Molecular surface comparison. 2. Similarity of electrostatic vector fields in drug design.

In the first article of this series a real-time graphics method was described for molecular similarity of scalar properties. This has now been extended for the comparison of molecular vector properties, most notably electrostatic field. A comparison of the various techniques of calculating fields is presented that includes a new method based on natural orbital fitted point charges. In the two examples described, namely, a series of benzodiazepine agonists and a set of serotonin 5-HT3 antagonists, the program has been shown to produce useful pharmacophoric overlaps that can be used in the design of novel therapeutic agents.