SYNTHESIS, CHARACTERIZATION, BSA BINDING ACTIVITY AND ADME PREDICTIONS OF A NEW Co(II) COMPLEX WITH O-VANILLIN-BASED SCHIFF BASE LIGAND

This study reports the synthesis, structural characterization, bovine serum albumin (BSA) binding activity, and pharmacokinetic properties of an o-vanillin-based Schiff base ligand and its Co(II) complex. The ligand (H2L) was synthesized via condensation reaction between isonitrosophenyl hydrazine and o-vanillin, and the Co(II) complex [Co(HL)2] was prepared by reacting the ligand with cobalt(II) acetate monohydrate. The ligand was characterized by elemental analysis, UV-Vis, FTIR, NMR spectroscopy, while Co(II) complex was characterized by elemental analysis, UV-Vis, magnetic susceptibility, FTIR and mass spectrometry, confirming successful complex formation with octahedral geometry. BSA binding studies of Co(II) complex demonstrated moderate binding (Kbin=8.74x103 M-1) via static quenching mechanism, supported by thermodynamic calculations (ΔG=-22.49 kJ.mol-1). The ligand also exhibited BSA binding with a lower affinity (Kbin=1.36x103 M-1), indicating that metal coordination significantly enhances protein interaction. In silico ADME predictions of Co(II) complex indicated promising pharmacokinetics characterized by a molecular weight of 651.53 g/mol, polar surface area (TPSA = 151.54 Ų), moderate flexibility, and reasonable physicochemical stability. However, limited gastrointestinal absorption and lack of blood-brain barrier permeability, suggest potential suitability for peripheral therapeutic applications. Future studies will involve detailed cytotoxicity assays and pharmacokinetic evaluations to validate the therapeutic efficacy and safety profile of this promising Co(II) complex and Schiff base ligand.