EFFECT OF GEOMETRY ON THE EROSION CHARACTERISTICS OF POLYANHYDRIDE MATRICES

The aim of this study was to investigate the effect of device geometry on the erosion characteristics of poly[1,3-bis(p-carboxyphenoxy) prop ane:sebacic acid], p(CPP:SA), matrices in phosphate buffer to obtain a n insight into the mechanism of polyanhydride erosion. Matrices with d ifferent dimensions were prepared using a melt moulding technique and erosion was followed by determining changes in polymer molecular weigh t, water absorption, mass loss and release of monomers with time of im mersion in phosphate buffer pH 7.4 at 37 degrees C. In all matrices th e erosion process was characterised by an initial lag phase during whi ch there was a rapid decrease of polymer molecular weight but no signi ficant water absorption, mass loss or release of monomers. The rates o f absorption of water and loss of mass after the lag period showed cha racteristics of both surface and bulk eroding systems. (C) 1998 Elsevi er Science B.V.