Spectroscopic, thermal and X-ray structural study of the antiparasitic and antiviral drug nitazoxanide

Biological efficacy of novel metal complexes of Nitazoxanide: Synthesis, characterization, anti-COVID-19, antioxidant, antibacterial and anticancer activity studies

It has been repeatedly reported that nitazoxanide (NTZ) exhibits a wide range of antiviral activities against various viral infections and has shown antimicrobial properties against anaerobic bacteria, helminths and protozoa. To improve these properties, three novel metal complexes were synthesized. The bidentate characteristic of the NTZ ligand was characterized by different spectroscopic techniques, including Fourier transform infrared (FT-IR), thermogravimetric, nuclear magnetic resonance (NMR) and UV - visible spectroscopy. The geometries of the formed compounds were evaluated by density functional theory, and the results revealed that NTZ-Ru(III) has an octahedral geometry, while NTZ-Au(III) and NTZ-Ag(I) complexes have distorted square planar structures. Binding between the metal complexes and calf thymus DNA (Ct-DNA) has been studied via absorption spectra. Moreover, human albumen serum (HAS) titration has been carried out to test their susceptibility to interact with a major target molecule via absorption and fluorescence spectroscopic techniques. Several in vitro bioassays were performed to evaluate the biological activity, antibacterial potency against E. coli, antioxidant activity and cytotoxicity of the ligand and the obtained complexes. The results showed that complexes Ru(III) and Au(III) have the highest radical scavenging percentage while the Ag(I) demonstrated the greatest antibacterial activity. Moreover, the metal complexes presented potentially effective against E. coli. Furthermore, compared with NTZ-Ag and the free ligand, the in vitro cytotoxicity assay showed that both NTZ-Ru(III) and NTZ-Au(III) exhibited significant anticancer activity against HeLa cells. The efficiency of the novel compounds as antivirals was tested by molecular docking with two COVID-19 receptors to obtain all interaction details.

Cocrystals and alloys of nitazoxanide: enhanced pharmacokinetics

The pharmaceutical cocrystal alloy of NTZ-PABA : NTZ-PASA (0.75 : 0.25) exhibits a higher pharmacokinetic profile than the individual cocrystals and nitazoxanide.

Crystal structure of 2-nitro-N-(5-nitro-1,3-thia-zol-2-yl)benzamide

In the title compound, C₁₀H₆N₄O₅S, the mean plane of the non-H atoms of the central amide fragment C—N—C(=O)—C [r.m.s. deviation = 0.0294 Å] forms dihedral angles of 12.48 (7) and 46.66 (9)° with the planes of the thia­zole and benzene rings, respectively. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming chains along [001]. In addition, weak C—H⋯O hydrogen bonds link these chains, forming a two-dimensional network, containing R⁴₄(28) ring motifs parallel to (100).

Tizoxanide pyridine monosolvate

IN THE TITLE COMPOUND [SYSTEMATIC NAME: 2-hy-droxy-N-(5-nitro-1,3-thia-zol-2-yl)benzamide pyridine monosolvate], C(10)H(7)N(3)O(4)S·C(5)H(5)N, the dihedral angle between the pyridine and benzamide rings is 80.55 (7)°. An intamolecular O-H⋯N hydrogen bond occurs in the tizoxanide. In the crystal, the components are linked by an O-H⋯N hydrogen bond, forming a zigzag chain along the c axis. Aromatic π-π inter-actions between inversion-related pyridine rings [centroid-centroid distance = 3.803 (6) Å] are also observed.