Quantitative analysis of the cholesterol-lowering drugs ezetimibe and simvastatin in pure powder, binary mixtures, and a combined dosage form by spectrophotometry, chemometry, and high-performance column liquid chromatography

Simple, accurate, sensitive, and precise UV spectrophotometric, chemometric, and HPLC methods were developed for simultaneous determination of a two-component drug mixture of ezetimibe (EZ) and simvastatin (SM) in laboratory-prepared mixtures and a combined tablet dosage form. Four spectrophotometric methods were developed, namely, ratio spectra derivative, ratio subtraction, isosbestic point, and mean centering of ratio spectra. The developed chemometric-assisted spectrophotometric method was the concentration residual augmented classical least-squares method; its prediction ability was assessed and compared to the conventional partial least-squares method. The developed HPLC method used an RP ZORBAX C18 column (5 microm particle size, 250 x 4.6 mm id) with isocratic elution. The mobile phase was acetonitrile-pH 3.5 phosphate buffer (40 + 60, v/v) at a flow rate of 1.0 mL/min, with UV detection at 230 nm. The accuracy, precision, and linearity ranges of the developed methods were determined. The developed methods were successfully applied for determination of EZ and SM in bulk powder, laboratory-prepared mixtures, and a combined dosage form. The results obtained were compared statistically with each other and to those of a reported HPLC method; there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.     

INAA laboratory results evaluation of inter-laboratory analysis test

Participation in inter-comparison programs is an important process to enhance the accuracy and precision of the analytical techniques. The Instrumental Neutron Activation Analysis laboratory (INAA) at Egypt Second Research Reactor (ETRR-2), ETRR-2 INAA Laboratory, was participated in three inter-comparison tests organized by AFRA Research Reactor Project for Socio-economic development. AFRAIV-12 Inter-laboratory Analysis Test 2007 is the third inter-laboratory analysis test within that project. The laboratories were asked to analyze for 43 essential and toxic elements using nuclear and related analytical techniques, with neutron activation analysis as the common technique. Five materials were distributed to the participants representing foodstuff, medicinal plants and aquatic biomonitors according to the focus of the AFRA IV-12 2006–2010 project. In this paper the ETRR-2 INAA Laboratory results is evaluated.     

On the explicit solutions of forms of the Sylvester and the Yakubovich matrix equations

In this paper, we consider the explicit solutions of two matrix equations, namely, the Yakubovich matrix equation V−AVF=BW and Sylvester matrix equations AV−EVF=BW,AV+BW=EVF and AV−VF=BW. For this purpose, we make use of Kronecker map and Sylvester sum as well as the concept of coefficients of characteristic polynomial of the matrix A. Some lemmas and theorems are stated and proved where explicit and parametric solutions are obtained. The proposed methods are illustrated by numerical examples. The results obtained show that the methods are very neat and efficient.     

A new kaempferol trioside from <Emphasis Type="Italic">Farsetia aegyptia</Emphasis>

A new kaempferol trioside, kaempferol-3-O-(2″-α-L-arabinopyranosyl)-α-L-rhamnopyranoside-7-O-α-L-rhamnopyranoside, along with eight known flavonoid compounds were isolated from the methanolic extract of Farsetia aegyptia Turra. growing in Egypt. The structures were established on the basis of detailed spectral analysis (UV, ¹H NMR, ¹³C NMR, APT, HMBC, FABMS, and EIMS).     

Synthesis and anticancer activity of some new pyridine derivatives

Different substituents were introduced in positions 2 and 6 of 2,6 diaminopyridine in order to obtain new heterocyclic compounds. A new series of aza pyridine, imidazopyridine, benzodiazepine, indole, pyrimidine, and benzimidazole heterocyclic derivatives were synthesized in good yields. The anticancer activities of some of the new compounds were evaluated against liver cancer cell line HEPG2. Compounds 3, 4, 10, 11, 12, and 17 showed the highest activity when compared to 5-flurouracil (5-FU) and doxorubicin (DOX) chemotherapy.     

Study of optical properties of highly oriented nanocrystalline V2O5·nH2O films doped with K ions

Optical transmission and reflection measurements of highly oriented nanocrystalline K_xV₂O₅·nH₂O films (0 ≤ x < 0.01) were studied. The optical constants such as, refractive index, the extinction coefficient, absorption coefficient, optical band gap have been calculated. The optical spectra of all samples exhibited two distinct regions of optical gap, E_op1 suggesting a direct allowed transition with optical gap ranging from 0.37 up to 0.42 eV and E_op2 suggesting a direct forbidden transition with optical gap ranging from 2.02 up to 2.23 eV. This indicates that K_xV₂O₅·nH₂O films have more than one type of conduction mechanism.     

Transient absorption induced by a picosecond electron pulse in the fused silica windows of an optical cell

The transient absorption induced by picosecond pulse radiolysis in the windows of a fused silica optical cell is investigated with pump probe techniques in the UV and the visible range. After excitation with an electron pulse of 7 MeV and an effective duration of around 10 ps the absorbance changes during relaxation are recorded up to nanoseconds with a supercontinuum and a single wavelength probe at 263 nm. The complex spectral signatures and kinetics of the empty cell are set into relation with the transient absorption of water radiolysis. Special care is taken to assure equal irradiation conditions for the comparative measurements over the large spectral range. The results reveal clearly that the transient absorption induced in the fused silica cell is not negligible. The transient signals due to the cell should be considered in picosecond pulse radiolysis of solutions in order to avoid important errors on the time dependent yield of transient species, particularly of those absorbing in the UV.     

Synthesis, tautomeric structure and antimicrobial activity of 3-arylhydrazono-4-phenyl-[1,2,4]-triazepino[2,3-a]quinazoline-2,7(1H)-diones

A simple strategy for the synthesis of the hitherto unreported 3-arylazo-4-phenyl-[1,2,4]triazepino[2,3-H]quinazoline-2,7(1H)-diones is described. Spectral data indicated that the studied compounds exist predominantly in the hydrazone tautomeric form. The antimicrobial activity of the newly synthesized compounds was also evaluated. The results indicated that some of these compounds have moderate activity towards bacteria.     

Effects of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal injuries in Sprague-Dawley rats

Current anti-gastric ulcer agents have side effects, despite the progression and expansion of advances in treatment. This study aimed to investigate the gastroprotective mechanisms of Pithecellobium jiringa ethanol extract against ethanol-induced gastric mucosal ulcers in rats. For this purpose, Sprague Dawley rats were randomly divided into five groups: Group 1 (normal control) rats were orally administered with vehicle (carboxymethyl cellulose), Group 2 (ulcer control) rats were also orally administered with vehicle. Group 3 (positive control) rats were orally administered with 20 mg/kg omeprazole, Groups 4 and 5 (experimental groups) received ethanol extract of Pithecellobium jiringa ethanol extract at a concentration of 250 and 500 mg/kg, respectively. Sixty minutes later, vehicle was given orally to the normal control group, and absolute ethanol was given orally to the ulcer control, positive control and experimental groups to generate gastric mucosal injury. The rats were sacrificed an hour later. The effect of oral administration of plant extract on ethanol-induced gastric mucosal injury was studied grossly and histology. The level of lipid peroxidation (malondialdehyde-MDA), superoxide dismutase (SOD) and gastric wall mucus were measured from gastric mucosal homogenate. The ulcer control group exhibited severe gastric mucosal injury, and this finding was also confirmed by histology of gastric mucosa which showed severe damage to the gastric mucosa with edema and leucocyte infiltration of the submucosal layer. Pre-treatment with plant extract significantly reduced the formation of ethanol-induced gastric lesions, and gastric wall mucus was significantly preserved. The study also indicated a significant increase in SOD activity in gastric mucosal homogenate, whereas a significant decrease in MDA was observed. Acute toxicity tests did not show any signs of toxicity and mortality up to 5 g/kg. The ulcer protective effect of this plant may possibly be due to its preservation of gastric wall mucus along with increased SOD activity and reduction of oxidative stress (MDA). The extract is non-toxic, even at relatively high concentrations.     

Electrodeposition of selenium from 1-ethyl-3-methyl-imidazolium trifluromethylsulfonate

The electrodeposition of thin selenium (Se) films from 1-ethyl-3-methyl-imidazolium trifluromethylsulfonate at room and elevated temperatures on gold and on copper substrates was studied under open-air conditions. The effect of bath temperature on the composition and structure of the deposited films was examined using cyclic voltammetry, chemical analysis and X-ray diffraction analysis. The obtained results showed that on gold substrate and at room temperature, a reddish Se film grows mainly in amorphous, monoclinic, rhombohedral and hexagonal structure, while at temperatures ≥90 °C, a grayish film of hexagonal and rhombohedral structure is deposited. Photoelectron spectroscopy shows that both films consist of pure Se with only slight surface contaminations by remnants from the electrodeposition. Due to the differences in phase structure and the presence of the monoclinic phase, the reddish films showed higher light absorbance. The band gap of the reddish film is close to that of pure amorphous Se reported in literature. Deposition on copper substrate leads to formation of CuSe and CuSe₂ at room temperature and at 70 °C, respectively.