Desenvolvimento e caracterização de micropartículas lipídicas sólidas à base de cera de carnaúba e ácido kójico

Abstract

Hyperpigmentation is a common skin problem and gives the skin an aged and unever appearance. Excessive exposure to sunlight without protection is one of the causes of hyperpigmentation. In Brazil, kojic acid is widely applied in dermocosmetic formulations as depigmentation agent, and this work aims at the development and characterization of solid lipid microparticles (SLM) for differentiated serving of kojic acid, using as lipid matrix wax carnauba and Tween 80 as surfactant. The SLM were produced by hot homogenization method using high agitation (Ultra Turrax®). For improve the encapsulation efficiency of the hydrophilic active through this method, was evaluated the change in the proportion active/lipid matrix, speed and time of agitation during the production process. The characterization of the SLM was made through the analysis of morphology by microscopy, the yield of the process, the encapsulation efficiency and the release of the active profile. The SLM showed spherical shape and heterogeneity in their sizes. In the process yield analysis results varied between 64 and 87%, where it was observed that there is an inverse relationship between the yield of the process. The results of effective encapsulation efficiency are between 5 and 15%. These results may be related to the method, the type and concentration of surfactant used in the formulation, where the stirring speed is directly proportional to the encapsulation efficiency of the active, the fact that the lipid matrix is composed of a single lipid and the hydrophilic nature of the active. The release profile of kojic acid expresses a slow and gradual release of 41% in 6 hours, a result that the modified release character.