Evaluation of Ceolus™ microcrystalline cellulose grades for the direct compression of enteric-coated pellets.

The preparation of multiparticulate tablets by direct compression of functionally coated pellets is technologically challenging. The objective was to investigate the influence of different grades of microcrystalline cellulose (Ceolus™ UF-711, PH-102, PH-200 and KG-802) as fillers on the properties of blends and tablets containing enteric pellets. Celphere™ spheres were drug-layered and then functionally coated with Eudragit(®) L 30 D-55/FS 30D dispersion. Tablets loaded with 50% pellets were prepared using pure or binary blends of microcrystalline cellulose fillers. The influence of the filler on the blend flow, segregation tendency, tablet hardness and enteric release properties were studied using a mixture design, and the optimum filler composition was determined. Rapidly disintegrating tablets, which yielded a drug release of less than 10% after 2 hours in acidic medium, could be successfully prepared. The blend composition had a significant effect on the flowability, but less on the tablet hardness which was influenced by the selection of lubricant. Blends containing celluloses with low bulk densities exhibited a reduced tendency to segregate. Pellet distribution uniformity was further improved when using Ceolus™ UF-711 blended with a high-density grade. As a conclusion, multiparticulate tablets containing enteric pellets with preserved delayed-release properties were successfully prepared using Ceolus™ microcrystalline celluloses as tableting excipients. The optimized filler blend for the direct compression of 50% enteric pellets into tablets contained Ceolus™ UF-711 as main component in combination with Ceolus™ PH-200.