Abstract
Variation of the degree of crystallinity, lattice-disorder and crystallite size of pharmaceuticals with compression were investigated by X-ray powder diffraction method. The degree of crystallinity and lattice-disorder parameter were determined by Ruland's method. Crystallite size was calsulated by Scherrer's equation after correction for the instrumental broadening of the diffragtion line. Crystalline powders of aspirin and nicotinic acid were used as samples.The degree of crystallinity, lattice-disorder and crystallite size of pharmaceuticals varied with compression. In aspirin, the degree of crystallinity and crystallite size calculated from the profile of 100 reflection decreased and lattice-disorder increased with compression. The degree of crystallinity and crystallite size remarkably decreased immediately after compression and then recovered gradually with stress relaxation. In nicotinic acid powder, however, although the degree of crystallinity decreased and lattice-disorder increased with compression, these features did not recover with stress relaxation.
