Drug encapsulation in alginate microspheres by emulsification

Abstract

A method based on an emulsification process was developed for the production of calcium alginate microspheres. Isopropyl alcohol and acetone, which are strong dehydrating agents, were used to aid in the hardening and drying of the microspheres. However, the amount of drug encapsulated was very low. This was due to the drug being soluble in the dehydrating solvents. In the absence of the solvents a high percentage of drug was encapsulated, and this was further increased by forming the microspheres by phase inversion. It was also found that a suspension of the drug particles was required for effective microencapsulation. The efficiency of drug encapsulation generally increased with the ratio of drug to encapsulating material. The microspheres produced were free-flowing and most of them were smaller than 150 microns.

Microencapsulation of hemoglobin in chitosan-coated alginate microspheres prepared by emulsification/internal gelation

“…Uncoated microspheres formed a fi lm, and clumps of microspheres were formed for coated microspheres, probably owing to cohesion of the initially wet microspheres. 31 Lyophilized microspheres presented a sponge-like structure.…”

Stabilization of glucose oxidase in alginate microspheres with photoreactive diazoresin nanofilm coatings

“…Alginate gel microspheres were prepared by a method adapted from previous reports (Wan et al, 1992(Wan et al, , 1993(Wan et al, , 1994(Wan et al, , 2003 for encapsulation of macromolecules as illustrated in Figure 1a. The preparation of the alginate microspheres using an ultrasonicator is to obtain smaller microspheres (typically <10 mm).…”

Microencapsulated probiotics using emulsification technique coupled with internal or external gelation process

“…Extrusion technique is widely used at lab-scale for scientific research because of low yield, while emulsification technique has a potential for large-scale production of the beads in shorter time (Takei, Yoshida, Hatate, Shiomori, & Kiyoyama, 2009), which is essential for commercial application. For emulsification/external gelation technique, polysaccharide aqueous solution is dispersed in oil phase to form W/O emulsion, and calcium chloride solution is then added at stirring for gelation and encapsulation of probiotics (Homayouni, Azizi, Ehsani, Yarmand, & Razavi, 2008;Mokarram, Mortazavi, Najafi, & Shahidi, 2009;Wan, Heng, & Chan, 1992). However, the disruption of the emulsion system equilibrium may cause a significant clumping of microcapsules (Poncelet, Babak, Dulieu, & Picot, 1999) before properly hardening.…”