• Journal of Pharmaceutical Investigation
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• v.39 no.6
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• pp.437-443
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• 2009

To develop a topical bioadhesive formulation of clotrimazole for enhanced transdermal delivery, hydroxypropyl methylcellulose gel containing permeation enhancer was formulated and permeation studies were carried out. The release characteristics of the drug from the gel formulation were examined according to the receptor medium, drug concentration, and temperature. The rate of drug release from the gel increased with increasing drug concentration and temperature. The activation energy (Ea) of drug permeation, which was calculated from the slope of log P versus 1/T plots, was 14.41kcal/mol for a 1%(w/w) loading dose. The enhancer, such as saturated, unsaturated fatty acids, pyrrolidones, propylene glycol derivatives, glycerides, and non-ionic surfactants, were incorporated onto the gels to increase the amount of drug permeation into the skin. Among the enhancers used, polyoxyethylene 2-oleyl ether showed the highest level of enhancement. These results show that clotrimazole gels containing polyoxyethylene 2-oleyl ether could be used for the enhanced transdermal delivery of clotrimazole.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.68-74
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• 2015

Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.40-45
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• 2008

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23 $^{\circ}C$ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimens of fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

• Journal of Pharmaceutical Investigation
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• v.37 no.5
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• pp.311-314
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• 2007

Paclitaxel (PTX) is an antineoplastic agent approved for the treatment of ovarian and breast carcinomas. However, the use of paclitaxel as an anticancer drug is limited by its extremely poor water solubility (below $0.3\;{\mu}g/mL$). Furthermore, it has very low bioavailability when administered orally because paclitaxel is a substrate of P-glycoprotein (P-gp) efflux pump. In this study, buccal delivery of PTX was investigated as one of the alternatives for PTX delivery. Ethanol and glyceryl monooleate (GMO) were selected as permeation enhancing agents to increase solubility and permeation across buccal mucosa of PTX. At the different concentrations of ethanol solution ($30{\sim}70\;w/w\;%$), PTX permeation was studied, followed effects of GMO in the concentration range of $2.5{\sim}25%$ with ethanol vesicle. The transbuccal ability of PTX was evaluated in vitro using Franz diffusion cells mounted with rabbit buccal mucosa. As a result, incorporation of PTX into ethanol vesicle with GMO significantly enhanced the PTX permeation in rabbit buccal mucosa. Particularly, the mixtures of ethanol:water:GMO at the ratio of 50:47.5:2.5 showed the most excellent enhancing ability. The results showed a promising possibility for buccal delivery of PTX.

• Korean Journal of Materials Research
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• v.28 no.7
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• pp.428-434
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• 2018

Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.

• Corrosion Science and Technology
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• v.16 no.4
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• pp.209-225
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• 2017

Development of high strength steel requires proper understanding of hydrogen behavior since the higher the steel strength the greater the susceptibility of hydrogen assisted cracking. This paper provides a brief but broad overview on hydrogen entry and transport behavior of high-strength ferritic steels. First of all, hydrogen absorption, diffusion and trapping mechanism of the steels are briefly introduced. Secondly, several experimental methods for analyzing the physical/chemical nature of hydrogen uptake and transport in the steels are reviewed. Among the methods, electrochemical permeation technique utilized widely for evaluating the hydrogen diffusion and trapping behavior in metals and alloys is mainly discussed. Moreover, a modified permeation technique accommodating the externally applied load and its application to a variety of steels are intensively explored. Indeed, successful utilization of the modified permeation technique equipped with a constant load testing device leads to significant academic progress on the hydrogen assisted cracking (HAC) phenomenon of the steels. In order to show how the external and/or residual stress affects mechanical instability of steel due to hydrogen ingress, the relationship among the microstructure, hydrogen permeation, and HAC susceptibility is briefly introduced.

• Journal of Pharmaceutical Investigation
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• v.36 no.5
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• pp.305-308
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• 2006

Poloxamer-based hydrogel formulation for the topical delivery of ascorbic acid(AsA) was prepared and the effect of limonene on AsA skin permeation and localization was evaluated. In vitro rat skin permeation study, the AsA skin permeation of limonene-containing hydrogel was about 3 to 5 fold higher than control hydrogel. However the amount of permeated AsA was independent to the concentration of limonene. On the other hand the localized amount of AsA after 2 h increased proportion to the content of limonene. The increase in the ratio of localized AsA($Q_L$) to permeated AsA($Q_P$) was attributed to the limonene's ability of making polar pathway within stratum corneum by interacting on lipid domain of the skin and the AsA's hydration effect on the stratum corneum and effect on the protein domain of the skin.

• Journal of Pharmaceutical Investigation
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• v.28 no.1
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• pp.43-50
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• 1998

Niosomes are vesicles formed from synthetic non-ionic surfactants, offering an alternative to chemically unstable and expensive liposomes as a drug carrier. Non-ionic surfactant and cholesterol mixture film leads to the formation of vesicular system by hydration with sonication method. The formation of niosome was ascertained by negative staining of TEM. The entrapment efficiency of niosomal suspension was gradually increased with increasing the ratio of cholesterol to surfactant. It was found that the niosome with 6 : 4 (polyoxyethylene 2-cetyl ether: cholesterol) ratio was more stable than those with other ratios. The topical application of acyclovir(ACV) in the treatment of herpes simplex virus type 1(HSV-1) skin disease has a long history. There are an increasing number of reports, however, in which topical ACV therapy is not as effective as oral administration. Lack of efficacy with topical ACV has been hypothesized to reflect the inadequate delivery of drug to the skin. We investigated the permeation of niosome containing $[^{3}H]ACV$ in hairless mouse skin using Franz diffusion cell model. Permeation coefficient(P) of aqueous ACV was $6.7{\times}10^{-4}\;(cm/hr)$ and that of ACV in niosome was $23.4{\times}10^{-4}\;(cm/hr)$, suggesting about 3.5 times increase in the transdermal permeation.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.644-648
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• 2003

To investigate the feasibility of developing a new ondansetron transdermal system, the effects of vehicles and penetration enhancers on the in vitro permeation of ondansetron hydrochloride (OS) from a pressure-sensitive adhesive (PSA) matrices across dorsal hairless mouse skin were studied. Vehicles employed in this study consisted of various ratios of propylene glycol monocaprylate (PGMC)-diethylene glycol monoethyl ether (DGME) co-solvents and PGMC-propylene glycol (PG) co-solvents with 3% oleic acid. $Duro-Tak^\circledR$ 87-2100 and $Duro-Tak^\circledR$ 87-2196 were used as PSAs. The concentration of DGME in PGMC-DGME co-solvent system affected the release rate; as the concentration of DGME increased, the release rate decreased. The cumulative release amount of OS increased as the ratio of PSA to drug solution decreased. The permeation flux was also primarily affected by the amount of PSAs; as the amount decreased, the permeation flux increased. The overall fluxes from matrix formulations were significantly lower when compared to those obtained from solution formulations. The ratio of PG to PGMC did not affect permeation flux, while the lag time decreased significantly from $5.14\pm3.31 to 0.31\pm0.12$ h as the PG increased from 40% to 60%.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.234.1-234.1
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• 2003

The effects of vehicles and penetration enhancers on the in vitro permeation of ketorolac tromethamine (KT) across excised hairless mouse skins were investigated. Among pure vehicles examined, propylene glycol monolaurate (PGML) showed the highest permeation flux, which was 94.3${\pm}$17.3 mg/cm$^2$/hr. Even though propylene glycol monocaprylate (PGMC) alone did not show high permeation rate, the skin permeability of DT was markedly increased by the addition of diethylene glycol monoethyl ether (DGME); the enhancement factors were 19.0 and 17.1 at 20 and 40% of DGME, respectively. (omitted)