Roll compaction/dry granulation: Suitability of different binders.

As dry granulation as a continuous process becomes steadily more important, the interest of different materials and their processing is growing. Binders are of high importance as they have to compensate granule hardening, reduce the fines, and ensure adequate tablet tensile strengths. A simple formulation was used for roll compaction/dry granulation with subsequent tableting to produce granules and tablets, containing paracetamol (70% w/w), a filler and a binder (10%). With this formulation other influences were negligible and the influence of the binder was almost isolated. Eight different binders were compared with special attention to raw material properties. Six of them were cellulose based and two of them were based on povidone. Granule size distributions were typically bimodal. With the same method of preparation, large differences between the formulations occurred. The median particle size of granules differed from 200 μm, up to barely 700 μm. The larger the resulted particles, the higher was the tensile strength after tableting. Tablets with fine grades of HPC and copovidone achieved highest tensile strength exceeding 2.5 MPa at a compaction pressure of 350 MPa. Formulations with other binders were inferior, but mostly adequate. MCC performed insufficient and led to capping.