A multiparticulate drug-delivery system based on pellets incorporated into congealable polyethylene glycol carrier materials.

As a novel alternative to the incorporation into hard gelatin capsules or tablets, extended-release (Aquacoat- or Eudragit RS-coated) or enteric (Eudragit L-coated) pellets were embedded into congealed tablet-shaped PEG-plugs of different molecular weights, which rapidly released the pellets upon contact with aqueous fluids. The lower-molecular-weight PEGs (600 and 1000) were not suitable carrier materials: they dissolved the coatings or significantly increased their permeability. The release characteristics of the original pellets were maintained after embedding the pellets into the higher-molecular-weight PEGs 4000 or 10000. The shelf-life stability was a function of storage temperature and coating material. Stored at 40 degrees C, Aquacoat-coated pellets embedded in PEG 4000 exhibited a decreased drug release because of curing effects, while storage at 20 degrees C or below resulted in stable release profiles over a 3 month period. Eudragit RS-coated pellets, stored at room temperature or above, showed an increased release, and the carrier material possibly migrated into the film, thus increasing its permeability. At 4 degrees C, the release was stable over a 6 month period.