EVALUATION OF 4 MICROCRYSTALLINE CELLULOSE GRADES FOR PREPARING SPHERICAL BEADS IN A CENTRIFUGAL GRANULATING PROCESS

In the present study, four commercial microcrystalline cellulose grade s (Emcocel SM15, 50M, 90M and HD90) were evaluated for preparing spher ical beads (substrates for drug layering) in a centrifugal granulating process. The mechanisms of microcrystalline cellulose core formation and growth were found to be similar to the spheronizing process of pel lets. The wetting phase (nucleation region) was followed by combinatio n of coalescence between the previously formed nuclei and the layering of the smaller fine powder over the nuclei. Finally, layering and abr asion transfer were the predominant mechanisms. All formulations (I to IV) studied exhibited relatively spherical, smooth, well-flowing and mechanically strong final bends. The size and the density of the cores followed the same order as the filler used The size distribution of t he beads was narrow and satisfactory with the exception of formulation IV. The results suggest that different microcrystalline cellulose gra des could be used as starting materials for preparing substrates for d rug layering in a centrifugal granulating process.