Reaction mass of rel-{(1R,2S)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl}methanol and rel-{(1S,2R)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl}methanol

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020

Reliability:

1 (reliable without restriction)

Data source

Reference

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

GLP compliance:

yes

Remarks:

See statement of conmpliance in study report < IN VITRO SKIN CORROSION ASSAYUSING THE EPIDERMTM SKIN MODEL (EPI-200): 3- AND 60-MINUTE EXPOSURE PROTOCOL >

Test material

Test material information

1

Reference substance name:

[(1R,2S)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1R,2S)-1-methyl-2-[(2S)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1S,2R)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1S,2R)-1-methyl-2-[(2S)-5-methylhex-4-en-2-yl]cyclopropyl]methanol

EC Number:

942-597-9

Cas Number:

1655500-83-6

Molecular formula:

C12H22O

IUPAC Name:

[(1R,2S)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1R,2S)-1-methyl-2-[(2S)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1S,2R)-1-methyl-2-[(2R)-5-methylhex-4-en-2-yl]cyclopropyl]methanol; [(1S,2R)-1-methyl-2-[(2S)-5-methylhex-4-en-2-yl]cyclopropyl]methanol

Specific details on test material used for the study:

GR-50-1408 is the Givaudan identification code which was employed for ROSYFOLIA during the early, developmental and testing period.

In vitro test system

Test system:

human skin model

Details on animal used as source of test system:

N/A - in-vtiro study

Details on test system:

The EpiDerm™ Skin Model (MatTek Corporation, MA, USA) was used to assess the potential skin corrosivity of the test article. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) conversion assay, which measures the NAD(P)H-dependent microsomal enzyme reduction of MTT (and to a lesser extent, the succinate dehydrogenase reduction of MTT) to a blue formazan precipitate, was used to assess cellular metabolism after test article exposure1. The protocol is consistent with the OECD Test Guideline 431 “In Vitro Skin Corrosion: Human Skin Model Test”

The EpiDerm™ Model (EPI-200) (MatTek Corporation, Ashland, USA) consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multi-layered, highly differentiated model of the human epidermis. It consists of basal, spinouts and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in-vivo. The model incorporates several features which make it advantageous in the study of potential dermal corrosively. Firstly, the test system uses a serum-free medium which eliminates the possibility of serum protein and test article interaction (Shopsis and Eng. 1988). Secondly, the target cells are epitherlial, derived from human skin (Cannot et al., 1994). Third, since the tissue has a functional stratum corneum, the test materials are applied directly to the tissue surface, at air interface, so that undiluted and/or end use dilutions can be tested directly (Harbell et al., 1994).

Test animals

Species:

other: N/A in-vitro study

Strain:

other: EpiDerm™ Skin Model

Test system

Type of coverage:

other: apical side of the tissue

Preparation of test site:

other: stratum corneum

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

The test article was administered to the test system without dilution (neat).

Details on study design:

The experimental design of this study consists of the determination of the direct MTT reduction potential, assessment of colorant potential, a pH determination, if possible, and a definitive corrosion assay. The in-vitro skin corrosion assay is used to determine the potential skin corrosively of test substances. The method consists of exposing stratum corneum surface (apical side) of the tissue to the test substance. After a 3- or 60minute exposure (2 tissues per exposure), the test substance is removed from the tissue by rinsing with calcium and magnesium-free Dulbecco’s phosphate buffered saline (CMF-DPBS). The rinsed tissue is then incubated for 3 ± 0.1 hours in an MTT dye solution to determine the degree of cytotoxicity (cell death) caused by exposure to the test substance. Viable cells reduce the yellow, soluble oxidised form of the MTT to the blue-black insoluble from. The reduced dye is extracted from the tissue with isopropanol and the amount of reduced dye is determined spectrophotometrically. The relative viability of the treated tissues is calculated relative to the negative control viability. Test substances that reduce tissue viability to <50%, after a 3-minute exposure, are classified corrosive by this method. In addition, test substances which result in tissue viability ≥50% after a 3-minute exposure and <15% after a 60-minute exposure are also classified corrosive. Test substances which result in tissue viability ≥50% after a 3-minute exposure and ≥15% after a 60-minute exposure are classified non-corrosive.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60/3 minutes

Value:

ca. 104.67 - ca. 120.52

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

no indication of corrosion

Other effects / acceptance of results:

The assay was accepted since:
1. the positive control resulted in a corrosive classification (i.e., < 50% cell viability compared to negative controls, after a 3-minute exposure and/or < 15% cell viability compared to negative controls after a 60-minute exposure)
2. the mean OD550 value of the negative control tissues was ≥ 0.8 and ≤ 2.8. The mean OD550 value of the tissues treated with the negative control at 3- and 60-minutes was 1.790 for the 60 minute exposure and 1.598 for the 3 minute exposure.
3. In the range of 20 to 100% viability, the Coefficient of Variation (CV) between 2 identically treated replicates of the negative and positive control per each exposure time was ≤ 30%.

Any other information on results incl. tables

Sponsor's Designation	Conc	Exposure time			% viability	Prediction	Subcategory	pH
Positive Control	NA	60 mins/3 mins			9.04/18.06	Corrosive	1A	NA
Rosyfolia	Neat	60 mins/3 mins			104.67/120.52	Non-corrosive	NA	5.0

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

According to the prediction model presented in the attached study report, the test article was predicted to be non-corrosive.

Executive summary:

The potential of rosyfolia to be corrosive was evaluated in EpiDerm tissue using a protocol consistent with OECD TG 431 In vitro skin corrosion: reconstructed human epidermis (RHE) test method. The apical side of the EpiDerm tissues were exposed to rosyfolia and after 3 or 60minute exposures (2 tissues/exposure) the test substance was removed from the tissue and the tissue incubated for 3 hrs in MTT dye solution to determine the degree of cytotoxicity caused by the test substance. The relative viability of the treated tissues is calculated relative to the negative control viability. Test substances that results in tissue viabililty of greater than or equal to 50% after 3 minute of exposure and 15% after a 60 minute exposure are classified as non-corrosive. The results showed that the viability was greater 50% at 3 minutes and well over 15% at 60 minutes. Based on the results of this test, rosyfolia is not considered corrosive.