Influence of an Enteric Polymer on Drug Release Rates of Theophylline from Pellets Coated with Eudragit® RS 30D

The purpose of this research study was to investigate the influence of an enteric polymer on the drug release properties of theophylline pellets coated with Eudragit® RS 30D. Theophylline pellets were coated with aqueous colloidal dispersions of Eudragit® RS 30D containing various amounts of Eudragit® L 100-55. The effect of storage conditions on the release of drug from coated pellets was determined as a function of the pH of the dissolution medium. The results from the dissolution study showed significant changes in the dissolution rate of theophylline from pellets coated with Eudragit® RS 30D when cured at 40°C for 4 days. No change in the drug release rate was observed when Eudragit® L100-55 was present in the Eudragit® RS 30D dispersion. Increasing the ratio of Eudragit® L100-55 to Eudragit® RS 30D resulted in faster drug release rates from the coated pellets. An increase in the pH of the dissolution medium was found to enhance drug release from the pellets coated with Eudragit® RS 30D containing Eudragit® L 100-55. Theophylline pellets when coated with Eudragit® RS 30D containing the enteric polymer Eudragit® L100-55 demonstrated no aging effects when stored at elevated temperatures. The overcoating of the pellets with Eudragit® RD 100 did not affect the drug release profiles and prevented the particles from agglomerating during curing and storage.