Tautomerism is the phenomenon wherein a molecule can exist in multiple isomeric forms, rapidly interconverting through the migration of protons or other atoms, and these various tautomeric forms possess distinct structures and electronic configurations, ultimately influencing the overall chemical reactivity and properties of the molecule. This phenomenon observed in numerous drugs, is intricately linked to MESP, particularly in comprehending their interactive behaviour . When drug molecules exhibit multiple tautomeric forms, the challenge lies in determining the form for which the MESP should be computed . The more stable form of the molecule is used to establish correlations between MESP and drug activity. Figure shows the tautomeric structures of an anti-viral drug favipiravir and their MESP density plots drawn at 0.005 au. The nucleophilic area extends to the group of hydroxyls via carbonyl oxygen, hydroxyl oxygen, and pyrazine ring nitrogen significant class of pharmaceutical compounds, display similarity in their stability .