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Formation of alginate microspheres produced using emulsification technique
P W S Heng1, L W Chan, T W Wong
1Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543. phapaulh@nus.edu.sg
Journal of Microencapsulation
|July 26, 2003
Summary
This study explores alginate microsphere formation using emulsification. Key factors influencing microsphere size and drug content include calcium salt properties and cross-linking efficiency.
Area of Science:
- * Pharmaceutical Sciences
- * Materials Science
Background:
- * Alginate microspheres are widely used for drug delivery.
- * Emulsification is a common technique for microsphere production.
- * Understanding the formative process is crucial for optimizing microsphere characteristics.
Purpose of the Study:
- * To investigate the formative process of alginate microspheres produced via emulsification.
- * To evaluate the impact of various calcium salts on microsphere properties.
- * To determine how cross-linking parameters affect microsphere size, shape, and drug content.
Main Methods:
- * Alginate microspheres were formed by cross-linking alginate globules in an organic phase using calcium chloride, acetate, lactate, or gluconate.
- * Microsphere size, shape, drug content, and Ca2+ content were analyzed.
- * Properties of the calcium salt solutions (pH, tack, viscosity) and Ca2+ partitioning were measured.
- * Microscopic examination of the emulsion during formation was performed.
Main Results:
- * Microsphere formation resulted from alginate globule clustering, dependent on cross-linking reactions.
- * Higher cross-linking rates, influenced by solution pH, tack, and Ca2+ content, promoted microsphere growth.
- * The order of free Ca2+ cross-linked with alginate was: calcium acetate > calcium chloride + calcium acetate > calcium chloride + calcium gluconate; calcium chloride + calcium lactate > calcium chloride.
- * Microsphere size was modifiable by cross-linking solution properties and combined calcium salts, but shape remained unaffected.
Conclusions:
- * The emulsification process for alginate microspheres is governed by the interplay of alginate and calcium salt globules.
- * Physicochemical properties of the cross-linking solution and the choice of calcium salts significantly influence microsphere characteristics, particularly size.
- * This research provides insights into controlling alginate microsphere formation for optimized drug delivery applications.