POLYMORPHISM IN A NOVEL ANTIVIRAL AGENT - LAMIVUDINE

Two modifications of Lamivudine have been studied. One has a highly sy mmetrical crystal lattice and the other, unusually, an asymmetric unit containing five non-equivalent molecules (with some disorder). The la tter contains one molecule of water for every five of Lamivudine. Soli d-state NMR spectra reflect these dramatic differences and the techniq ue has been used to predict the extent of the asymmetry in the latter form. X-Ray diffraction studies confirm the differences in symmetry be tween the two polymorphs, which have also been characterised by LR spe ctroscopy and differential scanning calorimetry.