https://doi.org/10.1140/epjst/e2016-02669-8
Regular Article
Dynamics of the fraction of drug particles near the release boundary
Justifying a stretched exponential kinetics in Fickian drug release
1 University of Patras, Materials Science Dept., Rio 26504, Greece
2 Crete Center for Quantum Complexity and Nanotechnology (CCQCN), Physics Dept., University of Crete, 71003 Heraklion, Greece
Received: 28 March 2016
Revised: 26 July 2016
Published online: 30 September 2016
We consider a drug release formulation and investigate the evolution of the fraction of drug molecules that are sufficiently close to the release boundary, in order to check the validity of the assumption underlying the theoretical derivation of a stretched exponential (Weibull) release kinetics. Diffusion-controlled drug release from spheres and slabs is considered. Both analytical results and Monte Carlo simulations are used to calculate the evolution of diffusive drug particles. We find that the fraction of drug molecules near to an exit, as a function of time, follows an inverse power-law in a substantial part of the release problem (from around 1–5% up to at least 80% of the release), justifying an approximate description of the release kinetics through a stretched exponential function.
© EDP Sciences, Springer-Verlag, 2016
