Sun-A Cho

A new cell-based method for assessing the eye irritation potential of chemicals: An alternative to the Draize test

Using a human corneal cell line (HCE-T cells) and 2 evaluation criteria, we developed a new alternative method to assess the eye irritation potential of chemicals. We exposed HCE-T cells to different concentrations of 38 chemicals for 1h and measured relative cell viability (RCV) as an endpoint at each concentration. Using the RCV values, we calculated the RCV50. We also exposed HCE-T cells to 3 fixed concentrations of the 38 chemicals (5%, 0.5%, and 0.05%) for 1h and measured the RCV at each concentration. Using the RCV values at 5%, 0.5%, and 0.05%, we developed a new criterion for eye irritation potential (total eye irritation score, TEIS) and estimated the ocular irritancy. We then assessed the correlation of the results of RCV50 and TEIS with those of the Draize rabbit eye irritation. Both the RCV50 and TEIS results exhibited good positive correlations (sensitivity: 80.77%, specificity: 83.33%, and accuracy: 81.58% for TEIS; sensitivity: 73.08-76.92%, specificity: 75.00%, and accuracy: 73.68-76.32% for RCV50). We conclude that the new in vitro model using HCE-T cells is a good alternative evaluation model for the prediction of the eye irritation potential of chemicals.

The influence of alkane chain length on the skin irritation potential of 1,2‐alkanediols

Several studies have reported that 1,2‐alkanediols show increasing anti‐microbial activity as their alkane chain length increases. However, there are no reports on the influence of alkane chain length on the skin irritation potential of 1,2‐alkanediols. To investigate the influence of alkane chain length on the skin irritation potential of 1,2‐alkanediols. The objective and subjective (sensory) skin irritation potentials of five 1,2‐alkanediols – 1,2‐butanediol, 1,2‐pentanediol, 1,2‐hexanediol, 1,2‐octanediol and 1,2‐decanediol – were evaluated. We also estimated percutaneous absorption by measuring in vitro skin penetration using a Franz diffusion cell system. Like anti‐microbial activity, sensory irritation potential increased as alkane chain length increased, most likely due to increasing membrane interference and/or intrinsic toxicity of 1,2‐alkanediols. 1,2‐Hexanediol showed the lowest objective skin irritation potential, which increased when the alkane chain length decreased or increased. Furthermore, percutaneous absorption negatively correlated with the alkane chain length of 1,2‐alkanediols. These results show that a lower skin absorption potential is not indicative of a low skin irritation potential. Our results suggest that the factors and processes involved in skin irritation potential are complex and that skin irritation potential is influenced by intrinsic toxicity and the potential for penetration or integration in the lipid bilayer.

Ethnic differences in objective and subjective skin irritation response: an international study

Due to global marketing in the cosmetics industry, it is important to assess ethnic population susceptibility when evaluating the safety of cosmetic products or chemicals.

The New in vitro Oral Irritation Test Method for Toothpaste using YD-38 Oral Mucosal Cell Line

우리는 평생 동안 하루도 빠짐없이 치약과 같은 구강관리 제품들을 사용한다. 이와 같이 매일 입에 사용되는 제품의 안전성이 담보되어야 함은 매우 중요한 일이다. 이전까지 이루어진 동물시험이나 임상시험에서 치약 내 계면활성제 등에 의한 구강 자극이 유발될 수 있음이 알려져 있다. 하지만, 동물복지를 위하여 유럽 화장품 법안은 화장품과 그에 사용하는 원료에 대한 동물 시험을 금지했다. 그로 인해 여러 분야에서 동물을 대체하거나 동물의 사용을 줄일 수 있는 동물대체 시험법의 개발이 활발하게 이루어지고 있다. 하지만, 현재까지 구강 점막 독성을 측정할 수 있는 방법으로 임상시험과 동물시험이 있었으며, 최근에는 구강 점막 조직 모델이나 구강 세포들을 활용한 방법들이 연구되고 있다. 이번 연구의 목적은 구강관리 제품의 안전성을 확보할 수 있는 동물대체 시험법을 개발하는 것이다. 구강 세포주(YD-38 cell)를 활용해 불용성 물질을 포함한 치약에 대한 시험이 가능하도록 구강 점막 자극 시험법을 개발하였고, 이 시험법으로 이전에 이루어진 동물시험에서 자극유발원으로 알려진 물질에 의한 자극을 구별해낼 수 있었다. 또한, 유아와 어린이 치약의 자극 수준이 일반 성인 치약에 비해 낮음을 증명하였다. 이 결과를 바탕으로 동물을 사용하지 않고 인체에 대한 위해성을 줄일 수 있도록, 구강관리 제품의 구강 점막 자극 수준을 평가할 수 있는 이 시험법이 하나의 새로운 구강 자극 시험 방법으로 사용될 수 있으리라 사료된다. 【Through our entire life, oral care products such as toothpaste are used. Thus the safety of oral care products used every day to our mouth is very important. As the previous study in animal tests or clinical trials, surfactant in toothpaste may cause the oral irritation. However, EU cosmetics legislation prohibits animal testing of cosmetics and its ingredient for animal welfare. Therefore the development of alternative in vitro test has been actively performed to replace or reduce using the animal in many areas. However, the way to evaluate oral mucosal toxicity has been done using animal models or clinical trials from now on. Even more, the experiment with human oral 3D tissue or human oral cell line is used recently. The aim of this study is the development of oral mucosal irritation method without using animal for the safety of the oral care product. We developed in vitro test method for oral irritation by using human oral cell line (YD-38 cell) acceptable to toothpaste which contains insoluble material. By the results of this assay, we could discriminate toothpaste with or without irritating substance as same manner in animal studies reported previously. In addition, we confirmed that toothpaste for babies and children toothpaste irritated oral musoca lower than the general adult toothpaste. The present study suggest that this new in vitro method by using human oral cell line (YD-38 cell) could be used for evaluation of oral irritation without using animal.】