Investigation of drug release from PEO tablet matrices in the presence of vitamin E as antioxidant.

The objective of this study wasto investigate the influence of drug type on the release of drug from PEO matrix tablets accompanied with the impact of vitamin E succinate as antioxidant.The resulted showed that the presence of vitamin E promoted a stable release rate of soluble drug propranolol HClfrom aged PEO matrix tablets, which was similar to fresh sample, regardless of molecular weight (MW) of PEO. However, the influence of the presence of vitamin E on the release rate of partially soluble drug, theophylline, was dependent on the MW of PEO; i.e., fast and unstable drug release was obtained in the case of low MW PEO 750 whereas stable drug release was obtained in the case of high MW PEO 303. The release of low water-soluble drug zonisamidewas stable regardless of both the presence of vitamin E and the MW of PEO. The presence of vitamin E slightly slowed the release ofzonisamide from aged PEO 303 matrices but not PEO 750 matrices. Therefore, in order to achieve a suitable controlled release profile from PEO matrices, not only the presence of vitamin E but also the solubility of drug and the MW of polyox should be considered