DFT based Experimental investigations on the spectroscopic properties, molecular structure, and biological activity of a glucocorticoid steroid, Prednisolone

Abstract

This study presents a comprehensive investigation into Prednisolone, a glucocorticosteroid drug, through vibrational analysis and DFT based quantum chemical calculations. Utilizing the DFT-B3LYP functional at the basis set 6-311++G(d,p), the research explores conformational and geometric aspects, harmonic vibrational wavenumbers, and FMO analysis. The phase angle of pseudo rotation is measured to predict the molecule's conformation. FT-IR and Raman spectra were analyzed and found that the lowering of symmetric stretching vibrations of O25-H53 and O24-H52 to 3470 and 3362 cm−1 respectively, is due to the presence of intra/intermolecular hydrogen bonding. Topology analysis (AIM, NCI,ELF, LOL) global chemical reactivity descriptor study, Hirshfeld surface analysis and electron excitation studies provide a detailed understanding of Prednisolone's molecular properties. AIM analysis proved the possibility of a strong hydrogen bond H53…….O24, because it has the minimum bond length of 1.9645 Å, accompanied by a maximum ρ value of 0.0255 a.u. The hydrogen bond O24…….H53 —– O25, indicated by blue RDG isosurfaces in NCI, with value of sign (λ2) ρ between -0.02 to -0.05 a.u, is predicted to be strong. Bandgap energy of the molecule calculated from HOMO-LUMO is 4.7105. This is well agreement with the results obtained from experimental UV-visible spectra. Molecular docking study, Drug likeness parameter analysis and ADMET properties helps in predicting the anti-inflammatory activity of the molecule.