Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/13376
Title: Mechanistic investigations on drug delivery from alginate matrices
Authors: CHING AI LING
Keywords: alginate, cross-linking, pH-modifier, lamination, anisotropy, pH-sensitive
Issue Date: 23-Aug-2007
Source: CHING AI LING (2007-08-23). Mechanistic investigations on drug delivery from alginate matrices. ScholarBank@NUS Repository.
Abstract: This study investigated the influence of various physicochemical properties of alginates on drug release from alginate matrices. The particle size of constituent alginate particles affected the burst release phase in acid media, suggesting its role in the diffusion barrier development. Higher viscosity alginate reduced the rate of alginic acid barrier formation but formed less erodible gel barrier at pH 6.8. Alginate MG ratio influenced matrix integrity. High-G alginate matrices showed greater propensity to crack or laminate at acidic pH compared to high-M alginate matrices. Cracks compromised diffusion barrier integrity and were associated with the protonation of sodium alginate. Incorporation of pH-modifiers caused transient micro-environmental pH elevation which impeded alginate protonation, thus minimizing matrix lamination. Matrices with cross-linked barrier resisted crack development, even with gradual conversion to alginic acid. The dissolution performance of alginate matrix at gastric pH was governed by the preservation of its integrity.
URI: http://scholarbank.nus.edu.sg/handle/10635/13376
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