Polyglycolide: degradation and drug release. Part II: drug release.

This paper considers drug release from a polyglycolide (PGA) matrix and is divided into two sections. The first investigates the effects on the degradation of the polymer of incorporating a model drug, theophylline, into the polymer. Small and wide angle X-ray scattering, and mass loss and water uptake measurements indicate that the presence of this drug does not affect the time scale of the degradation process. However, the dissolved theophylline molecules affect the extent to which the polymer crystallizes during degradation. In the second section, theophylline release profiles, obtained using UV-spectrophotometry, show that the erosion of the polymer controls the release of the drug. The drug release results add further evidence to support the four stage degradation process which was described in Part I.