Spray-drying of oil-in-water emulsions for encapsulation of retinoic acid: Polysaccharide- and protein-based microparticles characterization and controlled release studies

Oil-in-water emulsions were proposed to produce retinoic acid (RA)-loaded biopolymer-based delivery systems applying spray-drying technology. They were characterized regarding rheological properties (i.e. viscosity), stability and droplet size distribution. The usage of a spray-dryer inlet air temperature of 130 degrees C significantly increased RA encapsulation efficiency for modified chitosan-based microparticles. Empty and oil-loaded (with and without RA) microparticles were produced with a product yield between 12 and 41%. Microparticles with a mean diameter from 1.712 +/- 0.004 and 12.9 +/- 0.3 mu m were produced, as well as with a morphology that varied from a very smooth to a high rough surface structure. The time required for the complete RA release from microparticles to the surrounding environment (octanol) - release time - varied according to the biopolymers used in the microparticles formulations. The faster RA controlled release was registered from microparticles composed by xanthan and arabic gums (48 and 94 min, respectively). In turn, alginic acid sodium-based microparticles enabled to increase the RA release time for almost 8 h.

Automated summary

Oil-in-water emulsions were utilized to produce RA-loaded biopolymer-based delivery systems using spray-drying technology, with different rheological properties and droplet size distributions. The use of a spray-dryer at an inlet air temperature of 130 degrees C significantly improved RA encapsulation efficiency in modified chitosan-based microparticles. The release time of RA from microparticles varied depending on the biopolymers used, with xanthan and arabic gums showing faster release (48 and 94 min, respectively) and alginic acid sodium prolonging the release time to almost 8 hours.