Cosmetic ingredients

Acute toxicity tests evaluate the toxic potential of human cell culture. The method provides information on the hazardous properties and allows the substance to be classified for acute toxicity according to the Globally Harmonised System of classification and labeling of chemicals.

Techniques:

• Neutral red absorption
• Flow cytometry -apoptosis and late death
• MTT assay
• IC50 and LD50

Reference: OECD TG 129; OECD TG 420; OECD TG 423; OECD TG 425.

OECD 487

Genotoxicity tests are designed to detect compounds that induce genetic damage by different mechanisms.

• Fluorescence microscopy
• Flow cytometry

Evaluation of the potential of skin inflammation of the product. Skin inflammation safety testing and risk assessment for products and there ingredients are critical requirements before marketing.

Technique:

• Flow cytometry
• Gene expression (RT-qPCR)

Reference: Curr. Protoc. 2021 Mar;1(3):e72. DOI: 10.1002/cpz1.72.

OECD 439

Evaluation of the skin irritation potential in vitro after topical application of the investigational product in a three-dimensional model of RhE, composed of untransformed epidermal keratinocytes of human origin, being evaluated the cell viability by MTT.

OECD437

To evaluate irritation in rabbit corneal cell culture (SIRC) with two concentrations of the test substance (5% and 0.05%). After a brief exposure time a cell viability assay (MTT Test) is performed to measure the viability of the cells.

OECD442E

Skin sensitisation refers to an allergic response following skin contact with the tested chemical, as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS).

Technique: Flow Cytometry.

Identification of agents that cause structural chromosome aberrations in cultured mammalian somatic cells. Structural aberrations may be of two types: chromosome or chromatid.

Reference: OECD 473 and EC B.10 – “Chromosome aberration test in human cells”.

Evaluation of photo-cytotoxicity by the relative reduction in viability of cells exposed to the chemical in the presence versus absence of light.

Reference: OECD TG 432 – In Vitro Phototoxicity Test 3T3 NRU.

Microbiome evaluation test after application of a test cosmetic for 28 days, in three volunteers aged 18-45 years. The test formulation will be applied twice a day on the skin region (to be defined) of the volunteers. On day 0 and day 28, swab samples from the surface of the skin in the designated area will be collected. 16S rRNA sequencing analysis will identify the microbial diversity of the skin.

Reference: LEE, Hyo Jung; JEONG, Sang Eun; LEE, Soyoun; KIM, Sungwoo; HAN,Hyuntak; JEON,Che Ok. Effects of cosmetics on the skin microbiome of facial cheeks with different hydration levels. Microbiologyope
n, [S.L.], v. 7, n. 2, p. 00557-00561, 29 Nov. 2017.
Wiley.

Evaluation of developmental and reproductive toxicity. Provide information concerning the effects of prenatal exposure on the developing organism.

Reference: OECD 414 e EC B.31. 

The test chemical is applied topically to a minimum of two three-dimensional Reconstructed human Cornea-like Epithelium (RhCE) tissue constructs and tissue viability is measured following exposure and a post-treatment incubation period. RhCE tissue viability is classically measured by enzymatic conversion of the vital dye MTT by the viable cells of the tissue into a blue MTT formazan salt that is quantitatively measured after extraction from tissues.

Test System: SkinEthicTM HCE / Human Corneal Epithelium.

Reference: OECD 492 – Reconstructed human Cornea-like Epithelium (RhCE) test method for identifying chemicals not requiring classification and labelling for eye irritation or serious eye damage. 

Relate concentration or dose to the observed toxicity and to understand its mechanism of toxicity.

Reference: OECD 417 and EC B. 36.

OECD 471 – Bacterial Reverse Mutation Assay

Bacterial cells are exposed to test chemical in the presence and absence of metabolic activation, either by plate incorporation or by pre-incubation prior to plating out. Mutations are determined by scoring bacterial growth (revertant colonies) on selective agar plates lacking the essential amino acid.

Five different analysable concentrations of the test substance will be used.

The recommended combination of strains is:

• S. typhimurium TA1535;
• S. typhimurium TA1537;
• S. typhimurium TA98;
• S. typhimurium TA100;
• S. typhimurium TA102 or E. coli WP2 uvrA (pKM101)r.