(503f) Development of a Model for Anisotropic Crystal Growth From Solutions

A model for anisotropic growth was developed. It is based on an isotropic growth model recently developed for crystal growth from solutions containing multiple conformers. The model presented herein implies that growth rates are constrained in one spatial dimension, thus only two linear growth dimensions, namely length and width, are considered. Crystal growth is assumed to occur via step propagation. The model takes into consideration step advance velocity dependence upon supersaturation and solvent/crystal interaction. An approach which uses two solute integration coefficients is introduced that describes crystal growth kinetics in each growth dimension. These coefficients are functions of the linear growth of the faces and are inclusive of solvent/crystal facet interactions. A parameter estimation algorithm to determine these coefficients is described. The algorithm requires experimental data of concentration variation during crystallization and final aspect ratio. The model’s predictions of temporal variation of supersaturation and final crystal elongation factor were in agreement with experimental data for a Bristol-Myers Squibb proprietary compound. Finally, model simulations allow for the estimation of integration coefficients for any given aspect ratio.