Crystallisation of lactose monohydrate from DMSO solutions: Influence of lactose

Abstract

In this study, the dimethyl sulfoxide (DMSO)-lactose system has been used to study the effect of lactose on the morphology of lactose monohydrate crystals. DMSO was used as the solvent as it greatly reduces the rate of mutarotation of lactose to lactose. It is shown that as the content of the solution increases, the crystal shape starts increasing in the a and b directions, whereas the major growth occurs in the c direction at low levels of lactose.The morphology of the lactose monohydrate crystal calculated by molecular modelling isin good agreement with that of the crystals grown in the presence of low lactose concentrations. Atomic force microscopy has revealed growth spirals and unit cell high steps on the (020) face of crystals grown in the presence of low anomer concentration.