Stability study of parabens in pharmaceutical formulations containing Paracetamol or Carbocisteine by high-performance liquid chromtatography

A new, simple, specific, sensitive, rapid, accurate and precise RP-HPLC method was developed for the proportioning of the methylparaben and the propylparaben in pharmaceutical formulations as well as the phenol, which is their main degradation product. These parabens are widely used as preservatives in pharmaceutical and cosmetic products. The separation was performed on a C18-column using a mobile phase elution gradient (Acetate buffer 50mM pH 5/Acetonitrile). The detection was performed at a fixed wavelength (l = 271nm), with a flow rate of 1.3 ml/min. The detector response was linear in concentrations ranging from 10 to 60 μg/ml for the methylparaben, from 3 to 15 µg/ml for the propylparaben and from 0.125 to 2.5 µg/ml for the phenol. The intra and inter day variation was found to be less than 2%. The limits of quantification and of detection of the phenol are of 0.1 µg/ml and 0.03 µg/ml, respectively. The recovery ratio was equal to 101.8 % for the methylparaben, 101.2 % for the propylparaben and 98.4 % for the phenol. The proposed method was used to monitor the degradation of the parabens and the production of the phenol in studied solutions

2-Phenyl­thieno[2,3-b]quinoxaline

The title compound, C16H10N2S, is almost planar (r.m.s. deviation for all non-H atoms = 0.080 Å). The dihedral angle between the three fused-ring system and the phenyl ring is 9.26 (3)°. The S atom and the opposite C atom of the thio­phene ring are mutually disordered with an occupancy ratio of 0.7706 (19):0.2294 (19)

Quantitation of venom Antigens from Moroccan vipers in serum by using an Enzyme-Linked Immunosorbent Assay (ELISA) toward improving health vigilance systems

In the present study an ELISA assay was developed and validated for detection and determination of the concentration of snakes venom in biological samples. Individual component of each venom (Cerastes cerastes and Macrovipera mauretanica) used as immunogen to raise specific rabbit IgGs in order to set up a sandwich-type ELISA. Lower detection limit, linearity, accuracy, precision, reproducibility, and reference intervals were determined. The method proved to be simple, specific, reproducible, sensitive (detection limit = 0.5 ng/ml) and the calibration plot was based on linear regression analysis (r = 0.980) between 0.9 and 1000 ng/mL of venom concentration, with a lower limit of quantification of 1.58 ng/mL. The intra- and interassay coefficient of variation ranged from 2,02 to 4.62% and 5.29 to 7.40%, respectively. The specificity of the assay was tested using vipers, cobra and scorpion venom. This method detected venom from all viper species tested without significant cross reactivity with other venoms in the concentration range of 0.9–1000 ng/mL. This ELISA described is sufficiently validated for clinical evaluation. The method is adaptable to other venoms. This is potentially useful for clinical diagnosis of snakebite, to monitor antivenom dose, and consequently to improve the national health monitoring systems

Development of stability indicating method for quality assessment of African Albendazole tablets

In order to assess the quality of Albendazole tablets (Alb) sampled in three countries from West Africa, several physical and chemical tests were performed on tablets at normal conditions. A simple and economic HPLC method has been developed, validated and used for the simultaneous determination of Albendazole (Alb) content, as well as its impurities and the uniformity of its content. The stability-indicating HPLC method was performed on a Symmetry C18-5µm 250 mm × 4.6 mm column with a gradient elution using a mobile phase composed of acetonitrile and sodium acetate buffer. The flow rate was set at 1 mL.min−1 and the eluent was monitored at 295nm. The method was validated for specificity, linearity, accuracy, precision, robustness and detection and quantification limits, in accordance with International Conference on Harmonisation Quality 2 (ICH Q2) guidelines. This method was performed on different Alb samples (originals and generics) products collected from Senegal, Niger and Mali. The obtained results showed that, the contents of the generic tablets from Niger and Mali comply with the United States Pharmacopeia (USP) monograph acceptance criteria. However, more than 20% of the generic tablets don’t meet the USP monograph impurity limits. In conclusion, the described analytical method is simple, sensitive and accurate. Thus, it could be useful for manufacturing and quality control assays

The role of scientific research on nuclear radiation waste management and preserving environment

On the level of this article, we deal with nuclear radiation (and their residues), which is defined as a physical phenomenon and strong atomic activity that occurs in unstable atoms of elements. We are interested in studying radiation as the emission or diffusion of energy into space in the form of electromagnetic waves or particles. The scientist Fermi (1934 AD) is among the first to present scientific research in this field. Radioisotopes are considered one of the most prominent discoveries of modern science and based on the importance of the topic, scientists and researchers searched for methods and techniques to facilitate the implementation of practical applications for radiation measurement, and among those methods a specialized program was used to simulate radiation dose (digital simulation in a computer through the use of an imaginary model of the radiometric process with technology Monte Carlo using code (Geant 4). We have also highlighted the views of researchers and specialists in the area of disposal of radioactive waste, relying on a field study and a comparison of some of the currently adopted techniques to get rid of the negative consequences that each unreasonable (reckless) management and measure of this radioactive waste may have Among the most prominent results we have reached is highlighting the weakness of dealing with this topic and not giving it the right to research and scientific achievements carried out by researchers, which increases the complexity of the situation and from which it is difficult to control the problem in the future

Synthesis, Characterizations, and Quantum Chemical Investigations on Imidazo[1,2- a ]pyrimidine-Schiff Base Derivative: ( E )-2-Phenyl- N -(thiophen-2-ylmethylene)imidazo[1,2- a ]pyrimidin-3-amine

International audienc

Determination of correction factor of self-absorption for lead-210 in environment samples using spike method

In environment radiation measurement, calculation the correction factors are critical, especially for low energy measurement because of self-absorption phenomena. In this work the main purpose is to determination the self-absorption correction factors of lead-210 (210Pb) energy (46.5keV) in various environment samples (7 sediments, 5 soil) using an experimental method called Spike Method. The samples were collecting from different places in Syrian. They were prepared according to the laboratory producers starting from collecting, cleaning, drying, grounding, hemogenic and calculating the appearance density. Low-energy gamma spectroscopy HPGe was used for radiation analysis which available at the laboratories of the Protection and Safety Department - Syrian Atomic Energy Commission – Syria. The spike method depends on adding a quantity of a standard solution with a known activity which contains lead isotope 210Pb and added to the studied samples. Self-absorption correction factors (CF) calculated by the ratio of the count rate or activity of spiked and unspiked samples. The CF for sediment samples were between 29% to 54% and for soil samples, the CFs were between 38% to 56% recording correction higher than sediment samples. The results showed a relatively high self-absorption and CFs values because of the chemical composition changeable between the spiked and unspiked samples. For that, it is better to adopt other methods less expensive, give results faster, higher accuracy and do not make change in the chemical composition. The results were also showed the density factor is the most influential factor in self-absorption phenomena

Synthesis, Characterizations, and Quantum Chemical Investigations on Imidazo[1,2‑<i>a</i>]pyrimidine-Schiff Base Derivative: (<i>E</i>)‑2-Phenyl‑<i>N</i>‑(thiophen-2-ylmethylene)imidazo[1,2‑<i>a</i>]pyrimidin-3-amine

In this study, (E)-2-phenyl-N-(thiophen-2-ylmethylene)­imidazo­[1,2-a]­pyrimidin-3-amine (3) is synthesized, and detailed spectral characterizations using 1H NMR, 13C NMR, mass, and Fourier transform infrared (FT-IR) spectroscopy were performed. The optimized geometry was computed using the density functional theory method at the B3LYP/6-311++G­(d,p) basis set. The theoretical FT-IR and NMR (1H and 13C) analysis are agreed to validate the structural assignment made for (3). Frontier molecular orbitals, molecular electrostatic potential, Mulliken atomic charge, electron localization function, localized orbital locator, natural bond orbital, nonlinear optical, Fukui functions, and quantum theory of atoms in molecules analyses are undertaken and meticulously interpreted, providing profound insights into the molecular nature and behaviors. In addition, ADMET and drug-likeness studies were carried out and investigated. Furthermore, molecular docking and molecular dynamics simulations have been studied, indicating that this is an ideal molecule to develop as a potential vascular endothelial growth factor receptor-2 inhibitor