Studying the interaction of calcium, potassium and sodium ions with 3 isomers of Docetaxel drug and the effect of these ions on physicochemical and thermodynamical properties: A DFT computation

In this study, the interaction of Ca2+, K+ and Na+ ions along with 3 isomers of Docetaxel drug and their physical and thermodynamic properties have been computed and investigated using DFT method calculations. These calculations are based on B3LYP quantum chemical level and at 6-311G** basis orbital set. The proximity of ions has been studied in order to determine physical and thermodynamic properties. Approaching the ions to Docetaxel drug causes different events like changing angles between bonds, bond lengths, shape and orbital energy levels and other physicochemical characteristics. DOS graphs have been plotted to obtain some quantum chemical data. The results have shown that the HOMO orbitals, are localized around the C-C bonds, whereas the LUMO orbitals are more localized around the oxygen and nitrogen atoms of Docetaxel. The obtained results show that these metallic cations tend to stay in the suitable spatial situations to diminish their own density of electrical charge. When one of the ions approached the drug, the orbitals change in terms of shape and energy, and will fit to the new situation. Accordingly, the obtained results show that the absolute values of ΔE, ΔG and ΔH have the order of Drug-K + Drug-Na+ Drug-Ca2+, and the values of EHOMO, ELUMO, η, μ, ΔNmax and S have the order of K+ ≈ Na+ Ca2+ .