Modulation of the powder properties of lamotrigine by crystal forms.

Here at Gamlen we are highlighting some of the fascinating and ground-breaking research that has been carried out by our customers in our Paper of the Month posts.

This month’s paper attempts to overcome the poor tabletability of lamotrigine to facilitate direct compression. To do this the authors explore the powder and tableting properties of various forms of lamotrigine including using a Gamlen D-series to analyse their compaction behaviours.

  • Several forms of lamotrigine and two drug-drug cocrystals were synthesised.
  • The powder properties and compaction behaviour of the resultant powders were characterised. This included carrying out Heckel analysis.
  • Computational analysis of the crystal structures was carried out and the most likely slip planes were identified.
  • The two drug-drug crystals of lamotrigine with nicotinamide and valproic acid demonstrated superior flowability and tabletability over lamotrigine.
  • The valproic cocrystal displayed the best tableting properties, which may be attributed to the presence of slip planes in its crystal structure.


The results of this study show that the tableting properties of lamotrigine can be improved through the formation of multidrug crystals. This approach reduces the amount of excipients required in a tablet allowing smaller tablets to be manufactured.