Dissolution and crystal growth in aqueous suspensions of cortisone acetate

Abstract

The change in particle size distribution of cortisone acetate in aqueous (saline) suspensions has been examined using the Coulter Counter. Rate of growth under standardized conditions was calculated as increase of diameter per unit time. Solubility of a water-unstable crystal form has been shown to be greater than that of the stable form. Discussion of the results reveals that crystal growth is mainly initiated by polymorphic transformation. Lattice energies, heats of wetting and solution of the different crystal forms are thought to be the rate controlling factors.