Abstract

The ability to convert potent herbal medicines into robust tablet will require a good understanding of certain critical factors such as effect of binder concentration on granule particles and tablets properties. In this study, granules of AM-1, a prototype herbal extract has been produced by the wet granulation process of massing and screening using different concentrations of maize starch gel as binder. The effect of the binder concentrations and granule particles’ size on the granules’ flow and moisture uptake characteristics as well as, their effect on the friability and tensile strength of tablets produced with the granules were investigated. The AM-1 granules prepared with the different concentrations of maize starch gel as binder were of variable particulate dimensions. The particle size and size distribution of the granules showed a remarkable binder concentration sensitivity with a shift to larger particles with increasing binder concentrations. The flow of the granules as determined by evaluating their angle of repose and Carr compressibility indices showed enhanced flow relative to the unformulated AM-1. At simulated tropical humidity and temperature conditions, the AM-1 granules exhibited binder concentration sensitivity to moisture uptake. There was also a reduction in the moisture uptake ability of the granulated AM-1 relative to the ungranulated sample. The tensile strength and friability of the AM-1 tablets showed binder concentration and granule particle size sensitivity: the duo increased with increase in binder concentrations as swell as particle size.  This study has shown the effects of granulation as well as starch gel concentration on some critical formulation properties of an herbal extract AM-1, obtained by freeze drying the aqueous decoction of a powdered root material.

Key words: Herbal extract AM-1, starch gel, binder concentration, granule properties, tablet properties.