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Diss Factsheets

Toxicological information

Eye irritation

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Administrative data

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-11-27 - 2013-04-24
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
L-Cysteine Hydrochloride Monohydrate
Cas Number:
175.63
Molecular formula:
C3H7NO2S·HCl·H2O
IUPAC Name:
L-Cysteine Hydrochloride Monohydrate
Test material form:
solid: granular

Test animals / tissue source

Species:
other: Fresh bovine eyes from Bos primigenius
Details on test animals or tissues and environmental conditions:
Fresh bovine eyes were obtained from the slaughterhouse Müller Fleisch GmbH, Enzstrasse 2.
4, D-75217 Birkenfeld, Germany. The cattle were between 12 and 60 months old. The eyes were
transported to the test facility in Hank's balanced salt solution. Then the corneas were dissected and incubated in medium at 32 +-1 °C in an incubation chamber for one hour.

Test system

Vehicle:
other: Incubation Medium MEM
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
20% in 0.9% NaCl. A stock solution of the test item was prepared freshly on the day of the assay. The test item was dissolved in 0.9% NaCl. It was checked whether the solution was clear and the pH was mesured. pH: 0.78.
Duration of treatment / exposure:
Open chamber method, exposition time on the corneas was 4 h at 32 °C
Duration of post- treatment incubation (in vitro):
After an initial incubation of one hour, the medium was changed and the baseline opacity for each cornea was recorded.
Exposition time on the corneas was 4 h at 32 °C. After thorough rinsing with cMEM and with phenol red and a final rinsing with cMEM without phenol red, the final opacity value of each cornea was recorded at 570 nm. The cMEM in the front chamber was exchanged with a sodium fluorescin solution. The chambers were then closed and incubated for 90 +-5 min at 32+-1 °C. After incubation, the content of the posterior chamber was thoroughly mixed. Then the permeability of the cornea was measured as optical density of the liquid at 490 nm.
Number of animals or in vitro replicates:
3
Details on study design:
REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: after 4 h of incubation
SCORING SYSTEM: opacity difference
TOOL USED TO ASSESS SCORE: spectral photometer Specord 205, Analytik Jena

Results and discussion

In vitro

Results
Irritation parameter:
other: opacity difference
Value:
9.815
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: mean opacity difference
Other effects / acceptance of results:
Substances with an opacity difference < 55.1 may be considered as non-corrosive or not severely irritant.
The positive control showed very severe eye irritation.

Applicant's summary and conclusion

Conclusions:
According to OECD 437 L-Cysteine Hydrochloride Monohydrate is classified as "non-corrosive" and/
or " no severe irritant".
Executive summary:

An in vitro study was performed to assess the corneal irritation and damage potential of L-Cysteine Hydrochloride Monohydrate. Bovine corneas were incubated for 4 hours with a 20% solution of the test item in 0.9% NaCl solution. Afterwards the change of opacity was measured and compared to negative and positive control groups. The changes in opacity of the control groups, 0.402 and 80.746, met the validity criteria.
L-Cysteine Hydrochloride Monohydrate caused a change in opacity of 9.815.
According to OECD 437 L-Cysteine Hydrochloride Monohydrat is classified as "non corrosive" and/or "no severe irritant".