A new set of simple empirical rules for drug design that avoids any 'wet' chemistry or complicated calculations has been mooted by chemists in Cambridge, UK.

A new set of simple empirical rules for drug design that avoids any ’wet’ chemistry or complicated calculations has been mooted by chemists in Cambridge, UK.

Rather than experimenting in the lab, or performing modelling calculations, Samuel Motherwell and collaborators have searched the Cambridge structural database (CSD), the world repository of small molecule crystal structures, in their quest to find counterions that can be used to modify a drug’s physical properties by making a salt of it.

Their specific aim was to find a robust hydrogen bonding motif in organic sulfonate salts. Motherwell explains that a robust motif will ’recur frequently in the CSD despite competition from other hydrogen bonding groups, indicating that the motif is energetically stable, and crystals are easily obtained under ambient conditions’.

A robust ring with a sulfonate anion and a bidentate nitrogen-containing group was identified. The next step is to devise rules to predict whether it might appear in new structures. This new approach will help the pharmaceutical industry predict suitable salts and shorten the drug design process.

Colin Batchelor

References

D A Haynes et al, CrystEngComm, 2004, 6, 584 <MAN>b413797c</MAN>