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Endpoint summary

Description of key information

Two in vitro/ex vivo studies were conducted with MDP to determine its skin and eye irritation/corrosion potential. The results of the studies were:

When tested according to OECD 431: Corrosive (GHS Category 1) to the skin.

When tested according to OECD 437: Corrosive (GHS Category 1) to the eye.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

No data

Deviations:

no

Remarks:

No deviations ocurred that negatively impacted the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: 3M Company,
- Purity, including information on contaminants, isomers, etc.: Reaction product as described in the general information section.

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: NA
- Stability in the medium, i.e. sensitivity of the test material to hydrolysis and/or photolysis: No data
- Solubility and stability of the test material in the solvent/vehicle and the exposure medium: No data
- Reactivity of the test material with the incubation material used (e.g. plastic ware): No data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING : None, dosed neat.

Test system:

human skin model

Source species:

human

Cell type:

other: Three-dimensional human epidermis model - EpiDerm

Cell source:

other: No data

Details on animal used as source of test system:

SOURCE ANIMAL
- Source: Human
- Sex: No data
- Age at study initiation (in days): No data
- Weight at study initiation: No data
- Housing: No data
- Diet (e.g. ad libitum): No data
- Water (e.g. ad libitum): No data
- Acclimation period: No data

Justification for test system used:

EpiDerm is recommended per OECD 431 guideline.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: MatTek EpiDerm
- Tissue batch number(s): 27170 Kit C
- Production date: No data
- Shipping date: No data
- Delivery date: 24 Oct 2017
- Date of initiation of testing: 25 Oct 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 C
- Temperature of post-treatment incubation (if applicable): 37 C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 2 washing steps, volume not reported.
- Observable damage in the tissue due to washing: None
- Modifications to validated SOP: None

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 300 uL at 1 mg/mL MTT
- Incubation time: 3 hours
- Spectrophotometer: uQuant Plate Reader, Bio-Tek Instruments
- Wavelength: 540 nm
- Filter: No data
- Filter bandwidth: No data
- Linear OD range of spectrophotometer: No data

NUMBER OF REPLICATE TISSUES: 3 per group (test, negative control, positive control).

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE : No data

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1 experiment in triplicate.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 uL
- Concentration (if solution): Neat

VEHICLE : None

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 uL
- Concentration (if solution): NA

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 uL
- Concentration (if solution): 8.0 N

Duration of treatment / exposure:

3 and 60 minutes

Duration of post-treatment incubation (if applicable):

3 hour incubation with MTT post-exposure

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 Minute Exposure Mean

Value:

80.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 Minute Exposure Mean

Value:

4.7

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: None
- Direct-MTT reduction: None
- Colour interference with MTT: None

DEMONSTRATION OF TECHNICAL PROFICIENCY: The laboratory has demonstrated proficiency in running OECD 431 with EpiDerm tissues.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes, the mean OD of the negative control tissues was 2.246 at 3 minutes and 2.092 at 60 minutes, which met the acceptance criterion (OD greater than or equal to 0.8).
- Acceptance criteria met for positive control: Yes, the mean relative tissue viability of the 60-minute positive control was 2.4%, which met the acceptance criterion (>15%).
- Acceptance criteria met for variability between replicate measurements: Yes, viability differences between the two identically treated tissues in all samples and controls at 3 minutes were 2.9% to 7.7%. Viability differences between the two identically treated tissues at 60 minutes were 0.1 % to 1.3%. Inter-tissue viability differences at both time points met the acceptance criterion (>30%)
- Range of historical values if different from the ones specified in the test guideline: Per OECD 431.

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

Based on the results of the study (3 minute viability 4.7%, 60 minute viability 80.6%), MDP is corrosive when tested according to OECD 431 with EpiDerm tissues.

Executive summary:

The skin corrosion potential of MDP was evaluated in MatTek EpiDerm tissues. The study was conducted according to OECD 431 in compliance with OECD GLP. EpiDerm tissues were exposed (N=3) to 50 uL of the test article (MDP), negative control (tissue culture water), and positive control (potassium hydroxide, 8.0 N) for 3 and 60 minutes. Following exposure the tissues were washed and incubated with MTT to determine tissue viability. Relative viability was 80.6% after a 3 minute exposure and 4.7% after a 60 minute exposure. Based on the results of the study (3 minute viability 4.7%, 60 minute viability 80.6%), MDP is corrosive when tested according to OECD 431 with EpiDerm tissues.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Version / remarks:

No data

Deviations:

no

Remarks:

No deviations ocurred that negatively impacted the integrity of the study.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material:
3M Company,
- Purity, including information on contaminants, isomers, etc.:
Reaction product as described in the general information section.

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
At room temperature
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage:
NA
- Stability in the medium, i.e. sensitivity of the test material to hydrolysis and/or photolysis:
No data
- Solubility and stability of the test material in the solvent/vehicle and the exposure medium:
No data
- Reactivity of the test material with the incubation material used (e.g. plastic ware):
No data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
: None, dosed neat.

Species:

cattle

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Spear Products
- Number of animals: No data
- Characteristics of donor animals (e.g. age, sex, weight): No data
- Storage, temperature and transport conditions of ocular tissue: Eyes were transported under refrigeration.
- Time interval prior to initiating testing: The eyes were dosed the same day as they arrived.
- Indication of any existing defects or lesions in ocular tissue samples: Only eyes free of defects were used.
- Indication of any antibiotics used: Penicillin-streptomycin was used.
- Selection and preparation of corneas: The eyes were examined prior to use on the day of dosing. Any eye with a cornea exhibiting evidence of vascularization, pigmentation, opacity or scratches was discarded. Corneas from eyes that were free of defects were dissected from the surrounding tissues. A 2-3 mm rim of sclera was left attached to each cornea. The corneas were then placed in a container of fresh HBSS.
- Quality check of the isolated corneas: The dissected corneas were mounted in specially designed holders that were separated into anterior and posterior chambers and filled separately. Each cornea was mounted allowing the epithelium of the cornea to project into the anterior chamber. The posterior chamber was filled with MEM solution ensuring contact with the endothelium. The anterior chamber was filled with MEM solution, ensuring contact with the epithelium. Each cornea was visually inspected again to ensure there were no defects. The entire holder was incubated at 32 (±1)°C and allowed to equilibrate for at least one hour, but not longer than two hours. A pre-exposure determination of opacity was made for each cornea by measuring each against the blank supplied by the opacitometer. Any cornea with a value greater than 7 units was discarded.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.75 mL
- Concentration (if solution): neat

VEHICLE: None

Duration of treatment / exposure:

10 minutes

Duration of post- treatment incubation (in vitro):

2 hours

Number of animals or in vitro replicates:

3 ex vivo replicates

Details on study design:

NUMBER OF REPLICATES : 3

NEGATIVE CONTROL USED : Minimal Essential Media

SOLVENT CONTROL USED: NA

POSITIVE CONTROL USED : 100% Ethanol

APPLICATION DOSE AND EXPOSURE TIME : 0.75 mL for 10 minutes

TREATMENT METHOD: Closed chamber

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: At least 2

- POST-EXPOSURE INCUBATION: 2 hours

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: A
measurement of opacity was taken with each treated cornea compared to the blank supplied with the OP-KIT. This reading was used in the final IVIS calculations.
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of UV spectrophotometry (OD490)


SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA: Per OECD 437

Irritation parameter:

cornea opacity score

Run / experiment:

Mean

Value:

82.7

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

fluorescein leakage

Run / experiment:

Mean (OD 490 nm)

Value:

0.264

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

other: Corrected Mean Optical Density

Remarks:

Corrected Mean Optical Density

Run / experiment:

Mean

Value:

0.241

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean

Value:

86.28

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

IVIS = 0.35

Positive controls validity:

valid

Remarks:

IVIS = 25.83

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: None

DEMONSTRATION OF TECHNICAL PROFICIENCY: The lab is proficient in running OECD 437.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: No data
- Acceptance criteria met for positive control: The ethanol positive control IVIS was 25.83, which fell within the acceptance range of 16.96 - 37.00
(± 2 standard deviations of the historical mean).
- Range of historical values if different from the ones specified in the test guideline: Per OECD 437.

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Based on the results of the study (IVIS = 86.28), MDP is corrosive (GHS Category 1) in the Bovine Corneal Opacity and Permeability Test (BCOP).

Executive summary:

The eye irritancy/corrosion potential of MDP was evaluated in the Bovine Corneal Opacity and Permeability Test (BCOP). The study was conducted according to OECD 437 in compliance with OECD GLP. Corneas (N=3) were exposed to 0.75 mL of the test article (MDP), negative control (MEM), or positive control (100% Ethanol) for 10 minutes. Corneal opacity was determined at 10 minutes and 2 hours post-exposure. Corneal permeability was determined following a 90 minute incubation with fluorescein on the anterior side of each cornea. The amount of dye that passed through the cornea was measured by spectrophotometer at 490 nm. Exposure to MDP resulted in a mean corneal opacity score of 82.7, mean corneal permeability of 0.264 and mean corrected optical density of 0.241, resulting in an In Vitro Irritancy Score (IVIS) of 86.28. Based on the results of the study (IVIS = 86.28), MDP is corrosive (GHS Category 1) in the Bovine Corneal Opacity and Permeability Test (BCOP).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Justification for classification or non-classification

Based on the results of the studies, MDP meets the GHS Classification Criteria for Category 1 (Corrosive) for both eye and skin.