• Journal of Pharmaceutical Investigation
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• v.33 no.2
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• pp.141-144
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• 2003

The transdermal therapeutic system (TTS) of scopolamine has various advantages over its oral dosage forms. The ideal scopolamine TTS requires high skin permeation rate in short time after it is applied on the skin. In order to increase the initial skin permeation rate of scopolamine from TTS, various permeation enhancers were employed. Enhancers employed were fatty acids (oleic and linolenic acids), cyclic monoterpenes (menthol, camphor, cineole and limonene) and others (isopropyl myristate, sodium lauryl sulfate and glyceryl monostearate). The concentration of enhancers in the base were fixed to 5% (w/w). While fatty acids had little enhancing effect on the skin permeation of scopolamine, cyclic monoterpenes, isopropyl myristate and sodium lauryl sulfate resulted in $1.5{\sim}2.6-fold$ higher skin permeation rate of the drug compared to the control. However, lag time was not affected by enhancers studied.

• Biomolecules & Therapeutics
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• v.25 no.4
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• pp.434-440
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• 2017

S-methyl-$\small{L}$-methionine (SMM), also known as vitamin U, is commercially available as skin care cosmetic products for its wound healing and photoprotective effects. However, the low skin permeation expected of SMM due to its hydrophilic nature with a log P value of -3.3, has not been thoroughly addressed. The purpose of this study thus was to evaluate the effect of skin permeation enhancers on the skin permeation/deposition of SMM. Among the enhancers tested for the in vitro skin permeation and deposition of SMM, oleic acid showed the most significant enhancing effect. Moreover, the combination of oleic acid and ethanol further enhanced in vitro permeation and deposition of SMM through hairless mouse skin. Furthermore, the combination of oleic acid and ethanol significantly increased the in vivo deposition of SMM in the epidermis/dermis for 12 hr, which was high enough to exert a therapeutic effect. Therefore, based on the in vitro and in vivo studies, the combination of oleic acid and ethanol was shown to be effective in improving the topical skin delivery of SMM, which may be applied in the cosmetic production process for SMM.

• Journal of Environmental Health Sciences
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• v.26 no.2
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• pp.91-96
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• 2000

We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying drug delivery system(DDS). Natural gums were selected as material of TTS. The permeation of natural gums ointment containing drug in rat skin using diffusion cell model. Permeation properties of materials were investigated for water soluble drug such as riboflavin in vitro. We used glycerin, PEG 600 and oleic acid as enhancers. Since dermis has more hydration than the stratum corneum, skin permeation rate at steady state was highly influenced when glycerin was used in riboflavin. The permeation rate of content enhancer and drug was found to be faster than that of content riboflavin only. These results showed that skin permeation rate of drug across the composite was mainly dependent on the property of ointment base and drug. All the gum ointment tested showed good safety. Proper selection of the materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.19-21
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• 2009

This study was performed to examine the possibility of increasing the level of furosemide permeation from the ethylene-vinyl acetate (EVA) matrix through the skin by incorporating various enhancers in the EVA matrix. The effects of the enhancers on the level of furosemide permeation through the skin were evaluated using Franz diffusion cells with intact excised rat skins. The enhancers examined were the fatty acids (saturated, unsaturated), the pyrrolidones, the propylene glycol derivatives, the glycerides and the non-ionic surfactants. Among the enhancers used, polyoxyethylene-2-oleyl ether (a non-ionic surfactant) showed the best enhancement. The polyoxyethylene 2-oleyl ether as a permeation enhancer could be used for development of furosemide-EVA transdermal matrix system.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.313-319
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• 2002

Rat skin permeation of various nonsteroidal antiinflammatory drugs (NSAIDs) was investigated in vitro using Franz diffusion cell at $37^{\circ}C$. The effect of various skin permeation enhancers was also observed as a preliminary study of developing transdermal delivery systems of NSAIDs. Lipophilicity of NSAIDs was determined from thε partition coefficient (log P) in 1-octanol/water and 1-octanol/IPB mutual-saturated solutions. The solubility was determined in water, isotonic phosphate buffer (IPB), and propylene glycol (PG) at $37^{\circ}C$. The rat skin permeation rate of acetaminophen, piroxicam, and aceclofenac was almost negligible, although they were saturated in PG. Addition of 1 % permeation enhancer increased the permeation rate of ketoprofen, ketorolac, and diclofenac. However, the skin permeation rate of ibuprofen did not increase with the addition of various enhancers. Among the permeation enhancers testεd, oleic acid was the most effective for various NSAIDs. Based on the daily dose, lipophilicity, and the skin permeation ratε achieved in this study, ketoprofen and ketorolac seem to be the most promising drug candidates for transdermal delivery systems, especially when formulated with unsaturated fatty acids, such as oleic acid.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.392-399
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• 2002

The effects of vehicles and penetration enhancers on the in vitro permeation of melatonin through dorsal hairless mouse skin were investigated. Propylene glycol laurate (PGL), isopropyl myristate (IPM), propylene glycol monolaurate (PGML) and propylene glycol monocaprylate (PGMC) showed high permeation fluxes and PGL, PGML and PGMC decreased lag time significantly. In both of the binary co-solvents of diethylene glycol monoethyl ether (DGME)-PGL and DGME-IPM, the highest fluxes were achieved at 20% of DGME, which were $10.5{\pm}1.5$ and $9.1{\pm}2.4{\;}{\mu\textrm{g}}/cm^2/h$, respectively. Among fatty acids used as a permeation enhancer, capric acid and oleic acid in DGME-PGL (80:20 v/v) showed relatively high enhancing effects. Capric acid also shortened the lag time of melatonin from $2.4{\pm}0.7{\;}to{\;}1.3{\pm}0.2{\;}h$. Oleic acid, however, failed to shorten the lag time. Therefore, for effective solution formulations in terms of permeation flux and lag time, capric acid-containing DGME-PGL (80 : 20 v/v) could be used to enhance the skin permeation of melatonin.

• 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)

• YAKHAK HOEJI
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• v.58 no.3
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• pp.171-180
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• 2014

To enhance the in vitro permeation of lovastatin through excised hairless mouse and human cadaver skins, solubility was determined in various hydrophilic and lipophilic vehicles, and the effects of vehicles and penetration enhancers on the skin permeation from solution formulations were investigated. Solubility of lovastatin was highest in N-methyl-2-pyrrolidone (NMP) ($278.2{\pm}10.1$ mg/ml) and dimethyl sulfoxide (DMSO) ($162.2{\pm}9.7$ mg/ml). Among different pure vehicles used, NMP, DMSO, propylene glycol and isopropyl myristate provided some drug permeation ($6.9{\pm}1.1$, $5.9{\pm}1.6$, $3.0{\pm}0.5$ and $2.2{\pm}0.3{\mu}g/cm^2$ at 24 hr, respectively) through hairless mouse skin. The addition of oleic acid, linoleic acid and oleyl alcohol to DMSO showed the maximum permeation at around 5 v/v%, however, capric acid and caprylic acid had no enhancing effect. The increase of enhancer concentrations showed bell-shaped permeation rate, suggesting the presence of optimal concentration in lovastatin penetration. Increasing donor concentration from 10 mg/ml to 80 mg/ml in DMSO and a cosolvent of DMSO, NMP and DGME (3 : 3 : 4 v/v) did not show significant dose dependent permeation in both hairless mouse and human cadaver skins. The maximum lovastatin flux through human cadaver skin was found to be $0.87{\pm}0.46{\mu}g/cm^2$/hr with 5 v/v% linoleic acid and donor dose of 4 mg/0.64 $cm^2$ in the cosolvent. These results suggest that transdermal delivery of lovastatin would be feasible by establishing the optimal concentrations of donor dose and unsaturated fatty acids in appropriate vehicles.

• Journal of Pharmaceutical Investigation
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• v.33 no.2
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• pp.129-133
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• 2003

In order to evaluate the effects of vehicles and penetration enhancers on skin permeation of apomorphine, the skin permeation rates of apomorphine from vehicles of different composition were determined using Franz diffusion cells fitted with excised rat skins. Solubility of apomorphine in various solvents was investigated to select a vehicle suitable for the percutaneous absorption of apomorphine. The solvents used were propylene glycol (PG), $Transcutol^{\circledR},\;Labrasol^{\circledR},\;Labrafac hydro WL^{\circledR},\;Labrafil WL 2609 BS^{\circledR}$ and isopropyl alcohol. Even though permeation rates of apomorphine from each vehicle were low $(0.008-0.36\;{\mu}g/cm^2/hr)$, the combination of PG and $Labrafac^{\circledR}$ increased it significantly. The permeation rates of apomorphine from $PG/Labrafac^{\circledR}$ mixtures increased as the volume fraction of PG in the mixture increased. The maximum permeation rate of $18\;{\mu}g/cm^2/hr$ was achieved at 30% of PG, which decreased with further increase of PG fraction. A series of fatty acids, alcohols and monoterpenes were employed as penetration enhancers. Incorporation of each enhancer in the $PG/Labrafac^{\circledR}$ (30:70) mixture at the level of 10% improved the skin permeation significantly. The highest permeation rate, $117\;{\mu}g/cm^2/hr$, was attained with myristic acid.

• 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.