Bioglasses: glasses for medical applications

bioglasses for medical application

SiO2-CaO-P2O5 bioactive glasses: A promising curcuminoids delivery system

In this paper, we report the study of the loading and the release of curcuminoids by bioactive glasses (BG) and mesoporous bioactive glasses (MBG). Through a detailed spectroscopic study, it was possible to determine the amount and the type of molecules released in water and in simulated body fluid (SBF). In particular, curcumin and K2T21 show a good ability to be released in di-keto and keto-enolic form, depending from the pH. However, after 24 h, the amount of pristine curcumin release is very low with a consequent increment of degradation products derived by curcuminoids. The presence of -OH groups on curcuminoids is a fundamental pre-requisite in order to obtain a high loading and release in polar solution such as water and SBF. The substrate on which we loaded the drugs does not seem to affect significantly the loading and the release of the drugs. The environment, instead, affects the release: for all the drugs, the release in SBF, buffered at pH of 7.4, is slightly worse than the release in water (basic pH values)

The effect of composition on structural, thermal, redox and bioactive properties of Ce-containing glasses

The effect of phosphate on the ability of Ce-containing bioactive glasses to inhibit oxidative stress was studied on compositions based on Hench (46.2%SiO224.3%Na2O26.9ÊO2.6P2O5, mol%) and Kokubo (50.0%SiO225.0%Na2O25.0ÊO) glasses. In particular, the reduction of catalase mimetic activity of Ce-containing glasses due to the presence: i) of P2O5 in the glass compositions, and ii) of phosphate groups in the solution employed for catalase mimetic activity tests was explained and rationalized by combining SEM, XPS, XRD, DTA, FT-IR and UV-vis experiments with Molecular Dynamics simulations.The results suggest that the Ce ions play a different structural role in the two series of glasses. In particular, in phosphate free glasses Ce is coordinated by non-bridging oxygens (NBOs) originated from the disruption of the silicate network, whereas in phosphate containing glasses the NBOs around Ce ions belong to orthophosphate groups. The latter groups stabilize the Ce3+ species subtracting them from the interconversion process between Ce3+ and Ce4+, which is of fundamental importance for the exhibition of the catalase mimetic activity

COORDINATION BEHAVIOR OF SULFA-DRUGS - SYNTHESIS, STRUCTURAL, AND SPECTROSCOPIC INVESTIGATION ON M(II) (N(1)-PYRIMIDIN-2YL-SULFANILAMIDO)2. X H2O

Co(II), Ni(II), Zn(II), and Cd(II) complexes of sulfadiazine (HSD) were prepared and characterized by spectroscopic data. For [Cd(SD)2].2H2O the crystal and molecular structure is reported. The compound crystallizes in the monoclinic C2/c space group with Z = 4, in a cell of dimensions a = 1.9.879(3), b = 8.730(3), c = 16.538(3) angstrom, beta = 122.15(2)degrees. Least-squares refinement of 2019 reflections [I greater-than-or-equal-to 2sigma(I)] gave a final R = 0.034. The structure consists of a monodimensional polymeric chain running along the b axis in which the cadmium atom is coordinated to two sulfonamido and two amino nitrogens from four symmetry-related SD anions. The coordination geometry around the metal is distorted tetrahedral. Hydrogen bonds involving the water molecule contribute to crystal stability

SIDE-CHAIN EFFECT ON THE COORDINATION BEHAVIOR OF GLYCINE DERIVATIVES TOWARD COPPER(II) - CRYSTAL-STRUCTURE OF BIS(MU-N-TRITYLGLYCINATO-O)-BIS[(2,2'-BIPYRIDINE)(N-TRITYLGLYCINATO-O)COPPER(II)]

The crystal and molecular structure of the 2,2'-bipyridine (bipy) adduct of the violet copper(II) complexes with N-triphenylmethylglycine is reported. The structure consists of disceret dimeric [Cu(tglyO)2(bipy)2]2 with CuN2Os chromophores. The metal atoms are bridged through two unidentate carboxylate oxygens

N-(ARYLSULFONYL)GLYCINES AS CYCLOMETALATING LIGANDS - CRYSTAL AND MOLECULAR-STRUCTURES OF DISODIUM BIS(MU-CHLORO)BIS[MU-N-(PHENYLSULFONYL)GLYCINATO-O,N,C]-BIS[MU-N-(PHENYLSULFONYL)GLYCINATO-O,O']TETRAPALLADATE(II) HEXAHYDRATE AND DISODIUM BIS(MU-CHLORO)BI

The interaction of N-(phenylsulfonyl)- and N-(4-tolylsulfonyl)- (N-tosyl hereafter) glycine (Bsgly and Tsgly, respectively) with Pd(II) ion at pH congruent-to 3.5 gives rise to cyclometalation reactions leading to complexes of the formulas Na2[Pd4Cl2(Bsgly-O,N,C)2(Bsgly-O,O')2].6H2O (I) and Na2[Pd4Cl2(Tsgly-O,N,C)(Tsgly-O,O')]2.4.5H2O.2TsglyH (II) (Bsgly-O,N,C and Tsgly-O,N,C = O,N,C-bonded ligand; Bsgly-O,O' and Tsgly-O,O' = carboxylate bridging ligand; TsglyH = neutral N-tosylglycine). The complexes crystallize in the triclinic P1BAR space group with a = 13.469 (4) angstrom, b = 13.636 (4) angstrom, c = 15.005 (5) angstrom, alpha = 70.94 (2)-degrees, beta = 66.32 (2)-degrees, gamma = 88.59 (2)-degrees, and Z = 2 for I and a = 17.058 (1) angstrom, 18.897 (2) angstrom, c = 13.194 (1) angstrom, alpha = 94.61 (1)-degrees, beta = 107.98 (1)-degrees, gamma = 74.32 (1)-degrees, and Z = 2 for II. Both structures consist of two tetrameric units, symmetry generated from two independent [Pd2Cl(L-O,N,C)(L-O,O')] (L = Bsgly or Tsgly) monoanions. In each tetramer one Pd(II) atom is coordinated with the deprotonated sulfonamide nitrogen and the carbon atom of the aromatic ring in the ortho position to the sulfonyl group of a ligand molecule, the bridging chlorine atom, and one oxygen atom of a bridging carboxyl from a second ligand molecule. The other crystallographically independent Pd(II) atom is coordinated with the other oxygen of the bridging carboxyl, the chlorine atom, the deprotonated sulfonamide nitrogen, and the oxygen atom of a monodentate carboxylate group forming a N,O-chelate glycine-like ring. Both of the Pd(II) atoms show a slightly distorted square-planar coordination geometry. Infrared and NMR results are also reported

Synthesis and spectroscopic properties of some thermochromic copper(II) complexes of N-(2-aminoethyl) heterocyclic derivatives.

Some copper(II) complexes with heterocyclic amine were prepared and characterized by means of spectroscopic and magnetic measurements

Solution and solid state investigation ofthe Cu(II)-N-acetyl-L-glutamine system and its N-methylimidazole adduct.

The interactions of N-acetyl-L-glutamine (AcglnH) with copper(II) ion in aqueous and water-methanol (50% v/v) solutions and in solid state have been investigated. It was found that the N-acetyl-L- glutaminate anion (Acgln) is unable to form stable complexes in solution on varying the pH values, before copper(II) hydroxyde precipitation occurs. In the solid state two compounds of the formulas Cu(Acgln)2·2H2O and Cu(Acgln)2(MeIm)2·2H2O (MeIm = N-methylimidazole) are separated; for the latter complex the crystal and molecular structure was determined by means of the single crystal X-ray diffraction method. The compound crystallizes in the monoclinic space group C2, with cell dimensions: a = 15.606(7), b = 7.353(2), c = 13.951(2) Å, β = 110.69(3)° and Z = 2. The structure was solved by conventional Patterson and Fouder methods and refined by full-matrix least-squares to an R value of 0.026. The structure consists of [Cu(Acgln)2(Me- Im)2] units and uncoordinated watet molecules. The Cu(II) atom lying on the twofold axis exhibits a square-planar N2O2 environment from ligation by two symmetry-related carboxytate oxygens and N-methylimidazole nitrogens. The second non- bonding carboxylate oxygens are 2.813(3) Å from the Cu(II) atom and both are placed under the coordination plane. Spectroscopic and thermal results agree with the crystal stmcture, while for binary Cu(Acgln)2·2H2O a CuO4 chromophore is suggested