DISSOLUTION RATES OF DIFFERENT DRUGS FROM SOLID DISPERSIONS WITH EUDRAGIT RS

Coprecipitates of different drugs with Eudragit RS were prepared by dr ying of a mixed solution of polymer and drug to investigate the effect of this polymer on the dissolution behaviour of the drugs. The physic ochemical properties of the solid dispersions were determined by X-ray diffractometry and differential scanning calorimetry (DSC). A delayed release was found by increasing the amount of the polymer in the soli d dispersions. Dissolution tests of the coprecipitates were performed at two different pH values and drug release was slower at pH 7.4 than pH 5. In order to establish a correlation between the physical propert ies of the drugs and their release profiles a statistical analysis was carried out by Partial Least Square Method (PLS). Molecular weight an d molar refractivity of the drugs were the most important variables in fluencing their release from coprecipitates.