The influence of binder concentration on the bond formation of pharmaceutical granules

The formation of particle mucilage bonds with dicalcium phosphate dihydrate and starch mucilage binder reduces the B.E.T. nitrogen adsorption surface are from 196 to 0.96 m2 g-1. The maximum reduction (40%) of granule surface area at a binder concentration of 10% w/w corresponded to similar optima in friability, compressability and median granule size. Surface and pore-void structural analysis by mercury intrusion could not discriminate between pore-void sizes in the range 0.5-100 nm. Nitrogen adsorption measurements showed, however, that the microporous surface area decreased from 0.3 to 0.18 m2 g-1 as binder surface coverage increased over the concentration range 2 to 20% w/w starch mucilage.