Theoretical insights of the drug-drug interaction between favipiravir and ibuprofen: a DFT, QTAIM and drug-likeness investigation.

One of the approaches adopted, as the first treatment method, in previous pandemic viruses before the production of new vaccines or drugs, is to evaluate the effectiveness of existing drugs. Sometimes, it is known that the combination of drugs provides better treatment by increasing the activity of the drugs due to mutual interactions. In this work, we used quantum theory of atoms in molecules and density functional theory to examine the structure and activity relationship between Favipiravir (FPV), a potential antiviral drug for ribonucleic acid viruses, and an inhibitor of influenza virus, and Ibuprofen (IBP), a nonsteroidal anti-inflammatory drug. The drug-likeness evaluations of IBP…FPV were also performed. It was observed that FPV and IBP interact in several ways via hydrogen bonding (HB) leading to changes in the activities of the combined drug and IBP…FPV is predicted to be orally bioavailable. It was also found that the highest occupied molecular orbital (HOMO) is located on IBP and the lowest unoccupied molecular orbital (LUMO) is distributed over FPV. The biological activity of the combined drug system is increased because of the small HOMO-LUMO energy gap value, partially covalent and non-covalent HB interactions.Communicated by Ramaswamy H. Sarma.

DFT, FT-Raman and FT-IR investigations of 1-cyclobutylpiperazine.

FT-IR and FT-Raman spectra of 1-cyclobutylpiperazine (1cbpp) have been experimentally reported in the region of 4000-10 cm(-1) and 4000-50 cm(-1), respectively. The optimized geometric parameters, conformational equilibria, normal mode frequencies and corresponding vibrational assignments of 1cbpp (C(8)H(16)N(2)) are theoretically examined by means of B3LYP hybrid density functional theory (DFT) method together with 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments have been made on the basis of potential energy distribution (PED) and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1cbpp have been predicted. Calculations are employed for four different conformations of 1cbpp, both in gas phase and in solution. Solvent effects are investigated using chloroform and dimethylsulfoxide. All results indicate that B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and the structural parameters, vibrational frequencies and assignments, IR and Raman intensities of 1cbpp are solvent dependent.

FT-IR and Raman spectroscopic and quantum chemical investigations of some metal halide complexes of 1-phenylpiperazine.

New metal halide complexes in the form of M(pp)(2)Cl(2) (where pp=1-phenylpiperazine and M=Pd or Hg) have been prepared for the first time and their FT-IR and FT-Raman spectra are reported in the region of 4000-10 cm(-1) and 4000-50 cm(-1), respectively. The optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of the present compounds are theoretically examined by means of B3LYP hybrid density functional theory (DFT) method together with Lanl2dz basis set. Furthermore, reliable vibrational assignments made on the basis of potential energy distribution (PED) were calculated and the thermodynamics functions, the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) of these compounds have been predicted. According to the results, theoretical values have been successfully compared against experimental data.