Inclusion of hydroxytyrosol in ethyl cellulose microparticles: In vitro release studies under digestion conditions

Abstract

Hydroxytyrosol, existing at high concentrations in olive oil, presents remarkable health benefits mainly due to its antioxidant properties. Nevertheless, the inclusion of hydroxytyrosol in functional foods and pharmaceutical compounds is restricted due to its high hydrophilicity. This study aimed to obtain hydroxytyrosol-loaded microparticles using ethyl cellulose as a carrier. Microparticles were produced by double emulsion solvent evaporation technique considering two theoretical loadings (5 and 10%). Microparticles were obtained and characterized concerning encapsulation efficiency, product yield, wettability, thermal transitions, particle size distribution, morphology and total antioxidant capacity. In vitro release studies were performed using simulated gastrointestinal fluids. Additionally, a morphological degradation analysis was accomplished. The maximum encapsulation efficiency and product yield were 88.1 +/- 0.1% and 82.4 +/- 2.1%, respectively, using the formulation with the lowest loading. Hydroxytyrosol-loaded ethyl cellulose microparticles were nearly stable in a temperature range of 30 degrees C to 280 degrees C. The mean particle size ranged from 156.6 +/- 6.9 mu m to 304.0 +/- 16.0 mu m. The antioxidant capacity retainment remained above 50%. Results demonstrated the effectiveness of gastroresistance of the produced microparticles. The morphological degradation analysis suggested a bulk-to-surface erosion controlling process. The findings of this research indicate the possible application of microencapsulated hydroxytyrosol in foods, drugs, and nutraceuticals.