Design and characterization of controlled-release vitamin A microparticles prepared by a spray-drying process

Abstract

Vitamin A has been incorporated for the development of new products with applicability in food, pharmaceutical and cosmetic fields. Some research lines are focused in the preparation of food fortification and in the creation of enteral formulas. Moreover, the literature highlights the effect of vitamin A and other retinoids on anti-aging treatments. In fact, vitamin A plays a number of key roles in the human body, this micronutrient is involved in vision, reproduction, cellular growth and differentiation, embryonic development, epithelial cellular integrity and immunological activity. However, the poor solubility in aqueous systems, low polarity and very high sensitivity of vitamin A are the main concerns that need to be overcome during processing and storage. Microencapsulation technology may provide the required protection and stabilization of vitamin A, preventing or reducing its degradation.In the present work, microencapsulation of vitamin A (retinol) was studied using the spray-drying technology. Five concentrations of encapsulating agent were assessed (2, 5, 10, 15 and 20% (w/V) of arabic gum) and for each one a fixed amount of vitamin A (2% (w/V)) dissolved in coconut oil was used. The effect of coconut oil in the microparticles was also evaluated with the production of coconut oil microparticles (without vitamin A) and empty microparticles (without coconut oil and without vitamin A).The product yield obtained for the microparticles with coconut oil (with and without vitamin A) ranged from 13.6 to 28.6%, while for the microparticles only composed of arabic gum it was around 67%. For the different formulations of reagents investigated the microparticle size was between 3.473 and 10.400μm. Regarding the surface structure, all microparticles showed spherical form and rough surfaces. Vitamin A release studies were performed and validated by a UV/VIS spectrophotometer using absorbance analysis. The results showed that only microparticles with 15 and 20% (w/V) of arabic gum were able to ensure the complete protection and consequent stabilization of vitamin A, being registered the release of initial total amount of vitamin A. The usage of lower concentrations of encapsulating agent probably resulted in a non-robust network, which compromised the microparticles function. Moreover, the cumulative vitamin A release profiles obtained for all concentrations of arabic gum investigated were similar. The vitamin stability was observed for at least one month. This study proves the success of the vitamin A (retinol) microencapsulation using the spray-drying technique.