During production of microparticles by the polymer incompatibility method a polymer solution is demixed. Therefore, investigations into solubility are often carried out when the suitability of a polymer is examined. Solubility parameters can be used to quantify the solubility. For polylactide and polyglycolide as commonly employed copolymers for microparticles the solubility parameters have rarely been documented. This study aimed to determine solubility parameters and partial solubility parameters for different proportions of lactide to glycolide for poly(D,L-lactide-co-glycolide) (PLGA). The employed methods were compared and solubility maps established. Finally the accuracy of the results was discussed for different polymer batches which were used for production of microparticles. Although the turbidity titration method was found to be the most precise, it was not possible to sufficiently explain the differences between three polymer batches during microparticle production.

copyright 2004 Elsevier B.V.