Journal article
EFFECT OF DRUG CHARACTERISTICS ON THE DEGRADATION RATE OF POLYMERIC MATRICES
Polymer preprints, Vol.48(1)
01 Mar 2007
Abstract
Drug release from biodegradable matrices depends on the composition and geometry of the polymer matrix particle, matrix degradation, drug diffusion in the matrix and solution, drug solubility and metabolization, swelling (water penetration), pore formation, and environmental factors such as osmotic pressure and pH. Current models commonly focus on the effect of polymer type and properties on the release of specific model drug [e.g. 1-5]. However, experiments show that the drug characteristics can significantly affect the release process: Comparing the release rate from the same polymeric matrix, Frank, et al [6] find differences between the base and salt forms of lidocaine. Sung, et al [7] show that the rate of drug release increases, for the prodrugs examined, with hydrophilicity. Similarly, we have shown that the release profile of six different drugs, from the same matrix, differs significantly in their release rate (mg drug/day) [8]. Differences in the rate of drug release may be due to differences in the drug diffusion coefficient, [7]. However, drug properties were shown to affect other processes as well: Proikakis, et al [9] find that incorporation of different drugs in non-degrading polymer matrices affects the degree of swelling. Li, et al [10] show that caffeine incorporation can accelerate the rate of matrix degradation (when compared to the pure polymer). Here we present a diffusion/reaction model for the rate of pellet degradation and the release of drugs in vitro from polymer-drug mixtures, accounting for matrix swelling by water and the effect that has on the degradation process. Thus, our model can describe the entire range of degradation mechanisms, from surface erosion to bulk degradation. And relate that to the properties of the drug.
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Details
- Title
- EFFECT OF DRUG CHARACTERISTICS ON THE DEGRADATION RATE OF POLYMERIC MATRICES
- Creators
- K WernerK MetzgerS SiegelNily Dan
- Publication Details
- Polymer preprints, Vol.48(1)
- Resource Type
- Journal article
- Language
- English
- Identifiers
- 991019312359304721