• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.4
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• pp.297-304
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• 2021

In this study, we prepared a pigmented skin model, KeraSkin-M^TM for the in vitro evaluation of whitening agents. For the purpose of complementing the existing mono-layer cell culture testing method, KeraSkin-M^TM was produced through the co-culture of human skin-derived keratinocytes and melanocytes. The efficacy of four well-known whitening agents (arbutin, ascorbic acid, kojic acid, niacinamide) was evaluated in KeraSkin-M^TM in order to assess its usefulness in assessing whitening efficacy. As a result, it was possible to observe additional details such as the distribution of melanin granules and melanin capping in each skin layer through KeraSkin-M^TM, which was previously difficult to assess in the traditional 2D cell culture system. In addition, quantification through image analysis of KeraSkin-M^TM allowed for a statistical analysis of the whitening effects. These results suggest that the KeraSkin-M^TM can be used as a new evaluation method of evaluating whitening efficacy, as well as complement the traditional total melanin content and tyrosinase inhibition assays.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.211-216
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• 2016

Micronucleus test is genotoxicity assay for detection of micronuclei in the cytoplasm of interphase cells. The reduction and replacement of in vivo toxicity testing on animals require the development of in vitro models to predict the genotoxicity or other tests for cosmetic products. In this study, we evaluated a genotoxicity assay for topically applied chemicals using a three-dimensional human reconstructed skin model, KeraSkin$^{TM}$. Two genotoxins, mitomycin C (MMC) and methyl methanesulfonate (MMS), induced significant dose-related increases in cytotoxicity and micronuclei induction in the skin model. In contrast, two non-genotoxins, 4-nitrophenol (4-NP) and trichloroethylene (TCE), induced cytotoxicity but not micronucleus formation. In conclusion, micronucleus test using human skin model may be useful for predicting in vitro genotoxic potentials of cosmetic products.

• Toxicological Research
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• v.26 no.1
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• pp.9-14
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• 2010

The evaluation of eye and skin irritation potential is essential to ensuring the safety of human in contact with a wide variety of substances. Despite this importance of irritation test, little is known with respect to the irritation potency of lomefloxacin, a fluoroquinolone antibiotic, which has been known to cause phototoxicity with an abnormal reaction of the skin. Thus, to investigate the tendency of lomefloxacin to cause eye and skin irritation, we carried out in vitro eye irritation test using Balb/c 3T3, and in vitro skin irritation test using $KeraSkin^{TM}$ human skin model system. 3T3 neutral red uptake assay has been proposed as a potential replacement alternative for the Draize Eye irritation test. In this study, the $IC_{50}$ value obtained for lomefloxacin was 375 ${\mu}g$. According to the classification model used for determining in vitro categories, lomefloxacin was classified as moderately irritant. For evaluation of skin irritation, engineered epidermal equivalents ($KeraSkin^{TM}$) were subjected to 10 and 25 mg of lomefloxacin for 15 minutes. Tissue damage was assessed by tissue viability evaluation, and by the release of a pro-inflammatory mediator, interleukin- 1${\alpha}$. Lomefloxacin increased the interleukin-1${\alpha}$ release after 15 minutes of exposure and 42 hours of post incubation, although no decrease in viability was observed. Therefore, lomefloxacin is considered to be moderately irritant to skin and eye.

• Journal of Environmental Health Sciences
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• v.43 no.1
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• pp.77-86
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• 2017

Objectives: The purpose of this study was to compare permeation characteristics in three skin types using oil-soluble benzoic acid and water-soluble caffeine after method condition optimization based on OECD guideline 428. Methods: A Franz diffusion cell, a reliable alternative method for skin permeation, was used. One-milliliter samples were taken and immediately replaced with fresh solution in the receptor chamber at regular time intervals (1, 2, 4, 7, 10 and 24 hr). The amount of test substances was measured by LC-MS/MS. Results: The permeation rate increased dose-dependently, and the permeation orders were $KeraSkin^{TM}$ > hairless mouse full skin > human cadaver epidermis for skin types, and benzoic acid solution > caffeine solution > benzoic acid cream > caffeine cream for type of test materials. Conclusion: According to the definitions of Marzulli, benzoic acid and caffeine would be classified as 'fast' and 'moderate' compared with the permeation of other chemical species. The setting conditions and permeation characteristics performed in this study are expected to contribute to future permeation studies.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.4.1-4.10
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• 2014

Objectives Effects of nanoparticles including zinc oxide nanoparticles, titanium oxide nanoparticles, and their mixtures on skin corrosion and irritation were investigated by using in vitro 3D human skin models ($KeraSkin^{TM}$) and the results were compared to those of an in vivo animal test. Methods Skin models were incubated with nanoparticles for a definite time period and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide method. Skin corrosion and irritation were identified by the decreased viability based on the pre-determined threshold. Results Cell viability after exposure to nanomaterial was not decreased to the pre-determined threshold level, which was 15% after 60 minutes exposure in corrosion test and 50% after 45 minutes exposure in the irritation test. IL-$1{\alpha}$ release and histopathological findings support the results of cell viability test. In vivo test using rabbits also showed non-corrosive and non-irritant results. Conclusions The findings provide the evidence that zinc oxide nanoparticles, titanium oxide nanoparticles and their mixture are 'non corrosive' and 'non-irritant' to the human skin by a globally harmonized classification system. In vivo test using animals can be replaced by an alternative in vitro test.

• The Korean Journal of Pesticide Science
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• v.16 no.3
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• pp.261-266
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• 2012

It is common to use many experiment animals to evaluate the toxicity of chemicals including pesticides. For protecting animal, the concepts of 3R (Reduction, Replacement, Refinement) were introduced and in vitro alternatives methods actively have been developed all over the world. Many experimental animals for toxicological tests have been used, so that it is important to establish the alternative methods. In this study, the alternative method using reconstituted human skin model (Keraskin$^{TM}$) was conducted for classification of skin irritation on pesticides. Sixteen formulations selected on the basis of the degree of irritation were treated by Keraskin$^{TM}$ test. The percent of cell viability was measured into the culture medium collected after treatment of the pesticides for 24-72 hrs. The skin irritations of formulations were evaluated by the cell viability. In this study, The 4 formulations with mild irritation in rabbits were evaluated as nonirritant, the 6 formulations with moderate and severe irritation were evaluated as irritant in human skin model test. We suggest that the alternative test using Keraskin$^{TM}$ model could be used as toxicity evaluation for primary irritation index (P.I.I.) score of greater than or equal to 2.1 of pesticides. The further studies should be required to apply for hazardous assessment of pesticides on alternative skin irritation methods because of the interindividual variability of the sensitivity of skin irritation on pesticides.