Degrees of crystallinity and polymerization of modified cellulose powders for direct tableting

The degrees of crystallinity and of polymerization of 21 celluloses used in direct tableting were determined, using X-ray diffraction and viscosimetry respectively. The crystallinity of the microcrystalline celluloses varied widely from one product to another. Average degrees of polymerization were less than the usually accepted value of the “level-off degree of polymerization”. Degrees of crystallinity of powdered celluloses were generally lower than those of microcrystalline celluloses, although some were as high as those of certain hydrolyzed samples. Degrees of polymerization of powdered celluloses did not differ as much as those of microcrystalline celluloses. The observed ranges for both parameters were wider than previously reported; the differences could be explained by structural considerations.