Cubosomal based oral tablet for controlled drug delivery of telmisartan: formulation,in-vitro evaluation and in-vivo comparative pharmacokinetic study in rabbits

A nanoparticulate system; cubosomes has been suggested to support the controlled release of Telmisartan (TEL), a poorly water-soluble medication. Four distinctive formulae were selected according to the results of three estimated responses. The liquid cubosomes were successfully adsorbed onto Aerosil 380 to form granules. The formulae were evaluated for their flow properties. The best granules were compressed into tablets suitable for oral administration. The tablets were evaluated for its performance. The in vivo study of the best selected cubosomal tablets was checked after oral administration in the blood of albino rabbits utilizing an HPLC method. Results revealed that the highest EE was shown in formulae C5 (59.68?±?1.3). All the prepared formulae had particle size less than 500?nm with PDI < 0.5 and the highest zeta potential results were observed in C5, C7, C9, C11 and C12 (>30?mv). A7 and A9 prepared using Aerosil 380 showed a perfect flowability. After 1?h of dissolution testing, the commercial product showed a 66% drug release while the release of all cubosomal formulae didn’t exceed 35% during the first hour reaching a 85% of the drug released at the end of 24?h. A7 was selected for the in vivo study; T_max of TEL absorption is increased for cubosomal formula by three folds indicating sustained release pattern. The relative bioavailability is also increased by 2.6 fold. The investigation proposed the rationality of cubosome to figure an effective controlled release tablets to improve its bioavailability and expand its activity.     

Influence of the pre-treatment on the structure and reactivity of Ir/γ-Al2O3 catalysts in the selective reduction of nitric oxide by propene

The selective catalytic reduction (SCR) of nitric oxide by propene over Ir/Al₂O₃ under lean-burn conditions (1000 vpm NO, 2000 vpm C₃H₆, 500 vpm CO, 10 vol.% O₂) was studied. The activity was shown to be strongly enhanced after exposure of the catalyst at 600°C under the reaction mixture, irrespective of the oxidising or reducing pre-treatment. Simultaneously, the Ir dispersion decreased from 78 to 10%. The influence of each component of the reaction mixture on the activation process was examined. The presence of both CO and O₂ was found to be necessary to activate Ir/Al₂O₃ while NO would not be. In situ FT-IR results revealed that initially fully oxidised Ir particles partially reduced in the feed to form Ir⁰ reduced surface sites (νCO at 2060 cm⁻¹) which adsorbed CO up to 350–400°C. The activation under reactants was related to the formation of these sites. The presence of reduced (or partially reduced) Ir sites, possibly siting at the surface of IrO₂ particles and stabilised by CO adsorption, was proposed to be responsible for the SCR activity.     

Spectroscopic photon emission microscopy: a unique tool for failure analysis of microelectronics devices

Photon emission microscopy (PEM) is a technique used commonly for failure analysis of microelectronics chips. This technique has it limitations: it can only be used to indicate the place of the failure. In most cases, this is not enough to allow a definition of the failure, i.e. to find out whether it is due to a gate oxide breakdown, a metal short, a junction spiking, etc. In this paper spectral PEM is discussed. It is shown that the spectrum of the light emitted by the failure may offer valuable information about the identity of the failure.     

Influence of Optimized Tire Shreds on Shear Strength Parameters of Sand

This paper presents the usefulness of optimizing the size of waste tire shreds on shear strength parameters of sand reinforced with shredded waste tires. A relatively, uniform sand has been mixed with randomly distributed waste tire shreds with rectangular shape and compacted at 2° of compaction. Waste tire shreds were prepared with a special cutter in three widths of 2, 3, and 4?cm and various lengths for each shred width. Three shred contents of 15, 30, and 50% by volume were chosen and mixed with the sand to obtain a uniformly distributed mixture. In order to compare the shear strength of different sand–tire shred samples, two compaction efforts in terms of sand matrix unit weights of 15.5 and 16.8?kN/m3 were considered. The results show that the influencing parameters on shear strength characteristics of sand–shred mixtures are normal stress, sand matrix unit weight, shred content, shred width, and aspect ratio of tire shreds. With the selected widths of shreds, compaction efforts, shred contents, and the variations of aspect ratios, it is possible to increase the initial friction angle ?1 up to 113.5%, that is ?1 = 67°. The average value for the influence of aspect ratio variations on increase in friction angle of the mixtures for all tests has been found to be about 25%. These average values for lower and higher compacted samples containing different widths and aspect rations were 37.6 and 17.2%, respectively. It has been investigated that for a given width of tire rectangular shreds, there is solely a certain length, which gives the greatest initial friction angle for sand–tire shred mixtures. This is the main contribution of this paper.     

Efficiency of modified skimmed milk base media to achieve high exopolysaccharide/cell ratios by Lactobacillus delbrueckii subsp. bulgaricus SZ2 in optimised conditions defined by the response surface methodology

Exopolysaccharide (EPS) production by Lactobacillus delbrueckii subsp. bulgaricus SZ2 was optimised in modified MRS (M‐MRS) using the response surface methodology (RSM). Maximum EPS production was 74.3 ± 2 mg/L, and the optimised values of the three variables predicted for maximum EPS production included a temperature of 38.7 °C, Bacto‐casitone and glucose concentrations of 24.5 and 29.6 g/L, respectively. To compare EPS production in MRS and skimmed milk (SM), the kinetics of EPS formation and growth were monitored in M‐MRS, SM, skimmed milk plus 2% additional sucrose (Suc‐SM) and skimmed milk containing Bacto‐casitone (20 g/L) and yeast nitrogen base (5 g/L) (BY‐SM). EPS production in all the media tested seemed to be growth‐related. The EPS/cell ratios were determined to be 3.12 × 10^?10, 1.43 × 10^?10, 4.42 × 10^?11 and 3.16 × 10^?11 mg/cell, in Suc‐SM, SM, M‐MRS and BY‐SM, respectively, clearly indicating the greater effect of C/N ratio when cell behaviour in EPS production is considered.     

Synthesis, Surface, Thermodynamic Properties of Some Biodegradable Vanillin-Modified Polyoxyethylene Surfactants

Four water-soluble non-ionic ethoxylated surfactants based on vanillin were synthesized (VE₁₅, VE₂₀, VE₄₀, and VE₆₀). The chemical structures of these surfactants were confirmed using FT-IR and ¹H-NMR spectra. The molecular weights of the compounds were determined using viscosity measurements and gel permeation chromatography. Surface tension as a function of the concentration of the surfactant in aqueous solution was measured at 25, 40 and 55?°C. From these measurements, the critical micelle concentration (CMC), effectiveness (??_cmc), efficiency (pC₂₀), maximum surface (??_max) excess and minimum surface area (A _min), were calculated. The surface activity measurements showed their high tendency towards adsorption and micellization and their good surface tension reduction, and low interfacial tension. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The thermodynamic parameters of micellization (??G _mic, ??H _mic, ??S _mic) and adsorption (??G _ads, ??G _ads, ?S _ads) showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The biodegradability of the prepared surfactants was tested in river water using die-away method and showed their readily biodegradation in the open environment.