ICH S7B and E14 guidelines, which were first released in 2005, are focused on hERG blockade and QT prolongation by drugs. However, cumulated evidences on some pitfalls of the guidelines resulted in the initiation of the comprehensive in vitro proarrhythmia assay (CiPA) project. Results of the CiPA are expected to change global regulatory environment on the cardiac safety of drugs. In this study, we reproduced two components of the CiPA to assess the performance of their in silico biomarker using in vitro ion channel assay data. The process to obtain qNET, a biomarker proposed by CiPA, was fully reproduced through in vitro and in silico studies in selected three drugs (verapamil, ranolazine, moxifloxacin). Throughout the reproducing research, we obtained many practical experiences not included in publications by the CiPA. For further understanding of this new regulatory paradigm, clinical ECG in human and another in silico method are to be performed.
The cytokinesis-block micronucleus cytome assay is a measuring of DNA damage in once-divided binucleated (BN) cells scoring micronuclei (MNi) that are widely used as biomarkers of cancer risk in humans on drugs or chemicals. However, this assay is still challenging due to the speed of sample processing and the toxicity of organic chemicals on researcher. To address these problems, we developed a new and convenient method for the micronucleus cytome assay. This method by DAPI stained micronucleus detection is non-toxic to the researcher and is being simplified because it does not require the use of methanol and acetic acid for fixing cell. Especially, three dimensional imaging of nucleus by formalin fixed DAPI staining provides more detailed information for testing the effects of chemical and bio-materials, compared to the classic method.
In this study, we examine the spatial distribution of the TANNylated GFPs by advanced cytokinesis-block micronucleus (ACBMN) assay. The TANNylated GFPs were precisely observed in the inner nucleus by three dimensional imaging, whereas GFPs were not detected in any regions of cells. This micronucleus assay can readily be used in genetic based toxicity and efficacy assay to the various bio-chemicals and pharmaceutical evaluation.
Although fragrance-free cosmetics are increasing in recent years, fragrance is still an important element of cosmetics. The phototoxicity of fragrance used in cosmetics is tested to confirm the safety before used. Because fragrances are mixtures of various aromatic compounds and exact composition of them are not disclosed by the fragrance company, it is difficult to analyze and/or presume the cause of phototoxicity.
Therefore, it is important to use the test method having good applicability to various mixture and high reliability of results. In this study, we tried to establish an appropriate ITS approach to improve the reliability of the cosmetic fragrance toxicity test. Three animal alternatives, 3T3 neutral red uptake phototoxicity assay (OECD TG 432), Reactive oxygen species assay, Molar absorption (extinction) coefficient (MEC) measurement test were performed and coincidence rates among tests were compared. As a result, the application of the ITS approach wasn’t suitable for fragrances due to the lack of harmonization of the three test methods and different positive rates. 3T3 neutral red uptake phototoxicity assay presumed to be most suitable for the evaluation of the phototoxicity of fragrance in terms of safety. Reactive oxygen species assay and MEC measurement test were thought to be available to reconfirm the results of 3T3 neutral red uptake phototoxicity assay.
The objective of this study is to investigate the utility of reconstructed human corneal epithelium model(SkinEthic TM , HCE) as an alternative method to eye irritation test.
We confirmed the pre-check test method for eye irritation test through condition setting of production for freeze-killed epidermis, possible direct MTT reduction with test substances, and colorant properties in test chemicals. And, we conducted eye irritation test using 8 chemicals listed in the proficiency test of the OECD test guideline 492. Summarizing the results above of assessment, it was confirmed that the SkinEthic TM HCE proves that it is so efficient and trustworthy enough to replace the eye irritation test.
Taken together, the results indicated that the SkinEthic TM HCE proposed by OECD test guideline 492 is expected to become a well-established method in Korea.