Morphological and growth rate distributions of small self-nucleated paracetamol crystals grown from pure aqueous solutions

The growth rate dispersion of small paracetamol crystals nucleated and grow n from pure solution was measured over the range of supersaturation, 0% < s < 20%, in the three different crystallographic directions: [0 0 1], [1 1 0 ] and [0 1 0]. The results were fitted to three parameter log-normal and ga mma distribution functions. The average growth rates obtained from these di stributions were used to predict the morphological behaviour of an assembly of small paracetamol crystals as a function of supersaturation. It was sho wn that a columnar shape (dominant {1 1 0}) was formed in regions of low su persaturation while a plate-like form (dominant {0 0 1}) prevailed at high supersaturations. Using optical microscopy and X-ray topography, the potent ial causes for both the growth rate distribution and morphological change w ere investigated. (C) 1999 Elsevier Science B.V. All rights reserved.