Structural and thermal characterization of ternary complexes of piroxicam and alanine with transition metals: uranyl binary and ternary complexes of piroxicam. Spectroscopic characterization and properties of metal complexes

Synthesis, spectral, DFT modeling, cytotoxicity and microbial studies of novel Zr(IV), Ce(IV) and U(VI) piroxicam complexes

The Zr(IV), Ce(IV) and U(VI) piroxicam anti-inflammatory drug complexes were prepared and characterized using elemental analyses, conductance, IR, UV-Vis, magnetic moment, ^IHNMR and thermal analysis. The ratio of metal: Pir is found to be 1:2 in all complexes estimated by using molar ratio method. The conductance data reveal that Zr(IV) and U(VI) chelates are non-electrolytes except Ce(IV) complex is electrolyte. Infrared spectroscopic confirm that the Pir behaves as a bidentate ligand co-ordinated to the metal ions via the oxygen and nitrogen atoms of ν(CO)_carbonyl and ν(CN)_pyridyl, respectively. The kinetic parameters of thermogravimetric and its differential, such as activation energy, entropy of activation, enthalpy of activation, and Gibbs free energy evaluated using Coats-Redfern and Horowitz-Metzger equations for Pir and complexes. The geometry of the piroxicam drug in the Free State differs significantly from that in the metal complex. In the time of metal ion-drug bond formation the drug switches-on from the closed structure (equilibrium geometry) to the open one. The antimicrobial tests were assessed towards some types of bacteria and fungi. The in vitro cell cytotoxicity of the complexes in comparison with Pir against colon carcinoma (HCT-116) cell line was measured.

Towards improved solubility of poorly water-soluble drugs: cryogenic co-grinding of piroxicam with carrier polymers

Amorphous solid dispersions (SDs) open up exciting opportunities in formulating poorly water-soluble active pharmaceutical ingredients (APIs). In the present study, novel catalytic pretreated softwood cellulose (CPSC) and polyvinylpyrrolidone (PVP) were investigated as carrier polymers for preparing and stabilizing cryogenic co-ground SDs of poorly water-soluble piroxicam (PRX). CPSC was isolated from pine wood (Pinus sylvestris). Raman and Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used for characterizing the solid-state changes and drug-polymer interactions. High-resolution scanning electron microscope (SEM) was used to analyze the particle size and surface morphology of starting materials and final cryogenic co-ground SDs. In addition, the molecular aspects of drug-polymer interactions and stabilization mechanisms are presented. The results showed that the carrier polymer influenced both the degree of amorphization of PRX and stabilization against crystallization. The cryogenic co-ground SDs prepared from PVP showed an enhanced dissolution rate of PRX, while the corresponding SDs prepared from CPSC exhibited a clear sustained release behavior. In conclusion, cryogenic co-grinding provides a versatile method for preparing amorphous SDs of poorly water-soluble APIs. The solid-state stability and dissolution behavior of such co-ground SDs are to a great extent dependent on the carrier polymer used.

New metal based drugs: spectral, electrochemical, DNA-binding, surface morphology and anticancer activity properties

The NSAID piroxicam (PRX) drug was used for complex formation reactions with Cu(II), Zn(II) and Pt(II) metal salts have been synthesized. Then, these complexes have been characterized by spectroscopic and analytical techniques. Thermal behavior of the complexes were also investigated. The electrochemical properties of all complexes have been investigated by cyclic voltammetry (CV) using glassy carbon electrode. The biological activity of the complexes has been evaluated by examining their ability to bind to fish sperm double strand DNA (FSFSdsDNA) with UV spectroscopy. UV studies of the interaction of the PRX and its complexes with FSdsDNA have shown that these compounds can bind to FSdsDNA. The binding constants of the compounds with FSdsDNA have also been calculated. The morphology of the FSdsDNA, PRX, metal ions and metal complexes has been investigated by scanning electron microscopy (SEM). To get the SEM images, the interaction of compounds with FSdsDNA has been studied by means of differential pulse voltammetry (DPV) at FSdsDNA modified pencil graphite electrode (PGE). The decrease in intensity of the guanine oxidation signals has been used as an indicator for the interaction mechanism. The effect of proliferation PRX and complexes were examined on the HeLA and C6 cells using real-time cell analyzer with four different concentrations.

Coordination modes of bidentate lornoxicam drug with some transition metal ions. Synthesis, characterization and in vitro antimicrobial and antibreastic cancer activity studies

The NSAID lornoxicam (LOR) drug was used for complex formation reactions with different metal salts like Cr(III), Mn(II), Fe(III) and Ni(II) chlorides and Fe(II), Co(II), Cu(II) and Zn(II) borates. Mononuclear complexes of these metals are obtained that coordinated to NO sites of LOR ligand molecule. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, IR, UV-Vis, (1)H NMR, mass, electronic spectra, magnetic susceptibility and ESR spectral studies, conductivity measurements, thermogravimetric analyses (TG-DTG) and further confirmed by X-ray powder diffraction. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. The data show that the complexes have composition of ML2 type except for Fe(II) where the type is [ML3]. The electronic absorption spectral data of the complexes suggest an octahedral geometry around the central metal ion for all the complexes. The antimicrobial data reveals that LOR ligand in solution show inhibition capacity less or sometimes more than the corresponding complexes against all the species under study. In order to establish their future potential in biomedical applications, anticancer evaluation studies against standard breast cancer cell lines (MCF7) was performed using different concentrations. The obtained results indicate high inhibition activity for Cr(III), Fe(II) and Cu(II) complexes against breast cancer cell line (MCF7) and recommends them for testing as antitumor agents.

Synthesis, spectroscopic, thermal and DFT calculations of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid binuclear metal complexes

The binuclear complexes of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid ligand (HL) with Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions were prepared and their stoichiometry was determined by elemental analysis. The stereochemistry of the studied series of metal complexes was established by analyzing their infrared, (1)H NMR spectra and the magnetic moment measurements. According to the elemental analysis data, the complexes were found to have the formulae [Fe2L(H2O)8]Cl5 and [M2L(H2O)8]Cl3 (M=Co(II), Ni(II), Cu(II) and Zn(II)). The present analyses demonstrate that all metal ions coordinated to the ligand via O(9), O(11), N(16) and N(18) atoms. Thermal decomposition studies of the ligand-metal complexes have been performed to verify the status of water molecules present in these metal complexes and their general decomposition pattern. Density Functional Theory (DFT) calculations at the B3LYP/6-31G(*) level of theory have been carried out to investigate the equilibrium geometry of the ligand and complexes. Moreover, charge density distribution, extent of distortion from regular geometry, dipole moment and orientation have been performed and discussed.

Complex formation of uranium(VI) with L-phenylalanine and 3-phenylpropionic acid studied by attenuated total reflection Fourier transform infrared spectroscopy

Uranyl complexes with phenylalanine and the analogous ligand phenylpropionate were investigated in aqueous solution by attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The assignment of the observed bands to vibrational modes was accomplished using spectra of the pure ligands recorded at different pH values and spectra of the 15N labeled analogous compounds of the amino acid. The results presented in this work provide a detailed description of the binding states of the uranyl complexes in solution. A bidentate binding of the carboxylate group to the actinide ion was observed by the characteristic shifts of the carboxylate modes. From the spectra the presence of the protonated amino group in the actinide complex can be derived. Due to these findings, contributions of the amino group to the binding to the uranyl ion in the amino acid complex can be ruled out.

Uranyl binary and ternary chelates of tenoxicam Synthesis, spectroscopic and thermal characterization of ternary chelates of tenoxicam and alanine with transition metals

Ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) chelates with tenoxicam (Ten) drug (H(2)L(1)) and dl-alanine (Ala) (HL(2)) and also the binary UO(2)(II) chelate with Ten were studied. The structures of the chelates were elucidated using elemental, molar conductance, magnetic moment, IR, diffused reflectance and thermal analyses. UO(2)(II) binary chelate was isolated in 1:2 ratio with the formula [UO(2)(H(2)L)(2)](NO(3))(2). The ternary chelates were isolated in 1:1:1 (M:H(2)L(1):L(2)) ratios and have the general formulae [M(H(2)L(1))(L(2))(Cl)(n)(H(2)O)(m)].yH(2)O (M=Fe(III) (n=2, m=0, y=2), Co(II) (n=1, m=1, y=2) and Ni(II) (n=1, m=1, y=3)); [M(H(2)L(1))(L(2))](X)(z).yH(2)O (M=Cu(II) (X=AcO, z=1, y=0), Zn(II) (X=AcO, z=1, y=3) and UO(2)(II) (X=NO(3), z=1, y=2)). IR spectra reveal that Ten behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl-O groups, while Ala behaves as a uninegatively bidentate ligand coordinated to the metal ions via the deprotonated carboxylate-O and amino-N. The magnetic and reflectance spectral data confirm that all the chelates have octahedral geometry except Cu(II) and Zn(II) chelates have tetrahedral structures. Thermal decomposition of the chelates was discussed in relation to structure and different thermodynamic parameters of the decomposition stages were evaluated.