Study of Ethyl Cellulose Based Sustained Release Microspheres of Naproxen Sodium

The present study was conducted to prepare sustained release microspheres of naproxen sodium using ethyl cellulose (Ethocel 20 cps) polymer. Three different plasticizers namely polyethyleneglycol 600 (PEG 600), polyethyleneglycol 6000 (PEG 6000) and triethyl citrate (TEC) were used at 10% (wt/wt) and 40% (wt/wt) level of the drug content. Prepared microspheres were characterized with respect to drug loading, microsphere particle size, microsphere surface morphology and release behavior. Surface morphology of the microspheres was examined in a scanning electron microscope. Drug release was observed in phosphate buffer solution of pH 6.8 for 8 hours. At 10% level of the plasticizers, percent release was 93.36%, 93.02% and 92.67% for PEG 600, PEG 6000 and TEC respectively after 8 hours. On the other hand, at 40% level, percent release was 81.12%, 70.06% and 51.12% for PEG 600, PEG 6000 and TEC respectively after the same duration. Release mechanisms followed case I or fickian model.