Effect of neutralization of poly(methacrylic acid-co-ethyl acrylate) on drug release from enteric-coated pellets upon accelerated storage

The effect of neutralization of poly(methacrylic acid-co-ethyl acrylate) or poly(MA-EA) 1:1 (Eudragit^® L 30 D-55) on drug release from enteric-coated pellets was studied upon accelerated storage. The dissolution rate of un-neutralized poly(MA-EA)-coated pellets decreased while the neutralized polymer-coated pellets maintained a constant drug release rate. Dynamic mechanical analysis showed that both un-neutralized and neutralized poly(MA-EA) films became rigid on aging. However, the un-neutralized films were affected more than those neutralized. Neutralization of poly(MA-EA) significantly changed the mechanical properties of coating films and improved the stability of poly(MA-EA) enteric-coated pellets upon accelerated storage at the studied conditions.