and sublingual mucosa preparation; and to evaluate the possibility of tissue storage (frozen and refrigerated) for use in permeation assays. For this, the preparation method will be defined and the integrity of the mucosa (fresh and after freezing) will be evaluated by electrical resistivity and through conventional and transmission electron microscopy. Thereafter, the results will be submitted to analysis of distribution and homogeneity, and the most appropriate statistical test will be chosen, with significance level of 5%.
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