The effects of molecular weight and porosity on the degradation and drug release from polyglycolide

This paper explores the influence of initial molecular weight and porosity on the release of the drug, theophylline, from polyglycolide (PGA). PGA was made by a variety of processes to vary the molecular weight and was blended with NaCl with different crystal sizes and in different proportions to vary the pore size and volume. Overall, results showed that decreasing the molecular weight and increasing the pore size and volume increased the rate of drug release, The exact variation of these trends agreed well with the previously established four-stage degradation mechanism for PGA, but was more complex than a simple linear behaviour. Because both the molecular weight and the porosity of PGA have a substantial influence on the polymer degradation, and can be varied in a controlled manner, these parameters can play an important role in developing PGA as a controlled drug delivery material with tailored drug release. (C) 2004 Elsevier B.V. All rights reserved.