A validated enantioselective HPLC assay of dexibuprofen in dexibuprofen tablet formulations

A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated for the quantitation of dexibuprofen in dexibuprofen tablets using ovomucoid chiral stationary phase (Ultron ES-OVM). The mobile phasewas composed of 0.025 M potassium phosphate dibasic (pH 4.5)-methanol-ethanol (85:10:5 v/v/v). The method was validated for specificity, linearity, range, accuracy, precision and robustness. The method was enantiomerspecific for the determination of dexibuprofen [S-(+)-isomer ibuprofen] in the presence of R-(-)-isomer ibuprofen in bulk drug, pharmaceutical dosage form and under stress degradation. The method was linear over the range 15-35 mg/mL with r2 = 0.9995; accuracy and precision were acceptable with %RSD < 2.0%. The method was found to be specific, precise, accurate, robust and stability-indicating, and can be successfully applied for the routine analysis of dexibuprofen in bulk drug and pharmaceutical dosage form.     

Novel Method for Determination of Anthracene by Coupling Dispersive Liquid-Liquid Extraction to First-Derivative Synchronous Spectrofluorimetry

A novel method could be adopted successfully for determination of anthracene in environmental samples, utilizing dispersive liquid-liquid extraction followed by first-derivative synchronous fluorimetry at a constant wavelength difference Δλ?=?165 nm, where a linear calibration curve was obtained in a concentration range of 0.5–100 ng mL^?1 at 244 nm. The detection limit was 0.1 ng mL^?1. The method can be easily adopted for determination of anthracene in aqueous media including tap water and river water. The recoveries obtained were 85.40–108.02 %. The proposed method was validated according to International Conference of Harmonization (ICH) guide lines and successfully applied to determine anthracene in pure form and in water samples including real life water samples from different sources. All the results obtained were compared with those of published method, where no a significant difference was observed.     

Time dynamics in the point process modeling of seismicity of Aswan area (Egypt)

The seismicity observed in the Aswan area (Egypt) between 1986 and 2003 was deeply investigated by means of time-fractal methods. The time dynamics of the aftershock-depleted seismicity, investigated by means of the Allan Factor, reveals that the time-clustering behavior for events occurred at shallow depths (down to 12.5 km from the ground) as well as for events occurred at larger depths (from 15 km down to 27.5 km) does not depend on the ordering of the interevent times but mainly on the shape of the probability density functions of the interevent intervals. Moreover, deep seismicity is more compatible with a Poissonian dynamics than shallow seismicity that is definitely more super-Poissonian. Additionally, the set of shallow events shows a periodicity at about 402 days, which could be consistent with the cyclic loading/unloading operations of the Lake Naser Dam. Such findings contribute to better characterize the seismicity of the Aswan area, which is one of the most interesting water reservoirs in the world, featured by reservoir-induced earthquakes.     

Effects of exposure time on the anodic dissolution of Monel-400 in aerated stagnant sodium chloride solutions

The anodic dissolution of Monel-400 (63.0% Ni, 28–34% Cu) alloy after its immersion in freely aerated stagnant 3.5% NaCl solutions for 0, 24, and 72 h has been investigated. The study was carried out using a variety of electrochemical techniques and gravimetric measurements after varied exposure periods (5–160 days). The work was complemented by scanning electron microscopy and energy dispersive X-ray analyzer (SEM/EDX) investigations. The electrochemical measurements showed that Monel suffers both general and pitting corrosion. The severity of uniform corrosion decreased, while pitting one increased with increasing the immersion time to 24 h and further to 72 h before measurements. Gravimetric data indicated that the weight loss increased, while the corrosion rate decreased for Monel with time. SEM images and EDX profile analyses confirmed that the corrosion of Monel after 160 days immersion in NaCl solutions occurs due to the selective dissolution of nickel.     

Challenges in the electrochemical coating of high-strength steel screws by aluminum in an acidic ionic liquid composed of 1-Ethyl-3-methylimidazolium chloride and AlCl3

In this paper we show that screws made of high-strength steel (12.9 grade) can, in principle, be electrochemically coated with up to 40-μm-thick Al layers in an ionic liquid composed of 1-Ethyl-3-methylimidazolium chloride and AlCl₃ (40/60 mol%). The main challenge for the adhesive deposition of Al is a thorough purification and pretreatment of the screws prior to Al deposition. It is shown that a combination of degreasing, etching, plasma treatment, and electrochemical etching in the ionic liquid is a prerequisite for an adhesive and well protecting Al layer. Even then it can happen that at some sites Al does not adhere sufficiently well. A proper posttreatment is essential, too, and we show that the ionic liquid must be removed with another ionic liquid prior to a chemical passivation in boiling distilled water to get a high layer quality.     

Simulation of muon-induced air showers affecting CMS tracking detectors

We study the propagation of energetic muons produced by ultrahigh energy cosmic rays which could penetrate the cavern of a giant experiment called Compact Muon Solenoid (CMS) at CERN. The present work is based on our previous simulation model proposed in [1]. We have improved this model by (1) eliminating the ambiguity via adding Landau-Pomeranchuk-Migdal effect to the Monte-Carlo code, (2) using different incidence angles of the simulated air showers, (3) defining the actual contents of the CMS cavern concrete. We estimate the energy spectrum of muons produced by air showers of primary protons and photons, which could be detected as a background in the CMS tracking detectors. Our results show that muons produced by air showers within the energy range 10¹⁷–10²⁰ eV injected to the CMS site could penetrate the cavern with cutoff energy 36.5 GeV. The article is published in the original.     

ADDUCTS FROM 2, 3-DIARYL-5-PHENYLMETHYLENE-4-OXO-1, 3-THIAZOLIDINE-1-OXIDES

Abstract

5-Phenylrnethylene-2, 3-diaryl-4-oxo-1,3-thiazolidine-1-oxides 2 which synthesised via peracetic acid oxidation of the respective 1, 3-thiazolidines 1 reacted with benzylamine and Grignard reagents to afford the respective 5-α-substituted benzyl-2, 3-diaryl-4-oxo-1,3-thiazolidine-l-oxides 3 and 4. Structures of 3 and 4 were based on analytical and spectral evidence.     

Studies on heterocyclization of acetoacetanilide

Base-induced cyclocondensation of acetoacetanilide (1) and benzoyl isothiocyanate (2) afforded mercaptopyridine (4). Compound 4 reacted with NaOCl in presence of NH₄OH/NaOH to produce isothiazolopyridine (6). Heterocyclization of 4 by ethyl bromoacetate and/or phenacyl bromide afforded pyridothiazapene and pyridine derivatives 7, 8, respectively. The synthesis of pyrazolopyridine (9) was achieved by reaction of 4 with hydrazine hydrate. Oxidative cyclization of 4 by Br₂ produced isothiazolopyridine (10). Chlorination of compound 4 yielded isothiazolopyridine dioxide (11). Compound 1 transformed into pyrane derivatives 12 and 13 by reaction with benzylidenemalononitrile and benzylideneacetophenone, respectively. Heterocyclization of compound 1 by ethylcyanoacetate and diethyloxalate afforded pyridine and cyclopentane derivatives 14 and 15, respectively. Compound 1 heterocyclized to indenopyrane (16) or indenopyrrole (17) upon reacted with ninhydrin on cold and hot condition, respectively. Heterocyclization of compound 1 and benzilmonohydrazone afforded pyridazine derivative 18. Coupling of 1 with diazonium salt afforded hydrazone 19 which cyclized using CS₂/KOH gave pyridazine derivative 20.     

Anti-Microbial,Anti-Oxidant,and α-Amylase Inhibitory Activity of Traditionally-Used Medicinal Herbs: A Comparative Analyses of Pharmacology,and Phytoconstituents of Regional Halophytic Plants’ Diaspora

Halophytes are the category of plants growing under harsh conditions of super-salinity, and are wide-spread in the coastal Mediterranean climatic conditions and desert oasis. They are adept at surviving through maintaining excessive production of enzymatic, and non-enzymatic secondary metabolites, especially phenolics and flavonoids that primarily work as anti-oxidants and phytoalexins. Five major halophyte species growing in the kingdom’s Qassim’s high-salted desert regions were investigated for confirming their traditionally used biological activity of sugar-control and anti-infectious properties. In this context, the comparative presence of phenolics, and flavonoids together with anti-microbial, anti-oxidants, and the anti-diabetic potentials of the plants’ extracts were investigated through the α-amylase inhibition method. The highest concentrations of phenolics and flavonoids were detected in Salsola imbricata (360 mg/g of the extract as Gallic-Acid-Equivalents/GAE, and 70.5 mg/g of the extract as Rutin-Equivalents/RE). In contrast, the lowest concentrations of phenolics and flavonoids were detected in Salsola cyclophylla (126.6 mg/g GAE, and 20.5 mg/g RE). The halophytes were found rich in trace elements, a factor for water-retention in high-salinity plants, wherein iron and zinc elements were found comparatively in higher concentrations in Aeluropus lagopoides (4113 µg/kg, and 40.1 µg/kg, respectively), while the copper was detected in higher concentration (11.1 µg/kg) in S. imbricata, analyzed through Inductively Coupled Plasma Optical Emission Spectrometric (ICP-OES) analysis. The anti-oxidant potentials and α-amylase enzyme inhibition-based anti-diabetic activity of S. imbricata was significantly higher than the other halophytes under study, wherein S. cyclophylla exhibited the lowest level of α-amylase inhibition. The maximum DPPH radicals’ (52.47 mg/mL), and α-amylase inhibitions (IC₅₀ 22.98 µg/mL) were detected in A. lagopoides. The anti-microbial activity against the Methicillin-Resistant Staphylococcus aureus was strongly exhibited by Zygophyllum simplex (33 mm Inhibition Zone-Diameter, 50 µg/mL Minimum-Inhibitory-Concentration), while Escherichia coli, Enterococcus faecalis, and Candida albicans growths were moderately inhibited by Tamarix aphylla. The current findings exhibited significant differences among the locally distributed halophytic plants species with regards to their bioactivity levels, anti-oxidant potentials, and the presence of trace elements. The ongoing data corroborated the plants’ traditional uses in infections and diabetic conditions. The enhanced local distribution of the plants’ diaspora and higher density of occurrence of these plants species in this region, in comparison to their normal climatic condition’s counterparts, seemed to be affected by humans’ use of the species as part of the traditional and alternative medicine over a period of long time.