Search results for "Azide"

A Chemosensor Bearing Sulfonyl Azide Moieties for Selective Chromo-Fluorogenic Hydrogen Sulfide Recognition in Aqueous Media and in Living Cells

2014

A simple chemodosimeter based on a sulfonyl azide dye (1-Az), which displayed a highly selective response toward hydrogen sulfide anion in mixed aqueous media, was synthesised and characterised. Addition of hydrogen sulfide to acetonitrile/HEPES 1:1 solutions of 1-Az induced a clear colour change from red-orange to yellow, which was easily detected by the naked eye, and by an enhancement in the emission intensity. Other common anions, thiol-containing biomolecules and oxidants did not induce any noticeable colour or fluorescence modulation in the probe. The chemodosimeter also showed a good sensitivity, with limits of detection of 11.91 and 0.63 μM by using UV/Vis or fluorescence measuremen…

Enhancement of Nitro Reduction in Rat Liver Microsomes by Haemin and Haemoproteins

1978

1. Reductive metabolism of p-nitrobenzoic acid and neoprontosil in rat liver microsomes was studied in the presence of haemin, haemoglobin and myoglobin. 2. Microsomal nitro reduction is enhanced 4-fold in the presence of haemoglobin, whereas azo reduction is not affected. 3. Microsomal nitro reduction is enhanced to a similar extent by haemoglobin, haemin and boiled haemoglobin, whereas myoglobin is about half as active. 4. Maximal enhancement of microsomal nitro reductase activity by haemoglobin is achieved at high substrate concentration (6 mM) and low microsomal protein concentration (0.5--1.0 mg/ml). 5. Control microsomal nitro reduction as well as the haemoglobin-enhanced microsomal n…

Novel cationic polyaspartamide with covalently linked carboxypropyl-trimethyl ammonium chloride as a candidate vector for gene delivery

2006

Abstract The non-viral gene vector properties of a protein-like polymer, the α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) were investigated after its derivatization with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) as molecule bearing cationic groups, in order to obtain stable polycations able to condense DNA. PHEA was firstly functionalized with hydrazide pendant groups by reaction with hydrazine monohydrate (HYD), obtaining the polyhydrazide α,β-poly(N-2-hydroxyethyl/carbazate)- d , l -aspartamide (PHEA–HYD). In this paper we reported that polymer functionalization degree can be easily modulated by varying reaction conditions, so allowing us to produce two PHEA derivatives…

Micellar liquid Chromatographic determination of diuretics by diazotization and coupling with the Bratton-Marshall reagent

1997

Abstract A Chromatographic procedure that uses micellar mobile phases of sodium dodecyl sulphate (SDS) and propanol at pH 3 is reported for the determination, in urine samples, of thiazide diuretics (althiazide, bendroflumethiazide, chlorothiazide, hydrochlorothiazide, hydroflumethiazide, and trichloromethiazide), and other diuretics having a sulphonamide substituent in the benzene ring. Precolumn derivatization with sodium nitrite and N -(1-naphthyl)ethylenediamine, to form the coloured azo dyes of the hydrolyzed diuretics, decreased the polarity of the compounds and, consequently, their retention in the micellar eluents, and permitted detection in the visible region, eliminating thus the …

HYDROGELS OF HYALURONIC ACID AND alpha, beta-POLYASPARTYLHYDRAZIDE AND THEIR BIOMEDICAL AND PHARMACEUTICAL USES

2005

Compositions and products based on the chemical crosslinking of hyaluronic acid with a polyfunctional polymer having a protein-like structure, bearing hydrazido pendent groups along the polymeric chain. The polymer is preferably, alpha-beta-polyaspartylhydrazide, a biocompatible macromolecule. The materials obtained after crosslinking, specifically hydrogels, undergo a reduced chemical and enzymatic degradation, unlike the starting hyaluronic acid, and they can be used to prepare systems for applications in the biomedical and pharmaceutical field.

Triazole-Containing [FeFe] Hydrogenase Mimics: Synthesis and Electrocatalytic Behavior

2019

Through a Cu-catalyzed Huisgen cycloaddition between terminal alkynes and azides (CuAAC) reaction, azide [(μ-SCH2)2N(4-N3C6H4)Fe2(CO)6] has demonstrated to be a robust and versatile reagent able to...

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

2008

Selective Uptake of Cylindrical Poly(2-Oxazoline) Brush-AntiDEC205 Antibody-OVA Antigen Conjugates into DEC-Positive Dendritic Cells and Subsequent T…

2014

To achieve specific cell targeting by various receptors for oligosaccharides or antibodies, a carrier must not be taken up by any of the very many different cells and needs functional groups prone to clean conjugation chemistry to derive well-defined structures with a high biological specificity. A polymeric nanocarrier is presented that consists of a cylindrical brush polymer with poly-2-oxazoline side chains carrying an azide functional group on each of the many side chain ends. After click conjugation of dye and an anti-DEC205 antibody to the periphery of the cylindrical brush polymer, antibody-mediated specific binding and uptake into DEC205(+) -positive mouse bone marrow-derived dendri…

A novel high-spin heterometallic Ni12K4cluster incorporating large Ni–azide circles and an in situ cyanomethylated di-2-pyridyl ketone

2005

Reaction of di-2-pyridyl ketone (dpk) with nickel acetate and azide in the presence of potassium tert-butylate as a catalytic base generates the title compound, which contains the largest [Ni(m1,1-N3)]6 circles in the discrete ferromagnetically-coupled MII–azide cluster family, and shows an unprecedented in situ cyanomethylation of ketone. Clemente Juan, Juan Modesto, Juan.M.Clemente@uv.es

Automated simultaneous triple dissolution profiles of two drugs, sulphamethoxazole-trimethoprim and hydrochlorothiazide-captopril in solid oral dosag…

2003

This article deals with the simultaneous determination of three dissolution profiles with the aid of the new and emerging continuous-flow methodology known as multicommutation. This methodology is based on a flow network of a set of solenoid valves controlled by the computer and acting as independent multicommutators to allow the easy and automated control of flowing solutions. The obtained three dissolution profiles from one dosage form are the whole formulation profile or "global profile" recommended by pharmacopoeias, and, at same time, are recorded two "individual" profiles from two drugs present in the formulation. This is the second attempt to obtain simultaneously three dissolution p…