Electrophoretic separation and characterisation of gliadin fractions from isolates and nanoparticulate drug delivery systems

Steady electro-osmotic flow of a micropolar fluid in a microchannel

We have formulated and solved the boundary-value problem of steady, symmetric and one-dimensional electro-osmotic flow of a micropolar fluid in a uniform rectangular microchannel, under the action of a uniform applied electric field. The Helmholtz–Smoluchowski equation and velocity for micropolar fluids have also been formulated. Numerical solutions turn out to be virtually identical to the analytic solutions obtained after using the Debye–Hückel approximation, when the microchannel height exceeds the Debye length, provided that the zeta potential is sufficiently small in magnitude. For a fixed Debye length, the mid-channel fluid speed is linearly proportional to the microchannel height when the fluid is micropolar, but not when the fluid is simple Newtonian. The stress and the microrotation are dominant at and in the vicinity of the microchannel walls, regardless of the microchannel height. The mid-channel couple stress decreases, but the couple stress at the walls intensifies, as the microchannel height increases and the flow tends towards turbulence.

Clarithromycin- and omeprazole-containing gliadin nanoparticles for the treatment of Helicobacter pylori

The aim of the present work was to prepare and evaluate the oral mucoadhesive sustained release nanoparticles of clarithromycin and omeprazole in order to improve patient compliance by improving its therapeutic effect and reducing its dose-related side effects. The clarithromycin- and omeprazole-containing gliadin nanoparticles were prepared by the desolvation method using Pluronic F-68 as a stabilizing agent. The results showed that this method is reproducible, easy, and leads to the efficient entrapment of drug as well as formation of spherical particles ranging from 400 to 650 nm. The maximum percentage of drug entrapment for clarithromycin and omeprazole was 81.7 +/- 2.2 and 73.7 +/- 3.9%, respectively, whereas the percentage of yield of the system was 85.1 +/- 1.9%. The sustained release behavior of gliadin nanoparticles was evaluated in phosphate-buffered saline (pH 7.4) and simulated gastric fluid (pH 1.2), at 37 +/- 1 degrees C. Their mucoadhesive properties were determined by in vitro and in vivo methods. In vitro antibacterial activity of the formulations was performed on isolated culture of Helicobacter pylori, which showed greater eradication effect of dual therapy entrapped formulations when compared with single therapy containing formulations and plain drugs.

Analytical solution of combined electroosmotic/pressure driven flows in two-dimensional straight channels: finite Debye layer effects

Analytical results for the velocity distribution, mass flow rate, pressure gradient, wall shear stress, and vorticity in mixed electroosmotic/pressure driven flows are presented for two-dimensional straight channel geometry. We particularly analyze the electric double-layer (EDL) region near the walls and define three new concepts based on the electroosmotic potential distribution. These are the effective EDL thickness, the EDL displacement thickness, and the EDL vorticity thickness. We show that imposing Helmholtz-Smoluchowski velocity at the edge of the EDL as the velocity matching condition between the EDL and the bulk flow region is incomplete under spatial bulk flow variations across the finite EDL. However, the Helmholtz-Smoluchowski velocity can be used as the appropriate slip velocity on the wall. We discuss the limitations of this approach in satisfying the global conservation laws.

Bioadhesive potential of gliadin nanoparticulate systems

The objective of this work was to prepare, characterise and evaluate the adhesive potential of gliadin nanoparticulate carriers. Firstly, lectin-nanoparticle conjugates were obtained by the carbodiimide (CDI) covalent binding of Dolichos biflorus lectin (DBA) to the surface of gliadin nanoparticles (NP) containing carbazole (as a model lipophilic drug). The DBA binding efficiency was favoured in mild acidic conditions. Similarly, a CDI concentration of about 0.63 mg/mg nanoparticles, acting during at least 1 h, provided binding efficiencies of about 50% bulk lectin. Under optimised experimental conditions, the DBA conjugates showed a size of around 500 nm and the amount of loaded carbazole and the DBA content were calculated to be around 15 and 23.5 microg/mg, respectively. The bioadhesive activity of NP and DBA conjugates was determined in samples of small and large rat intestinal mucosa. The amount of adsorbed NP was calculated to be around 8 and 4 g/m(2) in the small and large intestine, respectively. This high capacity to interact with the mucosa may be explained by gliadin composition. In fact, gliadin is rich in neutral and lipophilic residues. Neutral amino acids can promote hydrogen bonding interactions with the mucosa, while the lipophilic components can interact with the biological tissue by hydrophobic interactions. The bioadhesive activity of DBA conjugates was calculated to be about 2 g/m(2) in the small intestine and greater than 4 g/m(2) in the caecum and distal colon. These degrees of interaction were always significantly higher than those obtained with controls. Finally, DBA did not provide the specificity for interaction with Peyer's patches. In summary, gliadin nanoparticles show a high capacity of non-specific interaction with the intestine, whereas DBA binding to the surface of these carriers provided a greater specificity for colonic mucosa.