Irritation Analysis

Human epidermis tissue consists of 5 main layers, from the most basal to the most superficial part: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The outermost epidermis has a flat structure consisting mainly of keratinocytes. This layer, consisting of cornified keratinocytes, is a barrier against substances that have the potential to cause irritation, and the keratinocytes they contain play important roles in the immune surveillance of the epidermis. Naturally, the induction of the inflammatory cascade in skin irritation begins in the uppermost layer, which is the first place where the cosmetic, biocidal or raw chemical penetrates.

In vitro Skin irritation testing (SIT) systems represent the biochemical and physiological properties of the human epidermis. It is performed with structured Human Epidermis (RhE) models.

The EpiDermTM SIT (EPI-200) protocol, accepted in the OECD 439 Testing Directive on the Testing of Chemicals, is performed with high precision. This model has been patented and proven by the ECVAM Scientific Advisory Committee (ESAC) as an In vitro 3D model system for testing chemical, pharmaceutical and skin care products. Irritation Test is required to be tested for type 1-11 biocidal products and cosmetic products that come into direct contact with the skin.

The test protocol consists of exposing conditioned tissues to the positive control and negative control and test chemical for 1 hour and removing them after the exposure period. It ends with the determination of NAD(P)H-dependent cellular oxidoreductase enzyme activity and the metabolic activity of the cells using the colorimetric method, based on the MTT assay method. In summary, determining the skin irritation potential of the product to be tested is based on tissue viability and should be carried out by experts in the field in accredited and authorized laboratories.