Study of Crystalline Drugs by Means of a Polarizing Microscope. XVI. Preparation of Particle Size and Specific Surface Area Distribution Curves of Crystalline Drugs Using the Similarity of Their Crystal Habits
Atsushi Watanabe, N Ohnuma · YAKUGAKU ZASSHI · 1996
Polarizing photomicroscopy using the immersion method were bound to be useful to clarify the relationship between crystal habits and characteristics such as key refractive indices or a birefringence. It was found that there was similarity in the crystal habits among crystals in the same lot which have the same key refractive indices especially when they have similar habit coefficients each other. Using the average habit coefficients as well as the obtained parameter b-values from traces of a proper interference photo under crossed polars, the distributions of particle sizes and specific surface areas are easily calculated using a personal computer. The results of the several products of phenytoin, dygitoxin and lanatoside C crystals were graphically shown and discussed, compared with the results obtained by the sieving method.