title: Studies of diffusional release of a dispersed solute from polymeric matrixes by finite element method.
abstract: This paper presents systematic analyses by the finite element method of release kinetics of a dispersed solute from various matrixes (i.e. , slab, sphere, cylinder, and convex tablet), with or without boundary-layer resistance, into a finite or an infinite external volume. In the case of sink conditions, the numerical results agree well with the existing analytical solutions. For the problems of solute release into a finite external volume, where the analytical solutions are not available, this work has provided numerical solutions of the differential equations describing the release kinetics, moving boundaries, and concentration profiles. This work has also revealed the dependence of release kinetics on the initial solute loading, the external volume, and the boundary-layer thickness. The method presented here can describe the entire process of diffusional release before and after the dispersed solute has been dissolved without the pseudo steady-state assumption and it is applicable to both small and large ratio of initial solute loading to the solute solubility in the matrix.
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada M5S 2S2. xywu@phm.utoronto.ca
authors.forename: X Y
authors.initials: XY
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000465:Algorithms; D004058:Diffusion; D020342:Finite Element Analysis; D007700:Kinetics; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011108:Polymers; D013607:Tablets
chemical_list: D004364:Pharmaceutical Preparations; D011108:Polymers; D013607:Tablets