In vitro controlled release of sodium ferulate from Compritol 888 ATO-based matrix tablets.

A controlled release matrix formulation for freely water-soluble drug of sodium ferulate (SF) was designed and developed to achieve a 24h release profile. Using Compritol 888 ATO as an inert matrix-forming agent to control the release of SF, formulation granules containing the physical mixtures or solid dispersions were investigated. The matrix tablets for these formulations were prepared by direct compression and their in vitro release tests were carried out. The solid dispersion based tablets were found to be more effective than those compressed from physical mixtures in retarding the release of SF. Drug release from the matrix tablets containing physical mixtures nearly completed within 12h, while that from the solid dispersion formulations lasted for over 24h. Images of the tablet surface and cross-section were characterized by scanning electron microscopy to show the formed pores and channels in the matrices. These might provide the release pathway for the inner embedded drugs. Drug released fast from the matrix tablets with the release-enhancer of lactose. The addition of surfactants was also found to increase the release rate of SF effectively. Moreover, the co-mixing of polyethylene glycol 6000 (PEG 6000) in the waxy matrices played a meaningful role in controlling the drug release for 24h. The drug release from the novel formulation might be attributed to the diffusion-controlled mechanism.