Three sensitive, selective, rapid and easily reproducible spectrophotometric methods (A-C) have been developed for the determination of propranolol hydrochloride (PPH) as a hydrochloride free base propranolol (PPL) in bulk sample and in its dosage forms. These methods are based on ion-pair formation between propranolol as a hydrochloride and free base and three acidic (sulphonphthalein) dyes; n...

Purpose: To develop a new and fully validated ion-pair spectrophotometric method for the determination of duloxetine hydrochloride (DX). Methods: Ion-pair spectrophotometric method was employed for the determination of duloxetine hydrochloride (DX) in bulk and pharmaceutical formulations using acidic dye methyl orange (MO) as ion-pairing agent at pH 4 (phthalate buffer). The yellow ion-pair com...

The hydrolysis of amino acid derivatives catalyzed by papain (EC 3.4.4.10) proceeds through the formation of an acyl-thiolenzyme intermediate (cf. refs. [ 1,2] ). The pH-rate profde of the formation of this intermediate displays a bell-shaped curve depending on the ionization of two groups with pK, values of about 4 and 8 [ 1,2]. In the light of the steric structure of the active site of papain...

A silver-acrylate nanocomposite was prepared using a novel one-pot strategy involving eosin dye as visible sensitizer and an amine derivative as radicals source. The mechanism highlighted by steady state photolysis and time resolved absorption spectroscopy lies on the initial formation of a strong ion pair complex between eosin and Ag + . Upon visible irradiation, the excited triplet state of t...

in this study, a sensitive method of dispersive liquid phase microextraction based on ion-pair combined with the flame atomic absorption spectrometry was proposed for the determination of trace ni(ii) using aliquat 336-chloride as ion pair agent. several factors which have effect on  the microextraction efficiency of ni(ii), such as ph, extraction and dispersive solvent type and their volume, c...

The kinetics of the energy dissipation pathways of the excited ion pairs formed upon light absorption of the hydrogen bonded complex between N-methyl-3-hydroxynaphthalimide (3HONI) and 1-methyl-imidazole (MIm) has been studied in a wide temperature range in solvents of various polarities. In polar media such as butyronitrile, three emitting species are found which are assigned as hydrogen bonde...

In this study, a fast and simple spectrophotometric method was developed for the determination of amoxicillin in drugs without any extraction steps. The is based on formation colored ion pair complex between bromocresol green amoxycillin dimethyl sulfoxide-acetonitrile (50 % v/v) medium. absorbance bluish measured at wavelength 630 nm. factors that affect formation, such as time, reagent concen...

To explore how the ion-pair in a single salt molecule evolves with the addition of water, infrared (IR) spectra of complexes composed of NaCl and multiple water molecules have been recorded for the first time. The NaCl(H2O)n complexes were formed and probed in liquid helium nanodroplets, and IR spectra were recorded for n = 1 → 4. The spectra for n = 1, 2, and 3 are consistent with formation of...