Three accurate, rapid and simple atomic absorption spectrometric, conductometric and colorimetric methods were developed for the determination of norfloxacin (NRF), ciprofloxacin (CIP), ofloxacin (OFL) and enrofloxacin (ENF). The proposed methods depend upon the reaction of ammonium reineckate with the studied drugs to form stable precipitate of ion-pair complexes, which was dissolved in aceton...

Objective: A simple, direct and accurate spectrophotometric method has been developed for the determination of glimepiride (GLM) in pure and pharmaceutical formulations by complex formation with bromocresol green (BCG). Methods: The method involves the formation of a yellow ion-pair complex between bromocresol green reagent with glimepiride (C24H34N4O5S); after reacted it with Na2CO3 to give C2...

Positive ion mode matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used to explore nonspecific interactions between proteins and oligonucleotides. The formation of noncovalent complexes showed correlation with the type of oligonucleotide bases and with the amino acid composition of the proteins. Among the four DNA homooligomers, abundant protein-nucleic acid complexe...

barrier to the permeation of most drugs, and especially as a hydrophobic barrier against hydrophilic drugs and ionized drugs. One possible means of facilitating the transdermal delivery of ionic drugs is through ion-pair formation. Oppositely charged ions can interact to form new species known as ion-pairs. This association reduces or neutralizes electrostatic charges and consequently reduces t...

Levofloxacin (LFX), an antimicrobial agent has been detected by using picric acid (PA) as an anionic reagent in aqueous medium. On mixing the reactants in distilled water yellow colored product is separated within two minutes which was found to be an ionassociation complex (LFX-PA) of both the reactants. Spectroscopic and voltammetric studies were carried out to explain the interaction between ...

Metal organic contacts are at the basis of devices such as organic light emitting diodes (OLEDs). Here, we report a theoretical investigation of the chemical interaction between a Mg atom and an organic film made of tris(8-hydroxyquinoline)aluminum (Alq3) molecules. The latter is modeled either by an isolated molecule or by a bulk crystal. Using first-principles molecular dynamics for structura...

The role of the anion on ionophore properties valinomycin was studied in a model floating bilayer lipid membrane (fBLM) using supporting electrolytes containing K+ with four different counter species (ClO4–, H2PO4–, Cl–, and F–). electrochemical impedance spectra indicate that resistance decreases decrease Gibbs free energy solvation. IR demonstrate does not readily bind to KH2PO4, KCl, KF elec...

The kinetics and mechanism of ligand substitution reactions of [Pt(SMC)Cl(2)] (SMC = S-methyl-l-cysteine) with biologically relevant ligands were studied as a function of chloride and nucleophile concentrations at pH 2.5 and 7.2. It was observed that the slope and intercept obtained from the linear dependence of the observed rate constant on the nucleophile concentration strongly depend on the ...

The ion-pair formation constant (K(MLA)(0) in mol(-1) dm(3)) for Li(B15C5)(+) with a picrate ion (Pic(-)) in water was determined by potentiometry with a K(+)-selective electrode at 25 degrees C and an ionic strength of 0, where B15C5 denotes benzo-15-crown-5 ether. Using the concentration equilibrium constants, K(MLA), estimated from this value, the extraction constants (mol(-2) dm(6) unit) of...

The complexation reactions between Cu2+, Pd2+ and Ni2+ metal ions with promethazine (PM) in water or DMF were studied by the spectrophotometric methods at [(15, 25,35 and 45±0.1) °C]. The complexation process was optimized in terms of pH, temperature and contact time. The stoichiometry of the complex was found to be 1:1 (metal ion/ligand). The formation constants of the resulting complexes were...