Development and characterization of eudragit RS 100 loaded microsponges and its colonic delivery using natural polysaccharides.

In the present work, paracetamol loaded eudragit based microsponges were prepared using quasi-emulsion solvent diffusion method. The compatibility of the drug with various formulation components was established. Process parameters were analyzed in order to optimize the formulation. Shape and surface morphology of the microsponges were examined using scanning electron microscopy. The formulations were subjected to in vitro release studies and the results were evaluated kinetically and statically. The in vitro release data showed a bi-phasic pattern with an initial burst effect. In the first hour drug release from microsponges was found to be between 17-30%. The cumulative percent release at the end of 8th hour was noted to be between 54-83%. The release kinetics showed that the data followed Higuchi model and the main mechanism of drug release was diffusion.The colon specific tablets were prepared by compressing the microsponges followed by coating with pectin:hydroxypropylmethylcellulose (HPMC) mixture. In vitro release studies exhibited that compression coated colon specific tablet formulations started releasing the drug at 6th hour corresponding to the arrival time at proximal colon. The study presents a new approach for colon specific drug delivery.