2-hydroxy-4-(methylthio)butyronitrile

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From: 3 February 1999 To: 14 February 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline 405

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxy-4-(methylthio)butyronitrile

EC Number:

241-756-3

EC Name:

2-hydroxy-4-(methylthio)butyronitrile

Cas Number:

17773-41-0

Molecular formula:

C5H9NOS

IUPAC Name:

2-hydroxy-4-(methylsulfanyl)butanenitrile

Details on test material:

- Name of test material (as cited in study report): 2-hydroxy-4-méthylthiobutyronitrile
- Physical state: pale yellow liquid
- Analytical purity: 75.77% (TOS) / 74.5 % (HPLC)
- Purity test date: no data
- Lot/batch No.: MO69
- Expiration date of the lot/batch: no data
- Storage condition of test material: at room temperature

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Elevage Cunicole de Val de Selle, 80160 Prouzel, France.
- Age at study initiation: no data
- Weight at study initiation: the animals had a mean body weight of 2.4+/- 0.3 kg.
- Housing: individually in polystyrene cages
- Diet : ad libitum, 112 C pelleted diet (UAR, 91360 Villemoisson-sur-Orge, France)
- Water : ad libitum, water filtered by a FG Millipore membrane (0.22 micron)
- Acclimation period: at least 5 days before the beginning of the study


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3
- Humidity (%): 30 to 70
- Air changes (per hr): 12
- Photoperiod : 12 hrs dark / 12 hrs light


IN-LIFE DATES: From: 3 February 1999 To: 14 February 1999

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated eye

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 ml

Duration of treatment / exposure:

not rinsed

Observation period (in vivo):

a maximum of 21 days
Examination time points: 1 hour, 24, 48 and 72 hours

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
The eyes were not rinsed after administration of the test substance.

SCORING SYSTEM:

Cornea
Opacity: degree of density (readings should be taken from most dense area)*
No ulceration or opacity.............................................................................................................................. 0
Scattered or diffuse areas of opacity (other than slight dulling of normal lustre);
details of iris clearly visible ...................................................................................................................... 1
Easily discernible translucent area; details of iris slightly obscured ............................................................2
Nacrous area; no details of iris visible; size of pupil barely discernible ......................................................3
Opaque cornea; iris not discernible through the opacity ..............................................................................4
Maximum possible: 4

Area of opacity
One quarter (or less) but not zero...................................................1
greater than one quarter but less than a half.................................2
greater than one half but less than three quarters........................3
greater than three quarters up to whole area.................................4

Iris
Normal ...................................................................................................................................................................................................0
Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia;
or injection, any of these or combination of any therof, iris still reacting to light (a sluggish reaction is positive)............1
no reaction to light, Hemorrhage, gross destruction, (any or all of these .................................................................................2
Maximum possible: 2

Conjunctivae
Discharge
Absence of discharge.......................................................................................................................................0
slight discharge (does not include small amounts normally found in inner canthus)...........................1
Discharge with moistening of lids and hairs adjacent to lids......................................................................2
Discharge with moistening of lids and hairs on wide area around the eye...............................................3
Maximum possible: 3

Conjunctivae
Redness (refers to palpebral and bulbar conjunctivae; excluding cornea and iris)
Blood vessel normal .........................................................................................................................................0
A number of blood vessels definitely hyperaemic (injected) .....................................................................1
Diffuse, crimson colour; individual vessels not easily discernible ...........................................................2
Diffuse beefy red................................................................................................................................................3
Maximum possible: 3

Chemosis
Swelling (refers to lids and/or nictating membranes)
No swelling.......................................................................................................................................................0
Any swelling above normal (includes nictitating membranes)................................................................1
Obvious swelling, with partial eversion of lids...........................................................................................2
Swelling, with lids about half closed ............................................................................................................3
Swelling, with lids more than half closed .....................................................................................................4
Maximum possible: 4

TOOL USED TO ASSESS SCORE: fluorescein (One or two drops of 0.5 % sodium fluorescein solution can be instilled into the eye to evaluate the corneal opacification and the affected area)

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

other: 24, 48 and 72 hour

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 8 days

Results 2

Irritation parameter:

iris score

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

0.77

Max. score:

2

Reversibility:

fully reversible within: 6 days

Results 3

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 11 days

Results 4

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 11 days

Irritant / corrosive response data:

Conjunctival reactions were observed in all animals from day 1: a chemosis (grade 1 or 2), a redness of the conjunctiva (grade 1 or 2) and clear to whitish purulent discharge were noted. These reactions persisted up to day 11 at the latest.
An iritis (grade 1) was noted in one animal between day 1 and day 6, in another one between day 3 and day 5 and in the third one in days 3 and 4. A corneal opacity (grade 1 or 2) was recorded in all animals on day 2; it persisted up to day 6 or 8. Neovascularisation and alopecia around the eye were noted in all animals, from day 3 or day 5 up to day 5, 6 or 7.
Mean scores calculated for each animal over 24, 48 and 72 hours were 2.0, 2.0 and 2.0 for chemosis, 2.0, 2.0 and 2.0 for redness of the conjunctiva 1.0, 0.7 and 0.7 for iris lesions and 2.0, 2.0 and 2.0 for corneal opacity.

Other effects:

None

Any other information on results incl. tables

Table: Irritant/corrosive response data for each animal at each observation time up to removal of each animal from the test

Score at time point/ Reversibility	Cornea Max. score: 4	Iris Max. score: 2	Conjunctivae Max. score: 3	Chemosis Max. score: 4
60 min	0/0/0	1/0/0	1/1/1	1/1/2
24 h	2/2/2	1/0/0	2/2/2	2/2/2
48 h	2/2/2	1/1/1	2/2/2	2/2/2
72 h	2/2/2	1/1/1	2/2/2	2/2/2
Mean scores over 24, 48 and 72 hours for each animal	2/2/2	1/0.66/0.66	2/2/2	2/2/2
Average 24h, 48h, 72h calculated over all the animal tested	2	0.77	2	2
Reversibility*)	c.	c.	c.	c.

*) Reversibility: c.=completely reversible; n.c.= not completely reversible; n= not reversible

Applicant's summary and conclusion

Interpretation of results:

other: category 2

Remarks:

Criteria used for interpretation of results: other: EU

Conclusions:

Under these experimental conditions, the test substance 2-hydroxy-4-méthylthiobutyronitrile is irritant when administered by ocular route to rabbits. According to classification criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations), 2-hydroxy-4-méthylthiobutyronitrile is considered as irritating to eyes and according to CLP regulation the test substance is classified as irritating to eyes (category 2).

Executive summary:

The potential of 2-hydroxy-4-méthylthiobutyronitrile to induce ocular irritation was evaluated in rabbits according to OECD (No.405, 24th February 1987) and EC (92/69/EEC, B.5, 31st July 1992) guidelines. The test substance was first administered to a single male New Zealand rabbit. Since the item was not severely irritant on this fisrt animal, it was then evaluated simultaneously in two other animals.

Asingle dose of 0.1 ml of the undiluted test substance was instilled into the leftconjunctival sac. The right eye was not treated and served as control. The eyes were not rinsed after administration of the test substance. Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration and then daily until reversibility of the ocular reactions. The mean values of the scores for chemosis, redness of the conjunctiva, iris lesions and corneal opacity were calculated for each animal.

Mean scores calculated for each animal over 24, 48 and 72 hours were 2, 2 and 2 for chemosis, 2, 2 and 2 for redness of the conjunctiva and 2, 2 and 2 for corneal opacity. Under these experimental conditions, the test substance was irritant when administered by ocular route to rabbits. According to classification criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations), 2-hydroxy-4-méthylthiobutyronitrile is considered as irritating to eyes and according to CLP regulation the test substance is classified as irritating to eyes (category 2).