YOUNG MODULUS OF POWDERS USED AS PHARMACEUTICAL EXCIPIENTS

The Young's modulus (E) of 15 representative tableting excipient powders has been measured for compressed rectangular beam specimens over a range of porosities using a four-point beam bending technique. Calculated values of Young's modulus at zero porosity (E0) provide a means of categorising the mechanical characteristics in terms of elasticity and rigidity (stiffness) and brittleness on a quantitative scale. The order of increasing stiffness for the studied materials was starch < microcrystalline celluloses < sugars < inorganic fillers (calcium carbonate, calcium phosphate), with values of E0 ranging from 3.71 to 88.28 GPa. Differences in E0 for alternative sources of similar materials are discussed in terms of manufacturing pretreatment and crystallo-graphic structure. © 1990.