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Diss Factsheets

Administrative data

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1995-03-02 to 1995-03-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report date:
1995

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 438 (Isolated Chicken Eye Test Method for Identifying Ocular Corrosives and Severe Irritants)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Butyl (S)-2-hydroxypropionate
EC Number:
252-036-3
EC Name:
Butyl (S)-2-hydroxypropionate
Cas Number:
34451-19-9
Molecular formula:
C7H14O3
IUPAC Name:
butyl 2-hydroxypropanoate
Specific details on test material used for the study:
- Name: n-butyl lactate
- Chemical name: butyl-(S)-2-hydroxypropionate
- CAS: 34451-19-9 (S-isomer), 138-22-7 (general)
- Labeling: Butyl lactate
- Package: White, plastic bottle
- Purity: 99.06 %
- General appearance: Clear, colourless liquid
- Storage conditions: Ambient

Test animals / tissue source

Species:
other: chicken eyes
Details on test animals or tissues and environmental conditions:
Approximately 7 weeks old, male or female chickens (ROSS, spring chickens), body weight range approximately 2.5–3.0 kg, were used as eye-donors. Heads of these animals were obtained from poultry slaughterhouse v.d. Bor, Amersfoortseweg 118, Nijkerkerveen, the Netherlands. Within 2 hours after kill, eyes were carefully dissected and placed in a supervision apparatus. The enucleated eyes were placed in a stainless steel clamp with the cornea positioned vertically and transferred to a chamber of the superfusion apparatus. The corneal integrity was assessed in all eyes. Eyes with a corneal thickness deviating more than 10 % of the average corneal thickness of the eyes, or eyes that were unacceptably stained with fluorescein (score higher than 0.5), indicating the cornea to be permeable, or eyes that showed any other signs of damage, were rejected as test eyes and replaced, if necessary. Four eyes were selected for testing.

Test system

Vehicle:
unchanged (no vehicle)
Controls:
other: 1 control eye treated with isotonic saline
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.03 mL
Duration of treatment / exposure:
10 sec
Observation period (in vivo):
240 min
Number of animals or in vitro replicates:
not applicable
Details on study design:
REMOVAL OF TEST SUBSTANCE
- Washing (if done): each was washed out with 20 mL of isotonic saline; after rinsing the eyes were examined at 0, 30, 75, 120, 180 and 240 min.

ENDPOINTS MEASURED
Corneal opacity, swelling, fluorescein retention and morphological effects

SCORING SYSTEM
- Corneal swelling: [(CT at t - CT at t=0)/ CT at t=0] × 100%, where CT: corneal thickness
- Corneal opacity: Opacity degree of density (area most dense taken for scoring)
0 = no opacity; 0.5 = very faint opacity; 1 = scattered or diffuse areas, details of iris clearly visible; 2 = easily discernible translucent area, details of iris slightly obscured; 3 = severe corneal opacity, no specific details of iris visible, size of pupil barely discernible; 4 = complete corneal opacity, iris invisible

TOOL USED TO ASSESS SCORE: Slit lamp microscope

Results and discussion

In vitro

Resultsopen allclose all
Irritation parameter:
percent corneal swelling
Remarks:
after 240 min
Run / experiment:
1
Value:
39
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
percent corneal swelling
Remarks:
after 240 min
Run / experiment:
2
Value:
44
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
percent corneal swelling
Remarks:
after 240 min
Run / experiment:
3
Value:
41
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
cornea opacity score
Remarks:
after 240 min
Run / experiment:
1
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
cornea opacity score
Remarks:
after 240 min
Run / experiment:
2
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
cornea opacity score
Remarks:
after 240 min
Run / experiment:
3
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
fluorescein retention score
Remarks:
after 30 min
Run / experiment:
1
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
fluorescein retention score
Remarks:
after 30 min
Run / experiment:
2
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation
Irritation parameter:
fluorescein retention score
Remarks:
after 30 min
Run / experiment:
3
Value:
3
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
not examined
Remarks on result:
positive indication of irritation

Applicant's summary and conclusion

Interpretation of results:
Category 1 (irreversible effects on the eye) based on GHS criteria
Conclusions:
n-Butyl-S-lactate is highly irritating and possibly corrosive to the eye of chicken when tested with a single application under the conditions of the present test. On the basis of these results, it is recommended not to perform the standard rabbit eye irritation test with n-butyl-S-lactate in rabbits, but to classify the test substance as an eye irritant Category 1.
Executive summary:

n-Butyl-S-lactate was examined for eye irritating/corrosive potential in an ex vivo bioassay, the enucleated eye test with chicken eyes (CEET). The chicken eyes were obtained from slaughter animals for human consumption. Four chicken eyes were used (one as a control, washed with physiological saline). Although the study was performed before the adoption of the OECD guideline 438 for this test, the design was very similar to the design proposed in the aforementioned guideline. The sample caused severe corneal swelling, severe corneal opacity and severe fluorescein retention of damaged corneal epithelium in the test eyes. On the basis of the results obtained with this investigation and according to the scheme for (EC) classification applied, it is concluded that n-butyl-S-lactate is severely irritating and possibly corrosive to eyes. On the basis of these results, it is recommended not to perform the standard rabbit eye irritation test with n-butyl-S-lactate in rabbits, but to classify the test substance as an eye irritant Category 1.