Flow Studies on Directly Compressible Tablet Vehicles

Abstract

A number of methods of estimating ‘flowability’ of some direct compression vehicles have been evaluated as to their usefulness in predicting weight variation on tabletting. There was little or no inter-relationship between angle of repose, compressibility on tamping and flow rate values. In addition there was no correlation between any of these three values and tablet weight variation. In contrast cohesiveness and the reciprocal of the flow factor as determined from shear cell studies exhibited a fair correlation with weight variation of tablets produced on both a single punch and a rotary machine. It is suggested that the reciprocal of the flow factor is a direct measure of the tendency of the powder to arch or bridge during tabletting.