Formação e caracterização de organogéis para veiculação de vitamina E

Abstract

Topic drug administration is a non-invasive, easy and advantageous route for the absorption of an active ingredient in the body. As well as in the pharmaceutical area, the cosmetics industry uses this material transfer mechanism in order to prevent degradation caused by interactions with other compounds before absorption through the skin. Among the variety of bioactive delivery systems, organogels have stood out as materials with an attractive structure for the controlled release of bioactive compounds. These materials are semi-solids formed by the mixing of small concentrations of gelator (<15 %) and organic solvent. In parallel, an active compound of interest in these areas is vitamin E, an important fat-soluble nutrient, which has antioxidant, humectant and emollient properties, to name a few. In this context, this study aims to prepare and characterize organogels for the delivery of vitamin E for applications in the cosmetics and pharmaceutical industry. Coconut oil (OCO), canola oil (OCA) and oleic acid (AO) were investigated as organic solvents, whereas Tween 80 (T80) and PEG 300 (P300) were investigated as gelators. Firstly, the phase behavior of the systems was studied, and the pseudoternary diagrams were constructed. Next, vitamin E was incorporated into the gels, and these formulations were characterized through particle size distribution, pH and rheology analyses, and the stability and potencial for vitamin E delivery through the gels were evaluated. Finally, the possibility of quantifying vitamin E in the formulations was assessed using the UV spectrophotometry technique. Based on the solubility tests of binary mixtures of gelator and organic solvent, T80 was the selected gelator for the continuation of the study. Then, the ternary phase diagrams of the OCO/T80/water, OCA/T80/water, and AO/T80/water systems were obtained. Subsequently, the gels obtained with the lower concentration of T80 in each system were characterized. The analysis of particle size distribution, pH and the rheological study indicated that the evaluated formulations are promising, as they exhibit the desired characteristics for cosmetic applications and the delivery of vitamin E. Lastly, UV spectrophotometry was not suitable for quantifying the incorporated vitamin E in the gels due to interference caused by the absorption of UV radiation by the excipients at the same wavelength as vitamin E.