Liposoluble vitamin encapsulation in shell–core microparticles produced by ultrasonic atomization and microwave stabilization

Encapsulation may protect unstable, fat soluble vitamins such as vitamin D2 (ergocalciferol). However, encapsulation by the solvent extraction and/or evaporation techniques can require toxic organic solvents, which greatly increase processing costs. The objective of this study was to evaluate the effect on ergocalciferol encapsulation by a combination of the ionic gelation method with the ultrasonic atomization and microwave drying. Optimization of manufacturing parameters included the addition of pluronic-F127 to the core solution at 1.5% w/w to increase the encapsulation efficiency to nearly 92%, greatly improving performance compared to Tween 80 at 0.5% w/w. Microwave treatment at 230 W promoted the recovery of 100% of the ergocalciferol and reduced drying times to about 30 min, while 690 W degraded 40% of the D2. In contrast, the conventional heating degraded 17% of the ergocalciferol during 12 h of processing. By all the applied methods, microparticles were produced with similar gastoresistance properties of less than 10% release at pH of 1.0, to nearly 100% release at pH of 6.8 and 240 min of dissolution. Analysis showed limited ergocalciferol degradation after 5 months of storage.