Bulk density is one of the important pharmaceutical characteristics of
pharmaceutical powders. Though not required by Pharmacopoeias, it is
often declared in the certificate of analysis of different pharmaceuti
cal raw materials. It directly influences the preparation of different
pharmaceutical forms: suspensions, capsules, tablets, etc. The effect
of the size and shape of crystals on the bulk density of pharmaceutic
al powders was studied. As the model substance, 5-aminosalicylic acid
was used. The crystals of 5-aminosalicylic acid were obtained by preci
pitation of the crude product dissolved in a dilute acid, by a dilute
base to the equivalence point. The different parameters influence the
crystals size and shape. According to the precipitation conditions, tw
o types of product were obtained: regular bulk density (loose) 0.10-0.
35 g/ml (N-type) and high bulk density 0.35-0.60 g/ml (C-type).