PREPARATION OF A CONTROLLED-RELEASE DRUG-DELIVERY SYSTEM OF INDOMETHACIN

The preparation of a sustained release dosage form for indomethacin was studied. Pellets (I) containing indomethacin were prepared by spraying a slurry of indomethacin, Eudragit(R) S-100, dibutyl sebacate and alcohol onto non-pareil seeds via Wurster column processing. The resultant pellets were further coated with various combinations of Eudragit(R) RS (poorly water permeable) and Eudragit(R) RL polymers (readily water permeable) also using the Wurster column. In-vitro dissolution tests were conducted in a USP dissolution apparatus containing 900 mi of phosphate buffer at either pH 6.5 or 7.2. The in-vitro release studies of pellets (I) at pH 6.5 phosphate buffer exhibited a root T dependence indicating a diffusion controlled process from a matrix formulation. At ph 7.2 phosphate buffer, pellets coated with Eudragit(R) RS showed the most retardation in the release rate of drug. As expected, the total amount of drug released from the coated pellets increased as the concentration of Eudragit(R) RL increased in the barrier coating. Pellets coated with Eudragit(R) RL alone showed the fastest release rate of drug.