Evaluation of a novel cellulose powder as a filler-binder for direct compression of tablets.

A novel form of cellulose powder was evaluated as a filler-binder in tablets. The particle, powder, flow and binding properties of this experimental cellulose material were compared with those of two commercial microcrystalline celluloses, Avicel PH 101 and Emcocel. The effect of various storage conditions on the physical stability of tablets compressed from celluloses was also evaluated. The particle size and shape of experimental cellulose powder differed markedly from those of microcrystalline celluloses. Experimental cellulose contained mainly large and roughly spherical agglomerates of particles, among which were few smaller regularly shaped particles. Because of spherical particle shape, the experimental cellulose powder flowed better than microcrystalline celluloses, which consisted of much more irregularly shaped particles. Experimental cellulose formed stronger tablets than microcrystalline celluloses. It also acted more effectively than microcrystalline celluloses as a binding material in tablets containing poorly compressible ascorbic acid and acetaminophenone. This may be due to the extensive surface area of the particles of experimental cellulose powder. The specific surface area of this material was over 50 times as great as that of microcrystalline celluloses. This indicates an extremely porous structure of cellulose agglomerates. Tablets containing experimental cellulose powder were able to resist a permanent loss in tablet strength at different storage conditions better than tablets containing microcrystalline celluloses. According to the results of this study an experimental agglomerated form of cellulose powder is a very advantageous material as a filler-binder for direct compression of tablets.