Sistema de liberação controlada baseado em vesículas de poli(estireno-b- óxido de etileno) carregadas com adapaleno inseridas em filmes poliméricos

Abstract

Controlled drug delivery systems are part of the new generation of pharmaceuticals. Because it is a therapeutic system that reduces the risk of intoxication to the patient, causes less discomfort and improves the action of the drug in the body, this has been a very studied area in the development and application of nanotechnology. Polymer vesicles are hollow spherical structures, with nanometric dimensions, capable of penetrating biological barriers, especially in diseased tissues. In this work, the co-solvent technique was applied for the synthesis of vesicles using poly(styrene-b- ethylene oxide) block copolymer, where poly(ethylene oxide) formed the inner and outer layers of the structure and polystyrene formed its membrane. Empty vesicles and vesicles loaded with the membrane-encapsulated hydrophobic adapalene drug were synthesized, which has been used mainly in anti-acne treatments, but is also the object of several studies, for their ability to act in cellular processes, improving their capacity of renewal. The vesicles were characterized by Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and Zeta Potential. Assessments were also made for the presence of post-filtering drug crystals through Polarized Light Microscopy, the presence of the 1,4dioxane solvent in the formulations containing the empty vesicles and loaded with the drug through Fourier Transform Infrared Spectroscopy (FTIR), the content of adapalene encapsulated by the vesicles and their release capacity through Ultraviolet-Visible (UVVis) tests. The obtained vesicles were incorporated into gelatin and collagen together with free Adapalene and silver sulfadiazine. Films were evaluated for their ability to release Adapalene and Silver Sulfadiazine through the in vitro release study, and the collected samples were analyzed through UV-Vis. The obtained results proved the viability of the production of empty and AD-loaded polymer vesicles, although the value of the encapsulated content was less than expected. The results also showed the efficiency of the vesicles in the release of the drug, as well as the films of gelatin and collagen, which presented slightly acidic pH, similar to skin, and are suitable for application as a dressing