Abstract

Absorbable polyesters implants, such as poly(L-lactic acid), have been used in various fields of medicine. The understanding of morphologic characteristics of the material and the interaction material-tissue is basic for the success of the implant. In this research, the degradation in vitro, in phosphate-buffered solution, of dense and porous membranes of PLLA prepared by casting-solvent, was evaluated. Porous membranes were prepared by adding sodium citrate (range: less than 45 micrometers, 180-250 micrometers and 250-350 micrometers) into the polymeric solution. Samples were immersed in a híith of buffer phosphate 0.13 mol/L (pH=7.4), al temperature of 37 'C. After the samples were submitted for 30. 60 and 50 days to the degradation process, they were observed by Scanning Electron Microscopy (SEM). Dense membranes presented superior degradation in relation to the porous ones due to the process of autocatalysis of PLLA thal generates the concentration of acids inside the material.