Decahydro-1,1,7-trimethyl-3a,7-methano-3aH-cyclopentacyclooct-3-yl formate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation / corrosion, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan - March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Decahydro-1,1,7-trimethyl-3a,7-methano-3aH-cyclopentacyclooct-3-yl formate

EC Number:

261-118-8

EC Name:

Decahydro-1,1,7-trimethyl-3a,7-methano-3aH-cyclopentacyclooct-3-yl formate

Cas Number:

58096-47-2

Molecular formula:

C16H26O2

IUPAC Name:

decahydro-1,1,7-trimethyl-3a,7-methano-3aH-cyclopentacyclooct-3-yl formate

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

other: Adult human-derived epidermal keratinocytes

Cell type:

non-transformed keratinocytes

Cell source:

other: Not specified

Source strain:

not specified

Justification for test system used:

EPISKIN Standard Model™ is a 0.38 cm2 reconstituted human epidermis model. Adult human-derived epidermal keratinocytes are seeded on a dermal substitute consisting of a collagen type I matrix coated with type IV collagen.

Vehicle:

unchanged (no vehicle)

Details on test system:

Procedure for application of test item (3 minutes treatment)
• 50 µL of the test item was applied evenly to the epidermal surface.
• Added 50 µL NaCl for negative control
• After application, plate containing the treated epidermis was closed with lid and incubated for 3 minutes at 37 °C and 5% CO2.
Procedure for application of test item (60 minutes treatment)
• 50 µL of the test item was applied evenly to the epidermal surface.
• Added 50 µL NaCl for negative control
• After application, plate containing the treated epidermis was closed with lid and incubated for 60 minutes at 37 °C and 5% CO2.
Procedure for application of test item (240 minutes treatment)
• 50 µL of the test item was applied evenly to the epidermal surface
• .Added 50 µL NaCl for negative control; 50 µL glacial acetic acid for positive control
• After application, plate containing the treated epidermis was closed with lid and incubated for 240 minutes at 37 °C and 5% CO2.
Approximately 1 minute interval between each tissue application was followed for all the time points of application

Control samples:

yes, concurrent negative control

Amount/concentration applied:

50 µL NaCl

Duration of treatment / exposure:

3 minutes, 60 minutes and 240 minutes exposure

Duration of post-treatment incubation (if applicable):

Incubated for 3, 60 and 240 minutes at 37 °C and 5% CO2.

Number of replicates:

Two

Test animals

Species:

other: Reconstituted Human epidermis (RHE)

Strain:

not specified

Test system

Type of coverage:

not specified

Preparation of test site:

not specified

Vehicle:

unchanged (no vehicle)

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3,60 and 240 minutes

Value:

> 35

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Any other information on results incl. tables

Table: Percent tissue viability

	% Viability
	3 minutes application		60 minutes application		240 minutes application
Replicate	NC	Test item	NC	Test item	NC	PC	Test item
Rep 1	96.082	90.231	106.941	99.510	110.003	2.131	98.522
Rep 2	103.918	83.821	93.059	85.397	89.997	8.250	98.041
Mean	100.0	87.03	100.0	92.45	100.0	5.19	98.28
SD	5.540	4.533	9.816	9.979	14.147	4.327	0.340

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results, the % viability of the test item DECAHYDRO-1, 1, 7-TRIMETHYL-3A, 7-METHANO-3AH-CYCLOPENTACYCLOOCT-3-YL FORMATE was greater than 35% of the negative control. Hence under the conditions of the study the test item was found to be ‘Non-corrosive’ to skin in accordance with UN GHS as specified in the OECD Guideline for the Testing of Chemicals.

Executive summary:

Test item, Decahydro-1,1,7-trimethyl-3a,7-methano-3aH-cyclopentacyclooct-3-yl formate was applied topically to the EPISKIN^TMepidermal model (two epidermis units were used per each test item and negative controls) for three exposure periods viz., 3 minutes, 60 minutes and 240 minutes, additionally two epidermis units were used for positive control for the exposure period of 240 minutes. Exposure to the test item was terminated by rinsing with Dulbecco’s phosphate buffered saline (DPBS). The viability was assessed by incubating the tissues for 3 hours with MTT solution in a 12 well plate (0.3 mg/ml in assay medium; 2 ml per well). The precipitated formazan was then extracted using acidified isopropanol (0.5 ml) for 4 hours at room temperature and quantified spectrophotometrically at 560 nm using 96 well plates (200 μl/well).

Glacial acetic acid and Sodium chloride (9.0 g/ L) treated epidermis were used as positive (PC) and negative controls (NC) respectively. For each treated tissue, the viability was expressed as the % of the negative control tissues (mean). 

 

3 minutes application:

The negative controls mean OD was found to be 0.983, which is well within the acceptability range (0.6 to 1.5). The variation within the replicates of negative control and test item was found to be lesser than 30%. The % viability of the test item was 87.03% and it was greater than 35% of the negative control. Hence no corrosive reaction observed with test item at 3 minutes application period.

 

60 minutes application:

The negative controls mean OD was found to be 0.868, which is well within the acceptability range (0.6 to 1.5). The variation within the replicates of negative control and test item was found to be lesser than 30%. The % viability of the test item was 92.45 % and it was greater than 35% of the negative control. Hence no corrosive reaction observed with test item at 60 minutes application period

 

240 minutes application:

The negative controls mean OD was found to be 0.727, which is well within the acceptability range (0.6 to 1.5). The variation within the replicates of negative control and test item was found to be lesser than 30%. The % viability of the test item was 98.28% and it was greater than 35% of the negative control. Hence no corrosive reaction observed with test item at 240 minutes application period.

The % viability of the positive control was, 5.191 % at 240 minutes application time and it was lesser than 50% of the respective negative controls, which reflects the corrosive nature of positive control and the sensitivity of the tissues used in the study.

The % viability of test item at the application periods of 3 minutes, 60 minutes and 240 minutes showed greater than 35% mean tissue viability in terms of % negative control. Hence the test item is not categorized as corrosive 1A, 1B and 1C.

The % viability of test item at the application period of 240 minutes showed greater than 35% mean tissue viability in terms of % negative control. Hence the test item is categorized as‘Non-corrosive’