• Proceedings of the KSME Conference
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• 2001.11b
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• pp.622-627
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• 2001

Microjet flows are often encountered in many industrial applications of micro-electro-mechanical systems as well as in medical engineering fields such as a transdermal drug delivery system for needle-free injection of drugs into the skin. The Reynolds numbers of such microjets are usually several orders of magnitude below those of larger-scale jets. The supersonic microjet physics with these low Reynolds numbers are not yet understood to date. Computational modeling and simulation can provide an effective predictive capability for the major features of the supersonic microjets. In the present study, computations using the axisymmetic, compressible, Navier-Stokes equations are applied to understand the supersonic microjet flow physics. The pressure ratio of the microjets is changed to obtain both the under- and over-expanded flows at the exit of the micronozzle. Sonic and supersonic microjets are simulated and compared with some experimental results available. Based on computational results, two microjets are discussed in terms of total pressure, jet decay and supersonic core length.

• YAKHAK HOEJI
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• v.56 no.3
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• pp.158-163
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• 2012

Lidocaine has been studied for many chronic pain conditions, including postherpetic neuralgia (PHN) and recently it has also been increasingly used in transdermal drug delivery systems. In this study, pharmacokinetics of a lidocaine patch was studied in four hairless male rats. The plasma concentration was determined by a validated LC/MS/MS method after applying a $3{\times}2cm^2$ (30mg) patch for 12 hours. From the plasma lidocaine concentration vs time curves, $AUC_{0-20h}$, Cmax, and Tmax of lidocaine patch were $2,926.32{\pm}335.28ng{\cdot}h/ml$, $256.86{\pm}29.63ng/ml$, and $6.00{\pm}2.31h$, respectively.

• The Journal of Korean Physical Therapy
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• v.14 no.2
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• pp.219-233
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• 2002

스테로이드성 소염진통제인 트리암시놀론 겔의 피부투과도를 향상시키기 위하여 초음파를 조사하여 약물의 투과도에 미치는 영향을 비교하였다. 트리암시놀론을 함유한 수용성 겔을 제조하여 물리화학적 시험을 실시하였으며 carbopol을 기제로한 겔이 우수한 제제학적 특성을 보였다. 초음파 조사가 약물의 투과도에 미치는 영향을 알아보기 위하여 hairless mouse의 적출 피부에 대한 in vitro 흡수 실험을 실시하였다. 트리암시놀론 겔 음파영동군이 트리암시놀론겔 단독 처치군에 비하여 투과도가 유의적으로 향상되었다. 특히 주파수가 1MHz인 지속초음파를 고 강도로 적용시 피부투과도의 향상이 더욱 두드러졌다. 따라서 트리암시놀론 겔 도포 후 초음파를 이용한 음파영동 경피흡수가 단독의 겔 처치보다 피부투과에 유용할 것으로 사료된다.

• Biomolecules & Therapeutics
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• v.9 no.4
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• pp.298-306
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• 2001

To develop a novel transdermal delivery system of loxoprofen (LP), a potent antiinflammatory and analgesic agent, the effects of vehicle composition and drug loading dose on the skin permeation property were investigated. And in vivo skin absorption property studied by analysing the $C_{max}$ and AUC was investigated after applying the developed plaster systems on rabbit back skin. Addition of isopropyl myristate (IPM) and IPM-diethylene glycol monoethyl ether (DGME) cosolvent in the plaster showed higher permeation rates than those from propylene glycol laurate-DGME cosolvent systems. As the concentration of LP in the plaster increased from 0.56 mg/$\textrm{cm}^2$ to 1.19 mg/$\textrm{cm}^2$, the drug release and skin permeation rates increased linearly. At loading dose of 1.19 mg/$\textrm{cm}^2$, the flux reached 35.6 $\mu$g/$\textrm{cm}^2$/hr. New LP plasters showed a good adhesive property onto skin, and showed no crystal formation. The AU $C_{0-24hr}$ and $C_{max}$ after dermal application of LP plaster (60 mg/70 $\textrm{cm}^2$) were found to be 6951$\pm$230 ng.hr/ml and 400$\pm$44 ng/ml, respectively. And the plasma concentration maintained above 300 ng/ml up to 24 hr period. In the carrageenan-induced rat paw edema test, LP plaster showed similar inhibition rate with marketed ketoprofen (Ketoto $p^{R}$) plaster.aster.r.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.195-201
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• 2022

The main objective of this work is to prepare Rehmannia glutinosa extract (RE) incorporated functional chitosan (CH) based biomaterials and evaluate their physical properties, RE release properties, inhibitory effect of melanogenesis, and antioxidant and elastase inhibitory activities. RE incorporated CH based biomaterials were synthesized by a casting method and UV curing process. The surface and cross sections of prepared biomaterials were characterized by a field emission scanning electron microscope (FE-SEM). The physical properties such as tensile strength and elongation at break were also investigated. To apply the transdermal drug delivery system, RE release properties were examined with pH 4.5, 5.5, and 6.5 buffer solutions and artificial skin test at 36.5 ℃. Results indicated that RE release of RE incorporated biomaterials with/without the addition of plasticizers [glycerol (GL) and citric acid (CA)] at pH 6.5 was about 1.10 times higher than that of at pH 4.5. In addition, results of the artificial skin test verified that RE was released constantly for 6 h. To verify the applicability of the prepared biomaterials, tyrosinase, 2,2-diphenyl-1-picrylhydrazyl (DPPH), and elastase assays were investigated. Results indicated that RE incorporated biomaterials added CA exhibited tyrosinase activation, DPPH radical scavenging activity rate, and elastase activation of 45.12, 89.40, and 59.94%, respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.105-113
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• 2010

This study introduces a flexible approach to enhance skin permeation by using ethosomes with deformable lipid membranes as well as controllable sizes. To demonstrate this, a set of ethosomes encapsulating an anti-hair loss ingredient, Triaminodil$^{TM}$, as a model drug, were fabricated with varying their size, which was achieved by solely applying the different level of mechanical energy, while maintaining their chemical composition. After characterization of the ethosomes with dynamic light scattering, transmission electron microscopy, and deformability measurements, it was found that their membrane deformability depended on the particle size. Moreover, studies on in vitro skin permeation and murine anagen induction allowed us to figure out that the membrane deformability of ethosomes essentially affects delivery efficiency of Triaminodil$^{TM}$ through the skin. It was noticeable in our study that there existed an optimum particle size that can not only maximize the delivery of the drug through the skin, but also increase its actual dermatological activity. These findings offer a useful basis for understanding how ethosomes should be designed to improve delivery efficiency of encapsulated drugs therein in the aspects of changing their length scales and membrane properties.

• Journal of the Korean Chemical Society
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• v.40 no.9
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• pp.640-648
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• 1996

Crosslinked chitosan was prepared from chitin after reaction with epichlorohydrin followed by deacetylation at C2-position. Epidermal releasing polymeric matrix was prepared after swelling crosslinked chitosan with distilled water and adding silver sulfadiazine and glycerine as a plasticiser. The release behavior of silver sulfadiazine from polymeric matrix was studied in pH 7.4 phosphate buffer solution by varing the drug content, glycerine concentration, and the thickness of the matrix. The drug release time was delayed by increasing the content of silver sulfadiazine and the thickness of the matrix, whereas decreased as glycerine concentration increased. The apparent constant(K) of release rate was independent upon the matrix thickness, but was proportional to the content of drug or glycerine of crosslinked chitosan matrix. These results indicated that chitosan matrix showed some potential as a drug delivery system for transdermal therapeutic application.

• Toxicological Research
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• v.29 no.2
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• pp.87-90
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• 2013

The potential role of topical valproate (VPA) in hair regrowth has been recently suggested. However, safety reports of VPA as a topical formulation are lacking. Therefore, in the present study, we investigated whether VPA causes skin irritation in humans. We first performed a cell viability test and showed that VPA did not exhibit toxicity toward HaCaT keratinocytes, fibroblasts, and RBL-3H mast cells. We then performed clinical patch test and skin irritation test through transdermal drug delivery with the help of microneedle rollers. No significant findings were obtained in the clinical patch test. In the skin irritation test, only 1 patient showed erythema at 1 hr, but the irritation reaction faded away within a few hours. Erythema and edema were not observed at 24 hr. We concluded that VPA has minimal potential to elicit skin irritation. Therefore, we consider that VPA can safely be applied to human skin.

• Journal of Pharmaceutical Investigation
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• v.33 no.1
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• pp.29-36
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• 2003

Clenbuterol, a selective ${\beta}_2-adrenergic$ receptor stimulant, has been introduced as a potent bronchodilator for patients with bronchial asthma, chronic obstructive bronchial disease, chronic bronchitis and pulmonary emphysema. The percutaneous permeation of clenbuterol was investigated in hairless mouse skin after application of 50/50 buffer(pH 10)/propylene glycol solvent mixture. The enhancing effects of various penetration enhancers such as terpenes, non-ionic surfactants, pyrrolidones, fatty acids and some other enhancers on the permeation of clenbuterol were evaluated using Franz diffusion cell. Among terpenes studied, 1,8-cineole was the most effective enhancer, which increased the permeability of clenbuterol approximately 39.33-fold compared with the control without penetration enhancer, followed by menthone with enhancement ratio of 23.57. Nonionic surfactants did not have significant enhancing effects. N-Lauryl-2-pyrrolidone increased the permeability of clenbuterol approximately 4.51-fold compared with the control. Lauric acid increased the permeability of clenbuterol approximately 35.57-fold with decreasing the lag time from 2.64 to 0.52 hr. Oleic acid, linoleic acid, linolenic acid and capric acid showed enhancement ratio of 22.62, 19.60, 17.45 and 16.51, respectively. $Labrafil^{\circledR}$ enhanced the permeability of clenbuterol 9.24-fold compared with that without enhancer.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.595-600
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• 2000

Transdermal delivery of ketorolac tromethamine, a potent non-narcotic analgesic, through human cadaver skin was investigated in vitro. A mixture of ethanol/water (40/60) containing 0, 1, 3, 5, and 8 (w/v)% L-menthol were used as a vehicle and penetration enhancer respectively. The permeation of ketorolac through human cadaver skin from saturated drug solution was evaluated at $37^{\circ}C$ with modified Franz diffusion cell. The in vitro skin flux and lag time were $1.23\;{\pm}\;0.11\;{\mu}g/cm^2{\cdot}hr$ and $5.56\;{\pm}\;0.34\;hr$, respectively. The cumulative amount of penetrated ketorolac containing L-menthol in ethanol/water (40/60) binary system was increased by the following order; 3%, 5%, 8%, 1%, 0%, and the lag time was decresed by the following order; 3%, 5%, 8%, 0%, 1%. The results suggested that a potential use of 3% L-methol is an effective penetration enhancer of ketorolac tromethamine through the human cadaver skin.