Soaps and Detergents: Alternatives to Animal Eye Irritation Tests

Abstract

An extensive computer search was conducted, and a comprehensive overview of the current status of alternatives to animal eye irritation tests was obtained. A search of Medline and Toxline databases (1988 to present) was supplemented with references from sources regarding in vitro eye irritation. Particular attention was paid to soap and detergent products and related ingredients. Eighty-five references are included in the review; the in vitro assays are categorized, and their predictive values for assessing acute ocular irritation are evaluated and compared with the Draize rabbit eye irritation assay and with each other. The present review shows that the increased activity of scientists from academia, industry, and regulatory agencies has resulted in substantial progress in developing alternative in vitro procedures and that a number of large, interlaboratory evaluations and international workshops have assisted in the selection process. However, none of these methodologies has obtained acceptance for regulatory classification purposes. Conclusions drawn from this review include that (a) no single in vitro assay is considered capable of replacing the Draize eye irritation test; (b) the chorioallantoic membrane vascular assay (CAMVA) or the hen egg test-chorioallantoic membrane test (HET-CAM), the chicken or bovine enucleated eye test, the neutral red and plasminogen activation assays for cytotoxicity, and the silicon microphysiometer appear to have the greatest potential as screening tools for eye irritation: and (c) choosing a specific assay or series of assays will depend on the type of agent tested and the impact of false-negative or falsepositive results. New assays will continue to be developed and should be included in future evaluations, when sufficient data are available.

In Vitro Models in Biocompatibility Assessment for Biomedical-Grade Chitosan Derivatives in Wound Management

“…However, our focus here is on submerged monolayer epidermal keratinocyte culture models. The primary reason for this focus is a key concept in support of incorporating keratinocyte culture models into a battery of cutaneous toxicity tests, namely keratinocytes make up the bulk (greater than 90%) of epidermal tissue mass [ 48 ], and viable keratinocytes (not exposed directly to air) participate in the conversion of environmental stimuli into biological signals that activate the inflammatory and hyper-proliferative responses of the skin [ 49 ]. Therefore, submerged cultures of epidermal keratinocytes model a major component of the target epidermal tissue, allowing an assessment of the effects of drugs or chemicals on the skin.…”

Predictive Value of in Vitro Model Systems in Toxicology

“…Third, interpretation of results with keratinocyte cultures is limited to assuming a lack of involvement of other cell types that would be present in vivo, such as fibroblasts, melanocytes, and Langerhans cells. Fourth, testing for powders, gels, creams, other complex topical formulations, and insoluble material is inherently difficult, if not impossible, in cell culture models (12). Finally, any or all of these assumptions may be more or less important when assessing the in vitro toxicity of specific chemical or therapeutic classes of compounds; that is, the physicochemical properties of individual test compounds (13) and the relationship of in vitro exposure to the anticipated human skin exposure cannot be overlooked.…”

Validating and troubleshooting ocular in vitro toxicology tests

“…It also provides scoring that allows for relative categorization of severity for reversible effects such as mild, moderate, or severe irritants. Despite its scientific endurance in toxicity testing however (significant pain inflicted on the rabbits notwithstanding), the Draize eye test has been justifiably criticized for several shortcomings: its lack of reproducibility, its subjective nature of assessment, the variable interpretation of results, the high dose of test material used, and the over prediction of human response (Christian and Diener, 1996; Lordo et al , 1999; Ohno et al , 1999; Weil and Scala, 1971). …”