Application of powder failure testing equipment in assessing effect on glidants on flowability of cohesive pharmaceutical powders.

Powder failure testing equipment was used successfully to study the effect of glidants on the flowability of two cohesive pharmaceutical powders, lactose and calcium hydrogen phosphate, using the flow factor as the flowability parameter. Fine silica, magnesium stearate, and purified talc were investigated as glidants; for each host powder-glidant mixture, an optimum concentration of glidant was observed beyond which no further increase in flowability occurred. The order of efficiency of glidants for both host powders was fine silica greater than magnesium stearate greater than purified talc. The mode of action of the three glidants is discussed.