DEVELOPMENT AND EVALUATION OF BILAYER FLOATING DOSAGE FORM OF CARBIDOPA AND LEVODOPA FOR TREATMENT OF PARKINSON’S DISEASE

The combination of Levodopa and Carbidopa is widely prescribed for Parkinson’s disease. Levodopa easily crosses the blood-brain barrier and presumably converted to dopamine in the brain. Carbidopa inhibits decarboxylation of peripheral Levodopa but not of Levodopa within the central nervous system as it does not cross the blood-brain barrier. The purpose of present work was to develop bilayer floating dosage form of Carbidopa and Levodopa to improve the delivery of the drug at optimal absorption site and to reduce the frequency of administration with improved patient compliance. Bilayer floating tablet were prepared by using Kollidon SR and hydroxypropyl methylcellulose (HPMC K15M) as matrixing agents and sodium bicarbonate as gas generating agent. The IR spectral studies and DSC thermogram showed no interaction between drug and other additives. Experimental design was used for optimizing the ratio of Kollidon SR: HPMC K15 (X1) and concentration of binder (X2). The optimized formulation (batch F3) showed zero order drug release with Non-Fickian or anomalous diffusion. The optimized formulation showed similarity in dissolution with theoretical profile (f2 value for Levodopa is 85.01 and for Carbidopa is 81.94). The floating lag time was 42 second and the tablet remained floatable for more than 24 h. The stability study of optimized formulation for 1 month showed no appreciable change in drug content, in vitro drug release and floating lag time.