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Toxic Responses of the Skin
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
The Draize test has undergone modification over the years and there is dispute over its reliability. However, the test is a good predictor of strong irritants. The Draize test is often a legal requirement in the evaluation of potentially toxic chemicals. Because of public opposition to this type of testing, however, many new tests using cultured epidermal cells are being developed and validated to replace the Draize test.
Nanomedicines for Ocular NSAIDs: State-of-the-Art Update of the Safety on Drug Delivery
Published in Lajos P. Balogh, Nano-Enabled Medical Applications, 2020
Joana R. Campos, Joana Araújo, Elisabet Gonzalez-Mira, Maria A. Egea, Elena Sanchez-Lopez, Marta Espina, Selma B. Souto, Maria L. Garcia, Eliana B. Souto
Although nanomaterials offer several advantages helping to deliver the drug effectively at the site of action, their toxicity profile is of great concern. Thereby in vivo toxicity studies of formulated nanomaterials are an important parameter to be considered. For any delivery system to be clinically adoptable, it is desirable that they should be safe, tolerable, non-irritant, and efficacious. Their concentration should be estimated carefully as very high concentration may cause irritation and corneal damage. Ionic surfactants are toxic while non-ionic ones can be used but with proper screening of suitable concentration required [221, 222]. Suitable animal model and toxicity tests are mandatory to evaluate the nanotoxicity. Draize test implemented by US FDA in 1940 is used for the prediction of toxicity considering rabbit eye. Rabbit is a suitable animal model to perform the toxicity study, because its eye is more sensitive and susceptible for ONS [223]. However, it suffers from many drawbacks, such as that it takes large amount of time to give the results, high dose requirement and most importantly over prediction of human responses. To circumvent the disadvantages of Draize test several strategies have been demonstrated, such as Bovine Cornea Opacity Permeability assay (very fast method, gives results of permeability in 24 h), Low-volume eye-irritation test (less dose required; 0.01 ml/0.01 g), and ocular organotypic models (able to retain normal physiology of enucleated eye or cornea) [24]. In our laboratory, it was designed and developed a corneal device to study possible modifications in the corneal structures after application of nanomedicines or free drugs to the eye [224]. The habitual conditions for the permeation studies were modified to reproduce the behaviour when eye drops are administered to the eye, and for this reason, a new tetra-compartmental pharmacokinetic model was developed. In order to determine possible modifications of the corneal structures after the permeation studies, these corneas can be submitted to scanning microscopy.
In silico prediction of the full United Nations Globally Harmonized System eye irritation categories of liquid chemicals by IATA-like bottom-up approach of random forest method
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Yeonsoo Kang, Boram Jeong, Doo-Hyeon Lim, Donghwan Lee, Kyung-Min Lim
According to the United Nations (UN) Globally Harmonized System (GHS), eye irritation refers to the production of changes in the eye following the application of a test chemical to the anterior surface of the eye (UN 2019). In vivo Draize rabbit eye irritation tests were used as a standard eye irritation test which uses a visual scoring system that grades the severity of irritation based upon external effects to the cornea, iris, and conjunctiva and then the number of days until effects are resolved (OECD 2017). Based upon these parameters, eye irritation potential of chemicals is classified into three categories; Not classified (No category), Category 2 (reversible irritation), and Category 1 (irreversible irritation or extreme damage) (Lebrun et al. 2019). However, in vivo Draize test have been criticized for lack of reproducibility, and over-prediction of eye irritation potential in human and animal welfare issues due to the brutal test procedure (Lotz 2016; Secchi and Deligianni 2006).