L-cysteine

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD Guidline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

L-cysteine

EC Number:

200-158-2

EC Name:

L-cysteine

Cas Number:

52-90-4

Molecular formula:

C3H7NO2S

IUPAC Name:

L-cysteine

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Name: L-Cysteine
Chemical Name: L-( +)-Cysteine
CAS No.: 52-90-4
Batch No.: 12030506
Physical State: solid
Colour: white
Molecular Weight: 121.1
pH: 4.5-6
Storage Conditions: 2-8°C, protected from light

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Species/strain: healthy New Zealand White Rabbits, Crl: KBL (NZW)
Source: Charles River Deutschland, 97633 Sulzfeld, Germany
Sex: female
Body weight at the beginning of the study: > 2 kg
Age at the beginning of the study: approximately 19 weeks old
Number of animals: 3

Semi barrier in an air-conditioned room
Temperature: 18 ± 3 °C
Relative humidity: 55 ± 10%
Artificial light, sequence being 12 hours light, 12 hours dark
Air change: at least 10 x I hour
Free access to autoclaved hay and to Altromin 2123 maintenance diet for rabbits (lot no. 0650), rich in crude fibre. Free access to tap water (drinking water, municipal residue control, microbi-ological controls at regular intervals)
Housed in ABS - plastic rabbit cages, floor 4200 cm2
Adequate acclimatisation period (at least 5 days) under laboratory conditions

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: other eye served as a control

Amount / concentration applied:

The test item (0.1 g) was applied at a single dose in the conjunctival sac of one eye of each test animal after pulling the lower lid away from the eyeball. The lids were then gently held together for about 1 second in order to prevent loss of the material. The untreated contralateral eye served as control.

Duration of treatment / exposure:

The treated eye was not rinsed 24 hours after the application.

Observation period (in vivo):

The animals were observed for 72 hours after dosing.

Number of animals or in vitro replicates:

3

Details on study design:

Approximately 24 hours before the test and immediately prior to the application both eyes of each animal were examined. A health inspection was performed to ensure the good state ofhealth ofthe animals. Approximately 24 hours before the application the eyes were also examined with the aid
of a fluorescein solution (Fluoreszein SE Thilo®). The eyes were rinsed with physiological saline 0.9% NaCl (AlleMan Pharma, lot no. 111214, expiry date: 11/2014) after the examination. None of the animals showed eye irritation, ocular defects, or pre-existing corneal injury.
One hour before the application of the test item, 0.01 mg/kg of buprenorphine (Reckitt Benckiser, lot no.: 5230, expiry date: 02/2016) was administered subcutaneously in order to achieve a therapeutic level of systemic analgesia. Approximately 5 minutes prior to the application ofthe test item, 2-3 drops of an ocular anaesthetic (proparacaine hydrochloride ophtalmic 0.5% solution, Ursapharma, were administered in both the treated and the
control eye of each animal. The test item was applied at a single dose in the conjunctival sac of one eye of each test animal after pulling the lower lid away from the eyeball. The lids were then gently held together for about 1 second in order to prevent loss of the material. The untreated
contralateral eye served as control. The eyes were examined for signs of irritation throughout the observation period. At the end of the observation period the treated eyes were examined with the aid of a fluorescein solution (Fluoreszein SE Thilo®). The eyes were rinsed with physiological saline 0.9% NaCl after the examination.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

iris score

Basis:

mean

Time point:

other: all

Score:

0

Max. score:

2

Results 2

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

other: 24 h

Score:

2

Max. score:

3

Reversibility:

not fully reversible within: 48 h

Results 3

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: any

Score:

0

Max. score:

4

Results 4

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

other: an

Score:

0

Max. score:

4

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The substance is not irritating to eyes under the conditions of this study.

Executive summary:

An eye irritation study according to OECD Guideline 405 was performed with L-Cysteine. 0.1 g of the pure test substance was administered into the conjunctival sac of the eye of three New Zealand White rabbits. The eyes were not rinsed after the application.

After the application into the eyes of three female NZW rabbits the test item produced slight irritant but no corrosive ocular effects.

Upon fluorescein examinations at the end of the observation period of 72 hours no corneal lesions were found in any animal.

Conjunctival redness was observed in all animals, discharge in one animal. There were no significant body weight changes during the observation period. Under the conditions of the present study, a single ocular application of the test item LCysteine

to rabbits at a dose of 0.1 g produced slight irritant effects, which were fully reversible within 48 hours. Neither mortalities nor significant clinical signs of toxicity were observed.

In conformity with the EC criteria for classification and labelling requirements the test item L-Cysteine has no obligatory labelling requirement for eye irritation.