PREFERRED ORIENTATION OF CRYSTALLITES IN TABLETS .4. FEATURES OF THE PREFERRED ORIENTATION PLANE

Features of the preferred orientation plane of some organic crystals w ere studied from a quantum chemical point of view. The interaction ene rgies in those crystal planes in which cleavage is possible were calcu lated by using the interaction energies between two molecules. The int ermolecular interaction energies were calculated by the CNDO/2 (comple te neglect of differential overlap) method. The preferred orientation planes, which have a tendency to orient themselves parallel to the upp er surface of a tablet during compression, showed only small interacti on energy. Thus, the preferred orientation of crystallites in a tablet was considered to occur by cleavage along that crystal plane which ha d small interaction energy during compression.