Routes to drug design via bioisosterism of carboxyl and sulfonamide groups

Aim: The similarity in the biological function of the bioisosteric pair, carboxyl and sulfonamide functional groups, is studied using the quantitative tool, average electron density of the bioisosteric moiety in drug molecules and the qualitative tool, electrostatic potential. Results/methodology: Five different capping groups (methyl, phenyl, chlorine, hydrogen and amine) were considered to investigate the effect of the environment on the properties of the bioisosteres. The molecules were considered in their neutral and anionic forms to account for the change in pH depending on the medium of the drug-receptor interactions. Conclusion: The new developed approach, average electron density, is not only advantageous as a qualitative descriptor, it is also more consistent compared with the conventionally accepted method, electrostatic potential, especially for the anions.