INFLUENCE OF CURING CONDITIONS ON THE DRUG-RELEASE RATE FROM EUDRAGITNE30D FILM-COATED SUSTAINED-RELEASE THEOPHYLLINE PELLETS

The purpose of this study was to determine the storage conditions (tim e, temperature and relative humidity,) required to obtain totally cure d films without any further changes in the drug release rates in the c ase of Eudragit NE30D coated sustained-release pellets. Furthermore, t he stability of films cui ed at high temperatures was evaluated by sto ring the coated pellets afterwards in ''normal'' conditions for long p eriods of time. All the results clearly indicate a decrease in drug re lease rates from coated pellets during the curing step. The curing rat es of coated pellets are higher when storage temperature and relative humidity increase. Moreover; when the coated pellets were exposed to e xtreme storage conditions, a further evolution in the drug release rat es was observed afterwards during their storage in ''normal'' conditio ns. Although it is necessary to perform curing to complete the film fo rmation from polymeric aqueous dispersions, attention must be paid to undesirable alterations of film and/or core properties, which are like ly to occur when extreme storage conditions are adopted.