Influence of the granulating method on bulk properties and tablettability of a high dosage drug

Abstract Tocainide hydrochloride, a high dosage drug, was granulated by spraying in a fluid bed granulator or by wet massing in a planetary mixer. The influence of the granulation method and the amount of binder, 0–3.4% methylcellulose (MC), on granulate properties and tablet strength was investigated. Tablets were prepared by using an instrumented tablet machine. Fluid bed granulation with sufficient amounts of MC gave a granulate with a narrow particle size distribution and good flowability. The best flow properties were obtained by prolonged spraying with dilute binder solutions. Wet massing produced a denser granulate with poorer flow properties and was very little affected by the amount of MC. Fluid bed granulates gave considerably stronger tablets than traditional granulates. High MC-concentrations and long spraying time improved the bonding properties. The tablet strength correlated well with the work required for compression, indicating that improved bonding properties were mainly caused by changed deformation behaviour during compaction.