Understanding Crystal Cleavability and Physical Properties of Crystal Surfaces Using in Silico Simulation.
In the drug formulation process, compound dissolution rate and wettability may be improved by grinding. However, there is no method to understand the effects of the wettability of the crystal facets of the ground product. Here, acetylsalicylic acid (ASA) was used to evaluate the changes in crystal morphology and dissolution rate by jet milling using powder X-ray diffraction and in silico simulation. Several cleavage facets were observed in cube crystals, and the (0 0 2) facet was observed in plate crystals. Furthermore, the dissolution rate of the ground samples per unit area decreased with the cleavage of the (1 0 0) and (0 0 2) facets. The polar surface energy of the ground sample decreased with increasing grinding pressure. The simulation results showed that the absolute attachment energy of the (1 0 0) and (0 0 2) facets was lower than that of the other crystal facets. Moreover, atoms with low polarity were present on the crystal surface of (0 0 2). The wettability and dissolution rate of the (0 0 2) facet were worse than those of the (1 0 0) facet. It was suggested that the dissolution rate of the ground sample was affected by the wettability of the crystal facet caused by the cleavage. The cleavability and wettability may be understood by simulation.
['Hatanaka|Toshiaki|T|', 'Yoshihashi|Yasuo|Y|', 'Terada|Katsuhide|K|', 'Yonemochi|Etsuo|E|']
D001241:Aspirin D003198:Computer Simulation D003460:Crystallization D004339:Drug Compounding D010316:Particle Size D011208:Powders D011312:Pressure D012995:Solubility D013499:Surface Properties D017155:Wettability D014961:X-Ray Diffraction
in silico simulation wettability crystal facet acetylsalicylic acid cleavage