title: Calculation of the dimensions of drug-polymer devices based on diffusion parameters.
abstract: The release kinetics of a polymeric-controlled release device are determined by its geometry and dimensions. A method to calculate the required size and shape of diffusion-controlled dosage forms to achieve a particular release profile is presented. The diffusion parameters are determined for various drugs (theophylline, diltiazem hydrochloride and caffeine) with thin ethyl cellulose (EC) films, containing different plasticizers [dibutyl sebacate (DBS) and acetyl tributyl citrate (ATBC)]. Computer simulations are then used to predict the drug release kinetics from various dosage forms (e.g. microparticles and cylinders). The practical benefit of these simulations is to optimize the geometry and dimensions of a controlled release device without the need of experimental studies. To verify the theoretical predictions, the release kinetics of theophylline from EC/ATBC microparticles of different size have also been determined experimentally. Good agreement is found between theory and experiment, proving the validity of the presented method.
authors.affiliation: College of Pharmacy, Freie Universität Berlin, Kelchstrasse 31, 12169 Berlin, Germany and Faculty of Sciences, University of Saint-Etienne, France.
authors.forename: J
authors.initials: J
authors.lastname: Siepmann
authors.forename: A
authors.initials: A
authors.lastname: Ainaoui
authors.forename: J M
authors.initials: JM
authors.lastname: Vergnaud
authors.forename: R
authors.initials: R
authors.lastname: Bodmeier
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003198:Computer Simulation; D003692:Delayed-Action Preparations; D004058:Diffusion; D007700:Kinetics; D008432:Mathematical Computing; D010316:Particle Size; D010599:Pharmacokinetics; D011108:Polymers / Q000737:chemistry* / Q000493:pharmacokinetics
chemical_list: D003692:Delayed-Action Preparations; D011108:Polymers