Search results for "Hydrazide"

PREPARATION AND IN VITRO CHARACTERIZATION OF NEW HYDROGELS BASED ON INULIN AND ALPHA,BETA-POLYASPARTYLHYDRAZIDE FOR COLONIC DRUG DELIVERY

2008

A Discrete μ 4 ‐Oxido Tetranuclear Iron(III) Cluster

2012

Reaction of a Schiff base ligand derived from salicyloyl hydrazide and diacetyl monooxime (H2L) with a triangular μ3-oxido-centered [Fe3(μ3-O)]7+ core yields a new tetranuclear iron(III) complex. FeIII4(μ4-O) crystallizes in the triclinic space group P. Structural studies reveal that this tetranuclear iron(III) complex is a new structure type of an uncharged (alkoxido)(oxido)iron(III) cluster in which the four iron(III) ions are located at the corners of a distorted tetrahedron. A study of the magnetic properties supports the presence of antiferromagnetic interactions through the central μ4-oxido ion as well as the μ2-methoxy groups present, giving an an S = 0 ground state. Mossbauer spectr…

Spectroscopic, density functional theory, nonlinear optical properties and in vitro biological studies of Co(II), Ni(II), and Cu(II) complexes of hyd…

2021

Coordinatively Unsaturated Lanthanide(III) Helicates: Luminescence Sensors for Adenosine Monophosphate in Aqueous Media

2016

Coordinatively unsaturated double-stranded helicates [(H2 L)2 Eu2 (NO3 )2 (H2 O)4 ](NO3 )4 , [(H2 L)2 Tb2 (H2 O)6 ](NO3 )6 , and [(H2 L)2 Tb2 (H2 O)6 ]Cl6 (H2 L=butanedioicacid-1,4-bis[2-(2-pyridinylmethylene)hydrazide]) are easily obtained by self-assembly from the ligand and the corresponding lanthanide(III) salts. The complexes are characterized by X-ray crystallography showing the helical arrangement of the ligands. Co-ligands at the metal ions can be easily substituted by appropriate anions. A specific luminescence response of AMP in presence of ADP, ATP, and other anions is observed. Specificity is assigned to the perfect size match of AMP to bridge the two metal centers and to replac…

Macromolecular Prodrugs Based on Synthetic Polyaminoacids: Drug Delivery and Drug Targeting in Antitumor Therapy

2011

In the last twenty years a depth study on potential pharmaceutical applications of synthetic polymers at proteinlike structure as carrier for macromolecular prodrug production has been performed in academia and in industry. In particular α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), α,β-polyaspartylhydrazide (PAHy), poly(glutamic acid) (PGA), poly(aspartic acid) (PAA) and polylysine (PLL) have been extensively studied in this field. In the present review, the use of PHEA, PAHy, PGA as starting materials to prepare macromolecular prodrugs is reported and drug delivery and targeting aspects have been considered.

NEW SELF-ASSEMBLING POLYASPARTYLHYDRAZIDE COPOLYMER MICELLES FOR ANTICANCER DRUG DELIVERY.

2010

A new amphiphilic copolymer have been synthesized starting from the hydrosoluble polyaspartylhydrazide (PAHy) polymer, by grafting both hydrophilic PEG(2000) chains and hydrophobic palmitic acid (C(16)) moieties on polymer backbone, and the structure of obtained PAHy-PEG(2000)-C(16) copolymer have been characterized by 2D (1)H/(13)C NMR experiments. PAHy-PEG(2000)-C(16) copolymer showed the ability of self-assembling in aqueous media giving a core-shell structure and resulted potentially useful for encapsulating and dissolving hydrophobic drug. The formation of micellar core-shell structure has been investigated by 2D (1)H NMR NOESY experiments. The presence of cross-peaks for protons of C(…

Disulfide-crosslinked hyaluronan-gelatin hydrogel films: a covalent mimic of the extracellular matrix for in vitro cell growth

2003

A new disulfide crosslinking method was developed for the preparation of blended hyaluronan (HA)-gelatin hydrogels to form a synthetic, covalently linked mimic of the extracellular matrix (ECM). The HA and gelatin were chemically modified using 3,3′-dithiobis(propionic hydrazide) (DTP). After reduction with dithiothreitol (DTT), the thiol derivatives of HA (HA-DTPH) and gelatin (gelatin-DTPH) were obtained and characterized. To minimize interference with biological function, the degree of substitution of HA-DTPH and gelatin-DTPH was kept below 50%. Solutions of HA-DTPH and gelatin-DTPH in varying blends (20%, 40%, 60%, 80% gelatin) were prepared in 1% w/v NaCl and crosslinked by disulfide b…

Scaffolds based on hyaluronan crosslinked with a polyaminoacid: Novel candidates for tissue engineering application

2008

New porous scaffolds, with a suitable hydrolytic and enzymatic degradation, useful for tissue engineering applications have been obtained by a carbodiimide mediated reaction between hyaluronan (HA) and a synthetic polymer with a polyaminoacid structure such as α,β-polyaspartylhydrazide (PAHy). Scaffolds with a different molar ratio between PAHy repeating units and HA repeating units have been prepared and characterized from a chemical and physicochemical point of view. Tests of indirect and direct cytotoxicity, cell adhesion, and spreading on these biomaterials have been performed by using murine L929 fibroblasts. The new biomaterials showed a good cell compatibility and ability to allow ce…

CCDC 1880657: Experimental Crystal Structure Determination

2021

Related Article: Ramadan M. Ramadan, Samir M. El���Medani, Abdelmoneim Makhlouf, Hussein Moustafa, Manal A. Afifi, Matti Haukka, Ayman Abdel Aziz|2021|Appl.Organomet.Chem.|35|e6246|doi:10.1002/aoc.6246

Pyrazole amino acids: hydrogen bonding directed conformations of 3-amino-1H-pyrazole-5-carboxylic acid residue

2017

A series of model compounds containing 3-amino-1H-pyrazole-5-carboxylic acid residue with N-terminal amide/urethane and C-terminal amide/hydrazide/ester groups were investigated by using NMR, Fourier transform infrared, and single-crystal X-ray diffraction methods, additionally supported by theoretical calculations. The studies demonstrate that the most preferred is the extended conformation with torsion angles ϕ and ψ close to ±180°. The studied 1H-pyrazole with N-terminal amide/urethane and C-terminal amide/hydrazide groups solely adopts this energetically favored conformation confirming rigidity of that structural motif. However, when the C-terminal ester group is present, the second con…