Mathematical Modeling of Drug Release from Spherical Drug Particles: Analysis of the Effect of Absorption Rate on Drug Release Rate

A closed form solution has been obtained for the release kinetics of a solute from a spherical drug matrix into a finite volume of liquid, taking into account the effect of rate of absorption. The proposed model results clearly show the effect of the absorption rate constant on the rate of drug release. The obtained results are compared with the experimental data and diffusion-only model results. There is a significant difference in the release profile when the rate of absorption of drug is slow. The most important feature of the mathematical relationship between the liquid concentration verses time is its ability to predict change in the performance of the drug by manipulating the parameters of the equation. These parameters include the initial concentration of the drug, the radius of the drug and diffusivity of the drug in the solid to name a few. Therefore, a substantial number of experiments can be eliminated when the optimal performance of a drug is sought after.