Crystallisation of paracetamol (acetaminophen) in the presence of structurally related substances

Paracetamol was crystallised from aqueous solutions containing various concentrations of structurally related compounds. Crystal shape was characterised by image analysis and the additive concentration incorporated into the crystals determined by HPLC. The crystal structure of pure acetaminophen displays a hydrogen bonded network, from which is derived a mechanistic interpretation of the abilities of additive molecules to influence crystal growth. This structural approach was used to explain the observed additive uptake, the morphological changes, and the previously reported inhibition of nucleation. (C) 1998 Elsevier Science B.V. All rights reserved.