Release of ibuprofen from poly(ε-caprolactone-co-D,L-lactide) and simulation of the release

A study was made of the effects of the initial ibuprofen load and of the specimen shape on the release of ibuprofen from poly(epsilon-caprolactone-co-D,L-lactide). The mol ratio of the comonomers in the copolymer was 96/4 (caprolactone to lactide) and the experiments were conducted at 37degreesC in vitro. The results showed that release of ibuprofen is fast and that the rate and profile of the release vary with both the initial load of ibuprofen and the shape of the specimen. The rate of ibuprofen release increases with the initial load and with the surface area-to-volume ratio of the specimen, obeying Fickian diffusion. The experimental findings were compared with the results of a mathematical simulation model based on the finite-difference method. Diffusion parameters needed for the simulation were determined from a separately conducted set of experiments using various methods. For the most part, the results of the simulations and the experiments were in good agreement. (C) 2003 Wiley Periodicals, Inc.