Synthesis and spectral characterization of CoxMg1-xAl2O4 as new nano-coloring agent of ceramic pigment.

New nano-blue ceramic pigments of Co(x)Mg(1-x)Al(2)O(4) (0< or =x< or =0.1) have been prepared by co-precipitate-combustion as a hybrid method using urea as a fuel at 500 degrees C in open furnace in air atmosphere. The structure of pigment is assigned based on TGA/DTA/DrTGA analyses, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Also, electronic spectra, infrared (IR) and diffuse reflectance spectroscopy (DRS) using CIE L*a*b* parameter measurement techniques were used. The results revealed that the nano-particle size of pigments were obtained in the range 30-38 nm as well as the varying colors and particle size as a result of different calcinations temperatures within the range of 500-1200 degrees C for 2h.

Spectrophotometric microdetermination of nefopam, mebevrine and phenylpropanolamine hydrochloride in pharmaceutical formulations using alizarins.

Simple and rapid spectrophotometric procedures have been established for quantitation of nefopam hydrochloride (NF) mebevrine hydrochloride (MB) and phenylpropanolamine hydrochloride (PP). The procedures are based on the reaction between the examined drugs (NF, MB and PP) and alizarin (I), alizarin red S (II), alizarin yellow G (III) and quinalizarin (IV) producing ion-pair complexes which can be measured at the optimum wavelength. The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 0.5-30.0 microg ml(-1). The molar absorptivity, Sandell sensitivity, detection and quantification limits are also calculated. The correlation coefficient was > or =0.9988 (n=6) with a relative standard deviation (R.S.D.) of < or =1.3, for six determinations of 20 microg ml(-1). The methods are successfully applied to the determination of NF, MB and PP in their pharmaceutical formulations.

Spectrophotometric determination of phenylephrine HCl and orphenadrine citrate in pure and in dosage forms.

A simple and rapid spectrophotometric methods have been estimated for the microdetermination of phenylephrine HCl (I) and orphenadrine citrate (II). The proposed methods are based on the formation of ion-pair complexes between the examined drugs with alizarine (Aliz), alizarine red S (ARS), alizarine yellow G (AYG) or quinalizarine (Qaliz), which can be measured at the optimum lambda(max). The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 2-36 microgram ml(-1), whereas optimum concentration as adopted from Ringbom plots was 3.5-33 microgram ml(-1). The molar absorptivity, Sandell sensitivity, and detection limit are also calculated. The correlation coefficient was >/=0.9988 (n=6) with a relative standard deviation of

Determination of the thermodynamic parameters and stability constants of UO2(2+), Th4+, and Ce3+ complexes with some azo-benzene-N-malonic acid derivatives.

Proton-ligand dissociation and metal-ligand formation constants of azobenzene-N-malonic acid (I), p-Cl-azobenzene-N-malonic acid (II), p-Br-azobenzene-N-malonic acid (III) and p-COOH- azobenzene-N-malonic acid (IV) with UO2(2+), Th4+ and Ce3+ were evaluated potentiometrically using Bjerrum's method at 25, 35 and 45 +/- 0.5 degrees C and ionic strength 0.1 M in 40% v/v ethanol-water medium. The order of stability constants was found to be Ce3+ > Th4+ > UO2(2+). The effect of temperature on the dissociation and stability constants of the formed complexes was studied and the corresponding thermodynamic functions were derived and discussed. The ratio of metal-ligand was determined conductometrically. The structure of the ligands under investigation as well as their metal complexes has been elucidated by elemental analysis, IR and 1HNMR spectroscopy.