Iranian Journal of Analytical Chemistry
Volume:2 Issue: 2, Summer and Autumn 2015

In this work, a procedure for preconcentration of silver using dispersive liquid–liquid microextraction with the reagent dithizone as complexing reagent was developed. At pH 2, silver ions are complexed with dithizone and extracted into the fine droplets formed when mixing carbon tetrachloride (extraction solvent), ethanol (disperser solvent) and the sample solution. After extraction, the phases are separated by centrifugation and silver is determined in the enriched phase by FAAS. After extraction, the enrichment factor was 73.21. The detection limit of the method was 30.4 ng mL-1 and the relative standard deviation for ten determinations of 0.1 µg mL-1 silver was 3.19 %. The results for the determination of silver in environmental water samples (tap water, well water, mineral water), tea and pepperbrush have demonstrated the applicability of the proposed method.

The Quantitative Structure–Activity Relationship of a series of novel Thiazoline derivatives with anticancer activity has been studied by using the density functional theory by B3LYP/ 6-31G. Descriptors of quantum mechanics of 21 thiazoline derivatives with known activity were obtained. Multiple linear regressions were employed to model the relationships between molecular descriptors and biological activity of molecules using stepwise method. The most model shows not only significant statistical quality, but also predictive ability, with the square of adjusted correlation coefficient (R2=0.945) and standard error (SE=0.586). We find that the anticancer activity expressed that as half maximal inhibitory concentration (IC50), closely relates to the highest occupied molecular orbital, dipole moment, softness, hardness, ionization energy, electron affinity. Accordingly can be offered a quantitative model, and interpret the activity of the compounds relying on the multivariate statistical analysis. This study shows that the prediction results were in excellent agreement with the experimental value.  The results can offer some useful references for understanding the action mechanism and designing new compounds with anticancer activity.

Benign Prostatic Hyperplasia generally affects males above fourty years of age and has significant effect in overall quality of life (QOL). This is one of the cause of millions of dollors in healthcare expenditure. Alpha one adrenoreceptor blockers are frequently used for the benign prostatic enlargement because of their significant effect on storage and voiding symptoms, QOL, flow rate and post void residual urine volume. The present study is review on the determination of three alpha one adrenoreceptor blockers Alfuzosin, Silodosin and Naftopidil in various matrices and combinations. This kind of literature is helpful for those scientists engaged in the determination of these drugs by supporting them in terms of current available literature is one platform so that they can decide the initial conditions of their research such as decisions of mobile phase, dilutions etc. This review article also helps scientists engaged in developing formulations of these drugs.

In the present study, silver oxyfluoride modified silver electrode was employed to electrocatalytic oxidation of isoniazid. The process of oxidation and its kinetics were established by using cyclic voltammetry, chronoamperometry and amperometry techniques. The modified electrode shows a stable and linear response in the concentration range of 3×10−4 to 2.1×10−3 mol L-1 with a correlation coefficient of 0.9953. The overall number of electrons involved in the catalytic oxidation of isoniazid was found 4 electrons. The diffusion coefficient of 3.11×10−5 cm2 s-1 for isoniazid was also estimated using chronoamperometry study. It has been shown that using the silver oxyfluoride modified silver electrode, isoniazid can be determined by amperometry method with limit of detection of 3.85 µmol L–1. The method was successfully applied for analysis of isoniazid in solid pharmaceutical formulations. The results of the analysis suggest that the proposed method has promise for the routine determination of isoniazid in the products examined.

Recent studies have reported that metal sulfide nanoparticles had potential adverse effects.  In this research, lead (II) sulfide nanoparticles have been synthesized under different reaction conditions. Scanning electron microscopy and X-ray diffraction were used to characterize the particle size and morphology. Distribution, accumulation and toxic effects of nanoparticles on rats as a biological model were studied.  Lead (II) sulfide nanoparticles (less than 50 nm in diameter) were administered orally in two doses (15 or 60 mg/Kg body weight/day) to Wister rats for 28 consecutive days. Lead concentrations and iron parameters in soft tissues were measured using inductively coupled plasma optical emission spectroscopy. The lead levels were highest in the liver, followed in decreasing order by the levels in the spleen, kidney and brain. There were no significant levels of lead in kidney and brain at low dose of administration. Iron concentration was lowest in the group that had the highest lead level, which is probably due to an interference that could take place by lead through iron uptake mechanism.

A rapid, specific and accurate proton quantitative Nuclear Magnetic Resonance spectroscopic (1H qNMR) and also a reversed phase derivatization HPLC method have been developed to quantify a toxic, UV-visible inactive and non-volatile impurity N,N-Dimethylamine hydrochloride (DMA∙HCl) in Metformin Hydrochloride (MF∙HCl), an Active Pharmaceutical Ingradient. The method is based on proton quantitative NMR spectroscopy (1H qNMR) using Glycine as internal standard and deuterium oxide (D2O) as diluent. Both the methods have been validated as per the parameters of ICH guidelines and are found to be comparable.The advantages of the proposed 1H qNMR method are that no certified reference standard of DMA∙HCl is required for quantification, the method is specific, non-destructive and can be applied for quantification of DMA∙HCl in process, quality control for the manufacturing of Metformin hydrochloride as well as commercial dosage form products.

A simple, sensitive, accurate and precise simultaneous UV spectrophotometric method has been developed for the estimation of Carisoprodol, Paracetamol and Caffeine in tablet dosage form. The absorption maxima of the drugs were found to be 221, 248 and 273 nm for Carisoprodol, Paracetamol and Caffeine respectively, in methanol, using a double beam UV/Visible Spectrophotometer. Carisoprodol, Paracetamol and Caffeine obeyed Beer’s law in the concentration range of 0.4-2 μg/mL, 2-10 μg/mL and 2-10 μg/mL, respectively. The correlation coefficient was found to be 0.9922, 0.9917 and 0.9943 for Carisoprodol, Paracetamol and Caffeine, respectively. The method was validated for various parameters according to International Conference on Harmonization guidelines. The low relative standard deviation values indicate a good precision and high recovery values indicate the accuracy of the proposed method.

Hydrous manganese dioxide nanoclusters are prepared by the oxidation of manganese (II) ions with ammonium persulfate and used as a new sorbent for Ag+ ion removal from aqueous medium. The synthesized compound is characterized using scanning electron microscopy, dynamic light scattering, energy dispersive analysis of X-rays, X-ray diffraction and BET surface measurements. Scanning electron microscopy images showed that the synthesized Hydrous manganese dioxide nanoclusters include cactus-shaped nanoclusters with uniform needles of average diameter of 36 nm and length of 1000 nm. X-ray diffraction data reveal that γ-MnO2 is formed in this method. Batch experiments are carried out to evaluate the Ag+ adsorption capacity of Hydrous manganese dioxide nanoclusters. The maximum adsorption capacity estimated by the Langmuir model was 81.97  mg g-1 for Ag+. Silver ion adsorption on Hydrous manganese dioxide nanoclusters is a fast process and the kinetics followed a pseudo-second-order rate equation. The removal efficiency of Ag+ depends on Hydrous manganese dioxide nanoclusters amount, pH and temperature of the solution. The presences of Na+, Ca2+ and Mg2+ ions in the concentrations lower than 200 ppm have no significant influence on silver ion removal. The adsorbed ions can easily eluted by the small volume of a solution consisting thiourea and hydrochloric acid. Finally, the experimental data show that the synthesized Hydrous manganese dioxide nanoclusters can quantitatively remove silver ions from real water samples.