ISSN:
0021-9304
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
,
Technology
Notes:
The derivation and experimental verification of a unified mathematical model for the estimation of drug release rate from drug-polymer composite tablets are presented. Cylindrical coordinates are utilized in the solution of the diffusion equation for a three-dimensional system. The model is applicable to tablets that range from the shape of a flat disk (radius 〉 thickness) to that of a cylindrical rod (radius 〈 thickness). The general solution for the fraction of drug released at a time t is \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{M\left(t \right)}}{{M\left(\infty \right)}} = 1 - \frac{8}{{l^2 a^2 }}\sum\limits_{m = 1}^{10} {\exp \left({ - D\alpha _m ^2 t} \right)\left({\alpha _m ^{ - 2} } \right)\sum\limits_{n = 1}^{10} {\exp \left({ - D\beta ^2 _n t} \right)} \left({\beta _n ^{ - 2} } \right)} $$\end{document} This approach to a three-dimensiona system, utilizing cylindrical coordinates, presents a comprehensive method for the estimation of drug release rates from sustained release tablets with drug distributed homogeneously throughout a polymer matrix. The calculated and experimental drug diffusion rate of pyrimethamine from pyrimethamine-silicone rubber composite tablets that range in shape from that of a disk to a cylinder, and of hydrocortisone from EVA, poly-caprolactone, and PVA terpolymer, are compared.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jbm.820100507
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