• YAKHAK HOEJI
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• v.29 no.5
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• pp.234-245
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• 1985

To clarify the diffusional behavior of p-aminbenzoic acid esters in the presence of polyethylene glycol 400, cellulose membrane permeation rate, solubility and viscosity of p-aminobenzoic acid methyl ester, benzocaine and butamben were determined with PEG solutions of various concentrations. With an increase in PEG concentrations permeation rates from solutions; decreased due to an increase in viscosity of the solution. From suspensions, however, permeation rates increased due to an increase in solubility and when the initial drug concentration was constant, permeation rates were found to be greatest from the PEG-water system with the PEG concentration which transported from the solution to the suspension. Permeation rate of 4.0mg/ml p-aminobenzoic acid methyl ester was $26.51\mu$g/ml$\cdot$hr from 5g/100ml PEG solution, and that of 4.0mg/ml benzocaine was $13.17{\mu}g/ml{\cdot}hr$ from 15g/100ml PEG, solution, and that of 2.0mg/ml butamben was $3.8{\mu}g/ml{\cdot}hr$ from 10g/100ml PEG solution. Permeation rate was 7.0 fold in p-aminobenzoic acid methyl, ester and 3.5 fold in benzocaine compared to butamben.

• Journal of Pharmaceutical Investigation
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• v.26 no.4
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• pp.263-271
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• 1996

Sulconazole nitrate(SCN), an imidazole derivative which has been effective in the treatment of dermatophytosis, tinea versicolor and candidiasis, was formulated as a gel containing drug, poloxamer 407, ethanol and propylene glycol. The resulting SCN gels were evaluated with respect to their viscosity, drug release rate, skin permeation rate. The apparent viscosity of SCN gel increased in proportion to poloxamer 407, drug and propylene glycol concentration. In case ethanol was added, the apparent viscosity decreased. The drug release rate of SCN gel increased in proportion to temperature and ethanol concentration. But the drug release rate decreased as the concentration of poloxamer 407 increased. The increase of drug concentration induced nonlinear increase of drug release rate. When propylene glycol was added at the level of 10%, the drug release rate increased but from 15% it decreased. The skin permeation rate decreased in high concentration of poloxamer 407. The skin permeation rate of SCN gel containing 15% ethanol increased about twice than that of gel without ethanol. The increase of drug concentration induced nonlinear increase of skin permeation rate. When propylene glycol was added at the level of 10%, the skin permeation rate increased but from 15% it decreased.

• Journal of Pharmaceutical Investigation
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• v.30 no.2
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• pp.119-125
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• 2000

In an attempt to develop a non-aqueous liquid formulation of practically insoluble biphenyl dimethyl dicarboxylate (DDB), dissolution and permeation studies were performed. Various non-aqueous DDB solutions were formulated and filled into empty hard capsules. Dissolution rates of a new formulation were compared with those of commercially available DDB preparations using one and eight dose units. Dissolution rates after 2 hr of DDB tablets (DDB 25 mg), hard capsules (DDB 7.5 mg) and soft capsules (DDB 7.5 mg) on market and new formulation (DDB 7.5 mg) were 6.3, 15.0, 84.5 and 98.0%, respectively. Higher doses (8 units) resulted in a supersaturation within one hr of dissolution, and dissolved amounts were reduced markedly. Due to the saturation and precipitation, a directly proportional dose-dissolution relationship was not observed. The addition of copolyvidone and/or glycyrrhizic acid ammonium salt to DDB solution in polyethylene glycol 300 and 400 inhibited the formation of precipitates during dissolution and markedly enhanced the rabbit duodenal permeation of DDB. From the site-specific gastrointestinal permeation studies, it was found that permeation rates of DDB after mixing of non-aqueous DDB solutions with aqueous buffered solutions were faster in the order of $rectal\;<\;colonic\;{\risingdotseq}\;ileal\;{\risingdotseq}\;duodenal\;<\;jejunal\;<\;gastric$.

• Membrane Journal
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• v.8 no.2
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• pp.102-108
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• 1998

Permeation behavior of the semiconductor rinsing wastewater containing Si particles was examined by ultrafiltration using the polysulfone plate membrane. The permeation flux was gradually decreased with time. It was due to the growth of cake deposited on the membrane surface and the pore plugging by Si particles. Permeation flux of cross flow type was 1.4 times higher than that of the dead end flow type. Nitrogen back flushing which is the removing method of membrane fouling was superior to the water sweeping. With nitrogen back flushing, the decrease of permeation flux due to the fouling was recovered about 85 % to the initial flux in the flat plate membrane system. The rejection rate of Si particles was about 90 % and the size of Si particle in the permeate was about 70 nm.

• Geomechanics and Engineering
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• v.21 no.3
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• pp.279-288
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• 2020

The permeation grouting is a commonly used technique to improve the engineering geology condition of the soft ground. It is of great significance to predict the permeation range of the grout so as to ensure the effects of grouting. This paper conducts a theoretical analysis of jet-grouting effects in ground improvement and rotary grouting pile installation by utilizing deformation-permeation coupled poroelastic solutions based on Biot's theory and Laplace-Fourier integral transform technique. The exponential function and the intermittent trigonometric function are chosen to represent time-dependent grouting pressure usually encountered in ground improvement and rotary grouting pile installation process, respectively. The results, including the radial displacement, the hoop stress, the excess pore fluid pressure, the radial discharge, and the permeation radius of grout, are presented for different grouting time, radial positions and grouting lengths. Parametric study is conducted to explore the effects of variation of the exponent in the exponential grouting pressure-time relationship on grouting-induced responses. It is expected that the proposed solutions can be used to estimate the permeation range of grouting in ground improvement and rotary grouting pile installation.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.763-768
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• 2004

To investigate the feasibility of developing a new quercetin transdermal system, a preformulation study was carried out. Therefore, the effects of vehicles and pressure-sensitive adhesives (PSA) on the in vitro permeation of quercetin across dorsal hairless mouse skin were studied. Among vehicles used, propylene glycol monocaprylate (PGMC) and propylene glycol mono-laurate were found to have relatively high permeation flux from solution formulation (i.e., the permeation fluxes were 17.25$\pm$1.96 and 9.60$\pm$3.87 $\mu\textrm{g}$/$\textrm{cm}^2$/h, respectively). The release rate from PSA formulations followed a matrix-controlled diffusion model and was mainly affected by the amount of PSA and drug loaded. The overall permeation fluxes from PSA formulations were less than 0.30 $\mu\textrm{g}$/$\textrm{cm}^2$/h, which were significantly lower compared to those obtained from solution formulations. The lower permeation fluxes may be due to the decrease of solubility and diffusivity of quercetin in the PSA layer, considering the fact that the highest flux of 0.26 $\mu\textrm{g}$/$\textrm{cm}^2$/h was obtained with the addition of 0.2％ butylated hydroxyanisole in PGMC-diethyl-ene glycol monoethyl ether co-solvents (80-85 ： 15-20, v/v). Taken together, these observations indicate that improvement in the solubility and diffusivity of quercetin is necessary to realize fully the clinically applicable transdermal delivery system for the drug.

• Steel and Composite Structures
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• v.25 no.2
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• pp.127-139
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• 2017

In this paper, an exact analytical solution for simply supported sandwich plate which considers the permeation effect of adhesives is presented. The permeation layer is described as functionally graded material (FGM), the elastic modulus of which is assumed to be graded along the thickness following the exponential law. Based on the exact three-dimensional (3-D) elasticity theory, the solution of stresses and displacements for each layer is derived. By means of the recursive matrix method, the solution can be efficiently obtained for plates with many layers. The present solution obtained can be used as a benchmark to access other simplified solutions. The comparison study indicates that the finite element (FE) solution is close to the present one when the FGM layer in the FE model is divided into a series of homogeneous layers. However, the present method is more efficient than the FE method, with which the mesh division and computation are time-consuming. Moreover, the solution based on Kirchhoff-Love plate theory is greatly different from the present solution for thick plates. The influence of the thickness of the permeation layer on the stress and displacement fields of the sandwich plate is discussed in detail. It is indicated that the permeation layer can effectively relieve the discontinuity stress at the interface.

• Korean Journal of Metals and Materials
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• v.46 no.5
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• pp.296-303
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• 2008

Hydrogen permeation through dense palladium-based membranes has attracted the attention of many scientists largely due to their unmatched potential as hydrogen-selective membranes for membrane reactor applications. Although it is well known that the permeation mechanism of hydrogen through Pd involves various processes such as dissociative adsorption, transitions to and from the bulk Pd, diffusion within Pd, and recombinative desorption, it is still unclear which process mainly limits hydrogen permeation at a given temperature and hydrogen partial pressure. In this study, we report an all-electron density-functional theory study of hydrogen permeation through Pd membrane (using VASP code). Especially, we focus on the variation of the energy barrier of the penetration process from the surface to the bulk with hydrogen coverage, which means the large reduction of the fracture stress in the brittle crack propagation considering Griffith's criterion. It is also found that the penetration energy barrier from the surface to the bulk largely decreases so that it almost vanishes at the coverage 1.25, which means that the penetration process cannot be the rate determining process.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.74-81
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• 2007

Using the new experimental method named "filtration-permeation", the average specific resistances which plays an important role in designing cake filtration apparatus and the development of cake filtration theory were measured in this study. By this new experimental method, two kinds of average specific resistances are measured. The one from the filtration is named 'filtration average specific resistance $\alpha_{avf}$, and the other from the permeation of particle eliminated water through the pre-formed cake is named 'permeation average specific resistance $\alpha_{avf}$. The "filtration-permeation" method is applied to three different kind of suspensions(i.e. particulate suspension, pre-flocculated suspension and macro-molecule suspension) to obtain filtration and permeation average specific resistances. A theoretical procedure of cake filtration is studied based on the values of permeation average specific resistance. With the study it was concluded that the influence of the sedimentation during particlulate filtration operation could not be ignored as commonly used. And the solid content of suspension, S, which also regarded usually as constant, changes during filtration of particles. It is also verified that the exact value of solid content of cake for floe filtration could not be obtained. These significant problems are all solved by our new "filtration-permeation" experimental method.

• YAKHAK HOEJI
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• v.60 no.1
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• pp.36-45
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• 2016

This study was aimed to enhance the percutaneous absorption of tizanidine hydrochloride (TZ) across Strat-M$^{TM}$ artificial membrane and excised hairless mouse skin using various vehicles and chemical permeation enhancers. Solubility studies were performed using hydrophilic and lipophilic vehicles. To initially evaluate vehicle effects on skin permeation, Strat-M$^{TM}$ membrane was adopted using Franz-type diffusion cells loaded with 0.4 mg donor dose. Effects of fatty acids on the permeation of TZ from PG and PGMC were compared, and the effects of various hydrophilic vehicles in the presence of linoleic acid were studied using excised hairless mouse skin specimens. The mean solubility (mg/ml) of TZ in hydrophilic vehicles was higher: water > PG > DMSO > ethanol > PEG 200 > NMP > PEG 300 > PEG 400 > DGME, and solubilities in lipophilic vehicles such as PGMC, PGMC, IPM, Captex 200 and Captex 300 were much less than 1.0 mg/ml. Permeation rates through StratTM membrane from pure vehicles were in the rank order: PGMC ${\geq}$ LBF > DMSO ${\geq}$ NMP ${\geq}$ PGML ${\geq}$ PG ${\geq}$ PEG 200 ${\geq}$ DGME ${\geq}$ EtOH. However, permeation rates of TZ through hairless mouse skin from pure vehicles were very low, although PG showed the highest flux ($1.66{\pm}0.28{\mu}g/cm^2{\cdot}hr$). Therefore, PG was selected in further studies. Addition of enhancers (3 v/v%) into PG markedly increased the flux (${\mu}g/cm^2{\cdot}hr$): oleyl alcohol ($14.9{\pm}3.1$) ${\geq}$ oleic acid ($14.5{\pm}1.6$) ${\geq}$ linoleic acid ($13.7{\pm}1.3$) > capric acid ($4.4{\pm}0.6$) > caprylic acid ($2.1{\pm}0.4$). Among hydrophilic vehicles with linoleic acid, PG and DMSO revealed relatively higher permeation for TZ. Increase of donor dose in PG resulted in dose-dependent permeation fluxes. These results suggest that permeation properties of TZ from nonaqueous solutions are markedly different between Strat-$M^{TM}$ membrane and excised hairless mouse skin, and transdermal delivery of TZ would be feasible with a combination of PG and enhancers.