Spectroscopic and computational study of Favipiravir-Adenine cocrystallization biomolecular complex

Abstract

The research focuses on the structural investigation of biomolecules and biomolecular complexes using the DFT method, spectroscopic techniques, and determining cocrystal formation. The significant difficulties in making new drug products are low oral bioavailability and poor aqueous solubility. However, the co-crystallization of biomolecules can enhance their solubility without changing their pharmacological properties. The optimized structure of the molecules is obtained using the B3LYP/6–311++G(d,p) basis set within the framework of Density Functional Theory (DFT). Various vibrational techniques such as Fourier Transform Infrared (FTIR), Raman, and Surface-Enhanced Raman Spectroscopy (SERS) are employed to characterize the monomers and their interacting system. Possible vibrational assignments along with Potential energy distribution (PED) analysis are carried out using Vibrational Energy Distribution Analysis (VEDA). Natural Bond Orbital (NBO), Non-Linear Optical (NLO), Non-Covalent Interaction (NCI), and Atoms in Molecule (AIM) study are carried out to understand the interacting mechanism in the Favipiravir-Adenine biomolecular complex. The study shows that there is charge transfer through inter and intramolecular interaction in the complex. The binding energy of protein and Ligand is investigated using the Autodock tool for the molecular docking method and the negative value of binding energy – 4.36 kcal/mol of Favipiravir-Adenine biomolecular complex exclaims good binding affinity with the chosen protein 6LU7. Lipinski's criteria for druglikeness also claim that monomers and synthesized biomolecular complexes have the potential to influence drugs with good oral bioavailability. Cocrystal formation is confirmed by the X-ray diffraction pattern. The Protox II software claims that the toxicity of the drug and synthesized biomolecular complex is class IV.