Glycollic acid

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted and reported prior to introduction of test guidelines. Non-GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

study conducted prior to guidelines

Deviations:

yes

Remarks:

; in contrast to current guidelines much of the standard method detail is omitted. Use of the Draize assessment for ocular scoring is omitted. Insufficient detail to determine average scores or reactions at 24 to 72 hours post-instillation

GLP compliance:

no

Remarks:

study conducted prior to GLP introduction

Test material

Test material information

Constituent 1

Reference substance name:

Glycollic acid

EC Number:

201-180-5

EC Name:

Glycollic acid

Cas Number:

79-14-1

Molecular formula:

C2H4O3

IUPAC Name:

2-hydroxyacetic acid

Details on test material:

Glycolic acid 70% solution

Test animals / tissue source

Species:

rabbit

Strain:

other: Albino

Details on test animals or tissues and environmental conditions:

No further information.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.1 mL of test material was dosed into the right conjunctival sac of each rabbit.
- Amount(s) applied (volume or weight with unit):0.10 mL .
- Concentration (if solution): Undiluted.

Duration of treatment / exposure:

After 20 seconds, the treated eye of one rabbit was washed with tap water for one minute. The treated eye of the other rabbit was not washed.

Observation period (in vivo):

Assessments at 1 and 4 hours; and 1, 2, 3, 7, and 14 days.
14 days post exposure observation

Number of animals or in vitro replicates:

2

Details on study design:

Examination: 1 and 4 hours, 1, 2, 3, 7and 14 days after instillation.
Observations of cornea, iris and conjunctiva were made with a hand-slit lamp; Fluor-i-strip® stain and a biomicroscope were used in examinations after the day of treatment.
REMOVAL OF TEST SUBSTANCE
- Washing (if done): Yes, one animal's treated eye with tap water for 1 minute. Other animal's treated eye not washed.
- Time after start of exposure: 20 seconds.
SCORING SYSTEM: No data or observations.
TOOL USED TO ASSESS SCORE: Hand-slit lamp at 1 and 4 hours; and 1, 2, 3, 7, and 14 days. Fluor-i-strip stain and a biomicroscope used after day of treatment.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 3

Max. score:

3

Reversibility:

not reversible

Remarks:

7 days

Remarks on result:

other: Moderate to total opacity

Results 2

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 3

Max. score:

3

Reversibility:

not reversible

Remarks:

14 d

Remarks on result:

other: Eye shrunken and cornea looked soft

Results 3

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 3

Max. score:

3

Reversibility:

not reversible

Remarks:

7 d

Remarks on result:

probability of severe irritation

Remarks:

corrosive in 7 days in unwashed eye

Results 4

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 3

Max. score:

3

Reversibility:

not reversible

Remarks:

14 d

Remarks on result:

probability of severe irritation

Remarks:

corrosive in 3-14 days in washed eye

Results 5

Irritation parameter:

iris score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 1.5

Max. score:

1.5

Reversibility:

not reversible

Remarks:

24 h

Remarks on result:

other: Moderate congestion of vessels with slight pupil constriction

Results 6

Irritation parameter:

iris score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 1.5

Max. score:

1.5

Reversibility:

not reversible

Remarks:

7 d

Remarks on result:

other: Severe gross destruction of iris

Results 7

Irritation parameter:

iris score

Basis:

mean

Remarks:

animals #1,#2

Time point:

24/48/72 h

Score:

>= 1.5

Max. score:

1.5

Reversibility:

not reversible

Remarks:

14 d

Remarks on result:

other: Lens appeared to be displaced with risk of rupturing the soft cornea. No reaction to light.

Results 8

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #1,#2

Time point:

24/48/72 h

Score:

>= 0

Max. score:

0

Reversibility:

not specified

Remarks on result:

not measured/tested

Irritant / corrosive response data:

Instillation of glycolic acid to the eyes of two rabbits resulted severe, irreversible ocular damage.
The results indicate that glycolic acid is corrosive to rabbit eyes.

Eye not washed:
Cornea - Moderate to slight opacity at 1 hour. Moderate to total opacity (opalescent) from 4 hours to 7 days. Corneal swelling moderate to severe at 1-3 days. Thin spots at 7 days. Eye shrunken and cornea looked soft at 14 days.
Iris - Moderate congestion of vessels with slight pupil constriction at 1 hour to 1 day. Severe gross destruction of iris at 2-7 days. Lens appeared to be displaced with risk of rupturing the soft cornea at 14 days. No reaction to light.
Conjunctiva - Blanched with necrotic areas at 1 hour to 2 days. Hemorrhages at 3 days. Corrosive at 7 days. Mild swelling at 1 hour, becoming moderate to severe at 4 hours to 1 day. Severe at 2 to 7 days. Eyelids becoming hardened at 7 days. Copious, Hemastix positive discharge at 1 hour to 7 days, becoming purulent at 2 to 7 days.

Washed:
Cornea - Slight to total opacity at 1 hour to 14 days. Area (~1/4 of cornea) very dense and red (could not see individual blood vessels) at 7 days. Center of cornea almost clear and bulging with vascularization and adhesions of sclera to cornea at all edges at 14 days.
Iris - Moderate congestion of vessels with slight pupil constriction at 1-4 hours. Moderate congestion with remarkable flare 1-3 days. Severe possible destruction of iris at 7 days. No reaction to light at 14 days.
Conjunctiva - Blanched with necrotic areas at 1 hour to 2 days. Corrosive at 3 to 14 days. Moderate to mild swelling at 1 hour to 1 day. Severe swelling at 2 to 14 days. Eyelid becoming hardened at 3 days. Copious, Hemastix positive discharge at 1 hour to 7 days, becoming purulent at 2 days.

Any other information on results incl. tables

Glycolic acid was corrosive to rabbit eyes. Ocular effects were severe and irreversible. By 14 days the test was terminated because one treated eye had become very small and had no reaction to light. The other treated eye did react to light, but the cornea looked like it could rupture.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Glycolic acid is classified as an eye irritant. Although study conducted and reported prior to introduction of test guidelines the information provided is sufficient to conclude the corrosive nature of the material and to justify the classification and labelling of glycolic acid. Glycolic acid is corrosive to rabbit eyes at the concentration and dose (0.10 mL) used in this test. Ocular effects were severe and irreversible. By 14 days the test was terminated because one treated eye had become very small and had no reaction to light. The other treated eye did react to light, but the cornea looked like it could rupture. This acid behaves in much the same way as strong mineral acids in contact with ocular tissue.

Executive summary:

Two albino rabbits were dosed by instillation of 0.1 mL of glycolic acid into the right conjunctival sac of one eye. The test substance was left ‘in situ’ in the first rabbit; the eye of the second rabbit was rinsed for one minute with tap water 20 seconds after instillation. Ocular irritation was evaluated after 1 and 4 hours, 1, 2, 3, 7 and 14 days post-instillation. Effects were seen in the cornea, iris and conjuctiva one hour after dosing in both rabbits. By 14 days, observation was terminated because one treated (unwashed) eye, which had become very small, had no reaction to light. The other eye (washed) reacted to light although the cornea appeared as if it would rupture. Glycolic acid is corrosive to rabbit eyes.

 

Study conducted and reported prior to introduction of test guidelines. In principle the investigations meet the objectives of current guidelines but much of the standard method detail is omitted. Use of the Draize assessment for ocular scoring is omitted. There is insufficient detail to determine average scores or reactions at 24 to 72 hours post-instillation.

 

However, the information provided is sufficient to conclude the corrosive nature of the material and to justify the classification and labelling of glycolic acid. The results indicate that glycolic acid is corrosive to rabbit eyes.