DEVELOPMENT AND IN VIVO EVALUATION OF TOLCAPONE CONTROLLED RELEASE TRILAYER MATRIX TABLETS BY GEOMATRIX TECHNOLOGY Original Article

Objective: The present study was aimed to develop once-daily controlled release tri-layer matrix tablets of tolcapone, to achieve zero-order drug release for sustained plasma concentration by Geomatrix. Methods: Tolcapone trilayer matrix tablets were prepared by direct compression method and consisted of active middle layer with different grades of hydroxypropyl methylcellulose (HPMC), ethyl cellulose and sodium CMC. Barrier layers were prepared with Eudragit L100-55, guar gum, sodium CMC and DCP. Results: Based on the evaluation parameters, drug dissolution profile and release order kinetics, formulation HF16 was found to be optimized formulation. The developed drug delivery system provided prolonged drug release rates over a period of 24 h. The release profile of the optimized formulation (HF16) was described by the zero-order and best fitted to Higuchi model. FT-IR and DSC studies confirmed that there was no chemical interaction between drug and excipients used in the formulation. The Tmax of the optimized formulation HF16 was significantly different (p<0.05) from that of the marketed product. Low Tmax value for the marketed product (2.02±0.02 h) indicates rapid absorption while the higher Tmax of the optimized formulation (6.00±0.04 h) suggests slower absorption. This delayed absorption of test preparation is most likely due to the sustained release of the drug. Conclusion: The results indicate that the approach used could lead to a successful development of a controlled release formulation of the drug. In vivo studies revealed that the optimized formulation HF16 was shown significant plasma concentration with the controlled release and maintained for 24 h with patient compliance by reducing the dosage frequency when compared with Marketed product in the efficient management of Parkinson’s disease.