Permeation kinetics

Bhattachrya A, Ghosal SK. Effect of hydrophobic permeation enhancers on the release and skin permeation kinetics from matrix type transdermal drug delivery system of ketotifen fumarate. Acta Pol Pharm 2001 58(2) 101-105. 

Bhattacharya A, Ghosal SK. Permeation kinetics of ketotifen fumarate alone and in combination with hydrophobic permeation enhancers through human cadaver epidermis. Boll Chim Farm 2000 139 177-181. 

Chien, Y.W., Valia, K.H. Doshi, U.B. (1985) Long-term permeation kinetics of estradiol. V. Development and evaluation of transdermal bioactivated hormone delivery system. Drug Development and Industrial Pharmacy, 11,1195-1212. 

Ussing chamber measurements are the most commonly used method to investigate transepithelial ion transport [164, 165], They can be performed on either functional epithelia from biopsies or on cultivated epithelia. The Ussing chamber itself is more or less a U-shaped chamber, which is compartmentalized by an epithelial cell layer and solute flux between both compartments can be measured. Electrogenic ion fluxes can be measured directly by short circuit measurements or calculated from open circuit measurements [165], Non-electrogenic solute flux needs continuous concentration measurements for each compartment separately [166]. Thus, Ussing chamber experiments enable to study permeation kinetics for secretion and resorption separately [166-169] and to evaluate effects on ion transport pathways [85, 87, 90, 170]. 

Table 3 Influence of the lipid backbone on the transbilayer and permeation kinetics of functional lipids (17a)-(17i), as measured by Moss and coworkers...

High-temperature applications of perovskite-type membrane reactors require improved material performances and operational stability. The reactor microstruc-ture and architecture controls were found to be crucial for thermo-mechanical integrity and oxygen permeation kinetics. A multilayer reactor was developed, using second-phase particles to control its microstructure and a co-sintering process to control its architecture. 

The term architecture refers to the specific spatial arrangement of different materials constimting the reactor. As the membrane placed in a catalytic reactor has to satisfy various functions such as oxygen separation from air, high oxygen permeation kinetics and catalytic reactions with methane, a reactor can be defined as a Functionally... 

Kim S. Y. et al., Determination of oxygen permeation kinetics in a ceramic membrane based on the composition SrFeCoo.5O3.25-D. Solid state ionics, 1998, v.l09, p.3-4. 

Accordingly, the permeation kinetics is improved at 37°C and Cr increases more rapidly than at 25°C. An inspection of Table 15.2 reveals that the theophylline diffusion coefficient (Dj) does not sensibly vary with %P, regardless of the temperature. This can be explained with the fact that the %P increase, in the l%-4% range, does not substantially reflect in an increase of the polymeric network cross-link density, responsible for a reduction of the network mesh size, but it reflects in a higher membrane thickness. Nevertheless, it cannot be also excluded that, due to reduced theophylline dimension ( 3.8 A [118,120]), polymeric network meshes are... 

The pressure, area of membrane, thickness of membrane, and the temperature are the possible variables in the permeation kinetics. If (as is shown later, p. 413) Henry s law, S = kp applies to the solubility 8 of gas in the polymer substance,... 

Mittal, A., U.V. Sara, A. Ah, and M. Aqil, 2008. The effect of penetration enhancers on permeation kinetics of nitrendipine in two different skin models. Biol Pharm. Bull, 31(9) 1766-1762. 

Table 4.1 Literature values of the H2 permeation kinetic parameters of Pd membranes...

The permeation kinetic parameters Dy, k, and can be determined by regressing the experimental oxygen fluxes measured at different conditions with the above permeation model. Table 5.1 lists the expressions of permeation parameters for the Lao.jSro4Coo2Feo803 j perovskite membrane. The diffusion coefficients of oxygen vacancies in other perovskite membranes were also studied by the isotopic method, as summarized in Table 5.2. The activation energy for oxygen vacancy diffusion is in the range of 77 21 kj mol" [20]. 

The combination of the dimensionless numbers Da and Pe (DaPe) gives information about the reaction-permeation kinetic analysis in MRs ... 

Consistent with the structure of these nanocomposites, the addition of only 2 wt% of OMMT results in a five-fold enhancement in oxygen barrier. While TGA analyses do not indicate improved thermal stability in these nanocomposites, such a significant enhancement in oxygen barrier may nevertheless result in improved thermal and / or fire performance in situations if oxygen permeation kinetics plays a role. 

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