Hamada M. Killa

Three Spectrophotometric Methods for the Determination of Oxomemazine Hydrochloride in Bulk and in Pharmaceutical Formulations Using Bromocresol Green, Congo Red, and Methyl Orange

Abstract Three simple, sensitive, and highly accurate spectrophotometric methods have been developed for the determination of oxomemazine hydrochloride (OXO‐HCl) in bulk and in pharmaceutical formulations. These methods are based on the formation of yellow ion‐pair complexes between the examined drug and bromocresol green (BCG), congo red (CR), and methyl orange (MO) as reagents in universal buffer solution of pH 3.0, 5.5, and 3.5, respectively. The formed complexes were extracted with chloroform and measured at 413, 495, and 484 nm, respectively for the three systems. The best conditions of the reaction were studied and optimized. Beers law was obeyed in the concentration ranges 2.0–18.0, 2.0–14.0, and 2.0–16.0 µg ml−1 with molar absorptivity of 4.1×104, 1.1×104, and 3.5×104 mol−1cm−1, for the BCG, CR, and MO methods, respectively. Sandells sensitivity, correlation coefficient, detection, and quantification limits are also calculated. The proposed methods have been applied successfully for the analysis of the drug in pure and in its dosage forms. No interference was observed from common pharmaceutical excipients and additives. Statistical comparison of the results with those obtained by HPLC method shows excellent agreement and indicates no significant difference in accuracy and precision.

A study of mixed ligand complexes using differential pulse polarography

Abstract Differential pulse polarography was used to study the mixed ligand complexes of trimethylenediamine (TMDA) and oxalate (OX) with Cd(II) at constant ionic strength (μ = 1, NaNO 3 ) at 25°C. It has been found that the reduction of complexes is reversible and diffusion-controlled. Three mixed complexes, [Cd(TMDA)(OX)], [Cd(TMDA)(OX) 2 ] 2− and [Cd(TMDA) 2 (OX)], are formed. Their overall stability constants are: log β 11 = 6.78, log β 12 = 7.53 and log β 21 = 8.20, respectively.

Selective potentiometric method for determination of flucloxacillin antibiotic

Abstract A new and rapid potentiometric method for determination of flucloxacillin is developed. The method involves development of a flucloxacillin sensor with a membrane consisting of Aliquat 336S-flucloxacillin as an electroactive material in poly vinyl chloride matrix membrane plasticized with orthonitrophenyl-octylether or dioctylphthalate. The sensor shows fast, stable and reproducible response over the concentration range of 1.0 × 10−5–1.0 × 10−2 M flucloxacillin with anionic slopes of 60.7 ± 0.3 and 61.2 ± 0.2 and pH ranges of 6–11 and 7–11 for o-nitrophenyloctylether (o-NPOE) and dioctylphthalate (DOP) plasticized based membrane sensors, respectively. The response time of the sensor is stable and fast (7 s). The sensor exhibits high selectivity towards flucloxacillin in presence of amoxicillin, ampicillin, dicluxacillin, pencillin, many anions and drug excipients and diluents. Validation of the method according to the quality assurance standards shows suitability of the proposed sensors for use in the quality control assessment of the drug. Results with average recoveries of 99.6% and 99.7% and mean standard deviations of ±1.2% and ±1.5% for o-NPOE and DOP plasticized based membrane sensors, respectively, of the nominal are obtained which compare fairly well with data obtained using the British Pharmacopoeia method.

Electrochemical studies on simple and mixed ligand complexes using a hanging mercury drop electrode for stationary electrode voltammetry

A hanging mercury drop electode (HMDE) was used to study the simple and mixed ligand complexes of 1,3-diaminopropane (DAMP) and malonate (Mal) with cadmium(II) at constant ionic strength (μ = 1.0 M, NaNO3) and 25°C, using linear-scan and cyclic modes. The reduction of the simple and mixed complexes is reversible and diffusion controlled. The composition and stability constants of simple and mixed species have been studied, as well as the mixing constants for the mixed complexes. The overall formation constants of the mixed species were calculated statistically using the Watters and DeWitt method and compared with the observed values. The equilibria between the various mixed ligand complexes in solution and their equilibrium are also given.

Synthesis and Characterization of Coordination Behavior of Diclofenac Sodium Drug Toward Hg(II), Pb(II), and Sn(II) Metal Ions: Chelation Effect on Their Thermal Stability and Biological Activity

Diclofenac sodium compound has great biological, medical, industrial, and coordination applications. Most of its metal complexes have antibacterial and antifungal effects. A general survey of previous literature concerning the interaction of transition metals with diclofenac compound was given. From this survey, it is appeared that deep chemical studies were needed to through lighter on the complexing ability and chemical properties, due to presence of active groups such as amino, hydroxyl, carbonyl, and carboxyl groups. Therefore the present work was aimed mainly to study the spectroscopic, stability, and related thermodynamic parameters, structural, thermal, molar conductivity, and biological properties of the diclofenac sodium with selected metal ions such as Hg(II), Pb(II), and Sn(II). The used of theoretical concepts and experimental techniques were discussed. Solid complexes have been prepared and characterized by IR, UV-Vis, elemental analysis CHN, and 1H-NMR. Diclofenac reacts with Hg(II), Pb(II), and Sn(II) by molar ratio (2:1) (diclofenac:metal ion). IR, UV-Vis, spectra indicate that diclofenac behaves as a monobasic bidentate ligand coordinated to the metal ions via the deprotonated carboxylate O and carbonyl groups. The Hg(II), Pb(II), and Sn(II) complexes of diclofenac are found to have high activity against bacteria, especially Bacillus subtilis, and fungi, especially Aspergillus niger, whereas the Pb(II) complex is more active than the Sn(II) and Hg(II) complexes.

Mixed ligand complexes of copper with amino-acids and tartrate using differential pulse polarography. Part I

SummaryThe differential pulse (d.p.) polarography technique was used to study simple and mixed ligand complexes of copper(II) with tartrate anions and amino-acids (threonine, valine and isoleucine). The reduction of simple and mixed complexes was reversible and diffusion controlled, one mixed complex being formed in each case. The formation constants of simple and mixed complexes have been calculated. The mixing constants of ternary systems as well as the stabilization constants were also calculated. The formation constants of the ternary complexes were calculated statistically and compared with the observed values.

Electronic absorption spectra of some azo compounds with condensed ring systems in non-aqueous and mixed buffer solvents

Abstract The electronic absorption spectra of eight substituted phenylazo derivatives of α-and β-naphthol, 9-phenanthrol and 5- and 6-chrysenol were studied in different organic solvents. The assignment of the spectral bands obtained and also the effect of organic solvents on the colour of the compounds was investigated. The spectra in buffer solution over the pH range 2–14 were recorded and explained; also the pKa values were determined.

Studies on Mixed Complexes of Cd(II) With Trimethylenediamine and Succinate Using Differential Pulse Polarography

Abstract Ternary compleres of cadmium (II) with succinate (Succ) as primary ligand and trimethylenediamine (TMDA) as secondary ligand have been studied using differential pulse polarography. Schaap and McMasters treatment reveals the presence of three mixed complexes with stoichiometries 1:1:1, 1:1:2 and 1:2:1. The reduction is reversible and diffusion-controlled. The stability constants of mixed ligand complexes were calculated atatistically using watters method and compared with the observed values.

Differential pulse Polarographic study of simple and mixed ligand complexes of cadmium(II) with some dicarboxylate anions and imidazole

SummaryThe composition and stability of binary and ternary complexes of Cd(II) with phthalate and adipate anions as primary ligands and imidazole as a secondary ligand have been investigated using differential pulse d.p. polarography. The formation constants of simple mixed species have been calculated, as well as the mixing and stabilization constants. The overall formation constants of the mixed species are correlated and discussed in terms of statistical consideration and charge neutralization. The equilibria between the various mixed-ligand species in solution and their equilibrium are also given.

Electrochemical Behaviour of Some Azo Compounds of 4-Aminoantipyrine Derivatives Using Cyclic Voltammetry and DC Polarography Techniques

Abstract The electrochemical behaviour of some azo compounds of 4-aminoanti-pyrine derivatives (I-V) have been studied in ethanolic buffered solutions using tost polarography (DC sampled mode), linear sweep and cyclic voltam-mograms. Generally, the reduction polarograms of these compounds show a single, 4-electrons diffusion controlled irreversible wave within the entire pH range (2–12), which represents the reduction process. The kinetic parameters of the elctrode reaction are given.