(601b) An Observed Correlation Between Flow and Electrical Properties of Pharmaceutical Blends
AIChE Annual Meeting
2008 Annual Meeting
Food, Pharmaceutical & Bioengineering Division
Innovations in Pharmaceutical Process Development
Thursday, November 20, 2008 - 8:50am to 9:10am
We study the relation between flow and conductivity of multiple formulations of pharmaceutical powder blends. Ten formulations were tested, consisting of two excipient sets, two active preparations, and a variety of food-grade additives including Magnesium Stearate (MgSt), and ionic and conductive materials such as ascorbic acid, talc, sodium carbonate, colloidal silica and TiO2. Impedance, flow index and dilation were independently measured for all of the blends, and a strong correlation was found between every pair of these three properties. The relation between flow and dilation has been observed before; we find for the first time that there is a nearly linear relationship between flow index or dilation and impedance. This indicates that cohesive powder behavior depends on powder electrical properties, raising the question of whether additives such as MgSt affect friction and conductivity per se or whether these effects may be consequent to changes in electrical properties.