Mathematical modelling of drug release from multi-layer capsules

TL;DR

This paper develops an analytical mathematical model to describe drug release from multi-layer capsules, accounting for both ideal and resistive interlayer mass transfer, providing detailed concentration profiles.

Contribution

It introduces a coupled PDE model for multi-layer capsules and solves it analytically, including cases with finite interlayer resistance, advancing understanding of drug release mechanisms.

Findings

Analytical solutions for drug concentration profiles in multi-layer capsules

Inclusion of finite mass transfer resistance in the model

Numerical Fourier series characterization of drug release

Abstract

We propose a mathematical model for computing drug release from multi-layer capsules. The diffusion problem in such heterogeneous layer-by-layer composite medium is described by a system of coupled partial differential equations, which we solve analytically using separation of variables. In addition to the conventional interlayer continuous mass transfer boundary conditions, we consider also the case of finite mass transfer resistance, which corresponds to the case of a coated capsule. The drug concentration in the core and through all layers, as well as in the external release medium, is then given in terms of a Fourier series that we compute numerically to characterize the drug release mechanism.