Sodium 4-morpholin-1-ylethylsulphonate

Endpoint summary

Description of key information

In an experimental study according to OECD test guideline 439 under GLP conditions, the test substance did not reduce cell viability. Therefore, it is considered to be not skin irritating.

In an experimental study according to OECD test guideline 438 under GLP conditions, the test substance scored into ICE Class I for corneal opacity and swelling and into ICE Class II for fluorescein retention. With the overall ICE score of 2xI and 1xII, the substance is classified as "No Category" for eye irritation according to the GHS classification system.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-06-29 to 2016-07-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

2015

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

2012

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

TISSUE
- Model used: EPISKIN(TM) Small Model (SM)
- Tissue batch number: 16-EKIN-026
- Date of initiation of testing: 29.06.2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation: 37 °C for 42 hours

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 25 mL PBS solution used to thoroughly rinse the tissue once
- 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: 2 mL of 0.3 mg/mL MTT per well
- Incubation time: 3 hours +/- 5 min
- Spectrophotometer: not specified
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS
- Morphology: well-differentiated epidermis consisting of a basal layer, several spinous and granular layers and a thick stratum corneum
- Contamination: absence of bacteria, fungus and mycoplasma

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE: no direct MTT interference

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA
- A test item is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1), if the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50 % of the negative control.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 10 mg (to moistened skin)

NEGATIVE CONTROL
- Amount applied: 10 µL

POSITIVE CONTROL
- Amount applied: 10 µL
- Concentration: 5 % aq.

Duration of treatment / exposure:

15 minutes

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

116

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100 %

Positive controls validity:

valid

Remarks:

18 %

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: no
- Direct-MTT reduction: No colour change was observed after three hours of incubation. The test material did not interact with the MTT, therefore additional controls and data calculations were not necessary. A false estimation of viability can be precluded.
- Colour interference with MTT: The test item showed no ability to become coloured in contact with water. The intrinsic colour of test item is white and therefore considered to be not able to significantly stain the tissues and lead false estimate of viability. Furthermore, the test item was completely removed from the epidermal surface at rinsing period. Additional controls and data calculations were not necessary. A false estimation of viability can be precluded.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: yes

Interpretation of results:

GHS criteria not met

Conclusions:

In an experimental study according to OECD TG 439 under GLP conditions, the test substance did not reduce cell viability. Therefore, it is considered not irritating to skin.

Executive summary:

A test according to OECD TG 439 has been performed to predict its irritation potential of the test item by measurement of its cytotoxic effect, as reflected in the MTT assay. Triplicates of the human skin model EPISKIN (Reconstructed Human Epidermis, SkinEthic Laboratories) were treated with test item and incubated for 15 minutes at room temperature. Exposure of the reconstructed human epidermis skin units with test item was terminated by rinsing with PBS 1x solution. Epidermis units were then incubated at 37 °C for 42 hours in an incubator with 5 % CO2. The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution at 37 °C in 5 % CO2 protected from light. The precipitated formazan was then extracted using acidified isopropanol and quantified spectrophotometrically.

SDS (5 % aq.) and 1×PBS treated epidermis (three units / positive and negative control) were used as positive and negative controls respectively. For each treated tissue viability was expressed as a percentage relative to negative control.

A test item is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1), if the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50 % of the negative control. In this in vitro skin irritation test using the EPISKIN model, the test item did not show significantly reduced cell viability in comparison to the negative control (mean value: 116 %). All obtained test item viability results were far above 50 % when compared to the viability values obtained from the negative control. Therefore the test item was considered to be non-irritant to skin.

Positive and negative controls showed the expected cell viability values within acceptable limits. The experiment was considered to be valid. The results obtained from this in vitro skin irritation test, using the EPISKIN model, indicated that the test item reveals no skin irritation potential under the utilised testing conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

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:

2016-06-21

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye 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:

2013

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU method B.48 (Isolated chicken eye test method for identifying occular corrosives and severe irritants)

Version / remarks:

2010

GLP compliance:

yes (incl. QA statement)

Species:

chicken

Strain:

other: ROSS 308

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): 30 mg per eye)

CONTROLS
- Amount(s) applied (volume or weight with unit): 30 mg imidazole; 30 µL NaCl (in saline)

Duration of treatment / exposure:

After 10 seconds the cornea surface was rinsed thoroughly with approx. 20 mL saline solution at ambient temperature

Observation period (in vivo):

30, 75, 120, 180 and 240 minutes after post-treatment rinse (minor variations +/- 5 minutes were considered acceptable)
Cornea thickness and opacity were measured at all time points. Flurescein retention was determined at baseline (t=0) and at 30 min.

Duration of post- treatment incubation (in vitro):

4 hours

Number of animals or in vitro replicates:

3 eyes (test substance and positive control)
1 eye (negative control)

Details on study design:

SELECTION AND PREPARATION OF ISOLATED EYES:
Head collection was performed by a slaughter house technician. Heads were removed immediately after sedation of the chickens (sedation was happened by electric current). The heads were transported to Toxi-Coop ZRT. at the earliest convenience for use approximately within 2 hours from collection. The ambient temperature was optimal (19.3 ºC to 20.2 ºC) during the transport. All eyes used in the assay were from the same groups of eyes collected on one specific day.
With the eyes still in the chicken heads, eyelids were carefully cut away with scissors from the chicken eyes. One small drop of fluorescein solution 2% (w/v) was applied onto the cornea surface for a few seconds and then rinsed off with 20 mL isotonic saline. The fluroescein-treated cornea was examined with a hand-held slit lamp or a slit lamp microscope. If the cornea was ingood condition, the eyeball was carefully removed from the orbit by holding the nictitating membrane with a surgical forceps, while cutting the eye muscles with bent scissors without cutting off the optical nerve too short. The procedure avoided pressure on the eye, which may lead to corneal opacity.Once removed from the orbit, the eye was placed onto damp paper and the nictitating membrane was cut away with other connective tissue. The prepared eyes were kept on the wet papers in a closed box to maintain the appropriate humidity.

EQUILIBRATION AND BASELINE RECORDINGS
The prepared eye was placed in a stell clamp with the cornea positioned vertically with the eye in the correct relative position (same position as in the chicken head), again avoiding too mucg pressure on the eye. Because of the relatively firm sclera of the chicken eyeball, only slight pressure was applied to fix the eye properly. The clamp was transferred to a chamber of the superfusion apparatus. The clamp holding the eye was positioned in such a way that the entire cornea was supplied with saline solution dripping from a stainless steel tube, at a rate of approx. 3 to 5 drops/min.The door of the chmber was closed, excpet for manipulations and examination, to maintain temperature and humidity.
Eyes selected for testing were again examined with the slit lamp microscope. Eyes with a high baseline flurescein staining (i.e. > 0.5) or corneal opacity score (i.e. > 0.5) were rejected.

NUMBER OF REPLICATES: 3

NEGATIVE CONTROL USED: NaCl in saline (9 g/L) (n=1)

SOLVENT CONTROL USED: not applicable

POSITIVE CONTROL USED: Imidazole (n=3)

APPLICATION DOSE AND EXPOSURE TIME: 0.03 g per eye for 10 seconds

OBSERVATION PERIOD: 4 hours

REMOVAL OF TEST SUBSTANCE
- Volume and washing procedure after exposure period: Thorough rinsing with approx. 20 mL saline solution at ambient temperature
- Indicate any deviation from test procedure in the Guideline: none

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: Opacity scores ranging from 0 (no opacity) to 4 (complete opacity; iris invisible) according to the test guideline were measured at all time points
- Damage to epithelium based on fluorescein retention: Fluorescein retention scores raning from 0 - 3 according to the test guideline were measured at 0 and 30 min.
- Swelling: measured with optical pachymeter on a slit-lamp microscope; slit-width setting: Cornea thickness was measured using the depth measauring device on the slit lamp microscope (Haag-Strei BQ 900) with the slit-width set at 9.5, i.e. 0.095mm.
- Macroscopic morphological damage to the surface: not applicable
- Others (e.g, histopathology): not performed

SCORING SYSTEM:
- Mean corneal swelling (%): acoording to TG
- Mean maximum opacity score: acoording to TG
- Mean fluorescein retention score at 30 minutes post-treatment: acoording to TG

DECISION CRITERIA: Decision criteria as indicated in the TG were used.

Irritation parameter:

percent corneal swelling

Run / experiment:

1 (240 min)

Value:

2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

2 %

Positive controls validity:

valid

Remarks:

30 %

Irritation parameter:

cornea opacity score

Run / experiment:

1 (240 min)

Value:

0.5

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.5

Positive controls validity:

valid

Remarks:

4.0

Irritation parameter:

fluorescein leakage

Run / experiment:

1 (240 min)

Value:

0.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

0.0

Positive controls validity:

valid

Remarks:

3.0

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: no

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes

Interpretation of results:

GHS criteria not met

Conclusions:

In an experimental study according to OECD TG 438 under GLP conditions, the test substance scored into ICE Class I for corneal opacity and swelling and into ICE Class II for flurescein retention. With the overall ICE score of 2xI and 1xII, the substance is classified as "No Category".

Executive summary:

A study was conducted according OECD TG 438. The purpose of this Isolated Chicken Eye Test (ICET) was to evaluate the potential ocular corrosivity and irritancy of the test item by its ability to induce toxicity in enucleated chicken eyes. This test identifies chemicals either inducing "serious eye damage" (category 1 of the Globally Harmonised System for the Classification and Labelling of Chemicals (GHS)), or not requiring classification for eye irritation or serious eye damage according to the GHS. The test item was applied in a single dose (30 mg/eye) onto the cornea of isolated chicken eyes and rinsed after 10 seconds with saline. Tested corneas were evaluated pre-treatment and at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention, and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points.

The Imidazole (positive control) was ground before use in the study. The test item and positive control were applied in an amount of 30 mg/eye by powdering the entire surface of the cornea attempting to cover the cornea surface uniformly with the test substance or positive control. Three test item treated eyes and three positive control eyes were used in this study.

One negative control eye was treated with 30 μL saline solution.

After an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with approximately 20 mL saline solution at ambient temperature and this procedure was repeated for each eye.

In this ICET, the test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes. With the overall ICE score of 2xI and 1xII, the substance is classified as "No Category". Positive and negative controls showed the expected results. The experiment was considered to be valid.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Justification for classification or non-classification

In an experimental study according to OECD test guideline 439 under GLP conditions, the test substance did not reduce cell viability. Therefore, it is considered to be not skin irritating and does not require to be classified (UN GHS 'No Category').

In an experimental study according to OECD test guideline 438 under GLP conditions, the test substance scored into ICE Class I for corneal opacity and swelling an into ICE Class II for fluorescein retention. With the overall ICE score of 2xI and 1xII, the substance is classified as "No Category" for eye irritation according to the GHS classification system.