Voltage-Dependent Sodium Channel Blocker Anticonvulsants: An Approach to the Structure-Activity Relationship

Abstract

Background: Anticonvulsants are drugs used in the treatment of seizures; their pharmacology includes promoters of brain inhibition and inhibitors of brain activity. Of the latter, voltagedependent sodium channel blockers (VGSCB) are the most widely used in therapeutics.

Objective: The study aimed at proposing the structural requirements of VGSC blockers through a quantitative structure-activity relationship analysis of drugs with proven activity.

Methods: IC₅₀ values of anticonvulsant drugs on VGSCs were considered under similar experimental conditions; some physicochemical properties of the molecules that were correlated with their biological activity were determined in silico.

Results: Relationships were observed between the dipole moment, pK_a, E_HOMO, and MR with the biological activity, which infers that between greater polarity and basicity of the drugs, their activity as blockers will increase. Subsequently, the structural subclassification of the drugs was carried out, based on the urea derivation, the groups of which were: Group 1 (direct and bioisostere derivatives) and Group 2 (homologue and vinylogue derivatives of urea).

Conclusion: The biological activity depends on the polarity, basicity, and electronic density of the drugs. The derivation of urea is essential, which is present in its original substituted form or a bioisosteric form. Urea can be in the form of a homologue or a vinylogue at the ends of the molecule. Aromatic substitution to the urea portion is necessary.

Keywords: Anticonvulsants; ICsub50; QSAR; SAR; pharmacophore.; voltage-gated sodium channel blockers.