Revisiting the influence of emulsion droplets on the distribution of the active material inside spray dried microparticles

Abstract

Abstract The aim of this study was to investigate how an emulsifying agent behaves during the spray drying process. For this, the evolution of droplet size during the emulsion and redispersion in matrix phases were monitored as a function of the process conditions and formulations. The emulsions were prepared using maltodextrin and modified starch (Capsul) as wall materials, and d-limonene as the active compound. The increase in surfactant concentration favored the reduction in size of the oil droplets during the emulsification, atomization, drying and redispersion of the powder processes. A correlation was observed between the size of the oil droplets in the initial and reconstituted emulsion, with the encapsulation efficiency. Reconstituted emulsions with oil droplet sizes below 1 µm, led to encapsulation efficiency above 81.53%. The results confirm that the size of oil droplets in the emulsion and the surfactant concentration directly influences the process and the stability of the microparticles.