RELEASE OF CARBAMAZEPINE FROM SOLID DISPERSIONS WITH POLYVINYLPYRROLIDONE VINYLACETATE COPOLYMER (PVP/VA)/

Solid dispersions of carbamazepine with polyvinylpyrrolidone/vinylacet ate copolymer at different loading ratios were prepared to study the i nfluence of this copolymer on the solubility and dissolution rate of t he drug. The greatest increase in the dissolution rate of carbamazepin e was obtained from solid dispersion at the 1/4 (w/w) drug/polymer rat io. Furthermore, the influence of pH on dissolution was studied. The d ata indicate that the release profile of the drug is not modified by a change in pH. Several kinetic models have been applied in an attempt to describe the mechanism of drug dissolution. Physical characterizati on of the prepared systems was carried out by differential scanning ca lorimetry (DSC), X-ray diffractometry and wettability studies.