Isobutyric acid, monoester with 2,2,4-trimethylpentane-1,3-diol

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

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:

Isobutyric acid, monoester with 2,2,4-trimethylpentane-1,3-diol

EC Number:

246-771-9

EC Name:

Isobutyric acid, monoester with 2,2,4-trimethylpentane-1,3-diol

Cas Number:

25265-77-4

Molecular formula:

C12H24O3

IUPAC Name:

3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoate

Details on test material:

The test substance, identified as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, Lot #: E175/1053, was received on September 6, 2011 and was further identified with EPSL Reference Number 110906-1D. The test substance was stored at room temperature in a dry area protected from direct sunlight. The sample was instilled as received. Documentation of the methods of synthesis, fabrication, or derivation of the test substance is retained by Perstop Oxo Belgium AB, Durmakker 33, B-9940 Evergem, Belgium.

The following information related to the characterization of the test substance was provided by the Sponsor:
Composition: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate- 99%
Physical description: Colorless liquid
pH: 2.54 at 20°C
Solubility: Water solubility: 1.5 giL at 20°C (OECD 105)
Stability: Test substance was expected to be stable for the duration of testing.
Expiration Date: August 31, 2012

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Husbandry

Housing:
The animals were singly housed in suspended stainless steel caging with mesh floors which confonn to the size recommendations in the most recent Guide for the Care and Use of Laboratory Animals (Natl. Res. Council, 2011). Litter paper was placed beneath the cage and was changed at least three times per week.

Animal Room Temperature and Relative Humidity Ranges:
19-23°C and 53-84%, respectively. Humidity was above the targeted upper limit for 3 days during the study. A portable dehumidifier was used to lower the humidity levels during this time.

Animal Room Air Changes/Hour:
Airflow measurements are evaluated regularly and the records are kept on file at Product Safety Labs.

Photoperiod: 12-hour light/dark cycle

Acclimation Period: 26 days

Food:
Harlan Teklad Global High Fiber Rabbit Diet® #2031. A designated amount of the diet was available to each rabbit (approximately 150 grams/day).
Water: Filtered tap water was supplied ad libitum by an automatic water dispensing system.

Contaminants:
There were no known contaminants reasonably expected to be found in the food or water at levels which would have interfered with the results of this study. Analyses of the food and water are conducted regularly and the records are kept on file at Product Safety Labs.

Identification

Cage: Each cage was identified with a cage card indicating at least the study number and identification and sex of the animal.

Animal: A number was allocated to each rabbit on receipt and a stainless steel ear tag bearing this number was attached to the animal. This number, together with a sequential animal number assigned to study 33026, constituted unique identification.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

Prior to instillation, 2-3 drops of ocular anesthetic (Tetracaine Hydrochloride Ophthalmic Solution, 0.5%) were placed into both the treated and control eye of each animal. One-tenth of a milliliter of the test substance was then instilled into the conjunctival sac of the right eye of each rabbit by pulling the lower lid away from the eyeball. The upper and lower lids were then gently held together for about one second before releasing to minimize loss of the test substance. The other eye of each rabbit remained untreated with the test substance and served as a control. The rabbits were then returned to their designated cages.

Duration of treatment / exposure:

Test substance was applied once and allowed to remain in the treated eye for the duration of the study.

Observation period (in vivo):

Ocular irritation was evaluated at 1, 24, 48, and 72 hours and at 4 days post-instillation.

Number of animals or in vitro replicates:

3

Details on study design:

Preparation and Selection of Animals

Prior to test initiation, both eyes of a group of animals were examined using a white light source and a fluorescein dye procedure. One drop of 2% ophthalmic fluorescein sodium was instilled into both eyes of each rabbit. The eyes were rinsed with physiological saline (0.9% NaCl) approximately 30 seconds after instillation of the fluorescein and then evaluated for corneal damage using an ultraviolet light source. Prior to instillation, the eyes were re-examined and scored for abnormalities according to the "Scale for Scoring Ocular Lesions". Three healthy animals without pre-existing ocular irritation were selected for test.

Ocular Scoring

Ocular irritation was evaluated using a high-intensity white light (Mag Lite) at 1, 24, 48, and 72 hours and at 4 days post-instillation. The fluorescein dye evaluation procedure described in Section 5.A. was used in the treated eye at 24 hours and as needed at subsequent scoring intervals to evaluate the extent of corneal damage or to verify reversal of effects. Individual scores were recorded for each animal. In addition to observations of the cornea, iris and conjunctivae, any other observed lesions were noted. The average score for all rabbits at each scoring period was calculated to aid in data interpretation .

Classification of Eye Scores

The time interval with the highest mean score (Maximum Mean Total Score - MMTS) for all rabbits was used to classify the test substance by the system of Kay and Calandra. The average individually-determined irritation scores for cornea, iris and conjunctiva (redness and chemosis)
across 24, 48 and 72 hours were calculated for EC3 classification.

Cage-Side Observations

The animals were observed for signs of gross toxicity and behavioral changes at least once daily during the test period.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

10

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 2

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 3

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

2

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 4

Irritation parameter:

iris score

Basis:

animal #2

Time point:

other: 1 hour, and 1,2,3,4 days after instillation.

Score:

0

Max. score:

0

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 5

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

other: 1 hour, and 1,2,3,4 days after instillation.

Score:

0

Max. score:

1

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 6

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

other: 1 hour, and 1,2,3,4 days after instillation.

Score:

1

Max. score:

1

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 7

Irritation parameter:

iris score

Basis:

animal #3

Time point:

other: 1 hour, and 1,2,3,4 days after instillation.

Score:

2

Max. score:

0

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 8

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

other: 1 hour, and 1,2,3,4 days after instillation.

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 4 days

Remarks on result:

other: See table for scores at individual time points

Results 9

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1.3

Max. score:

10

Reversibility:

fully reversible

Remarks on result:

not determinable

Results 10

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.33

Max. score:

10

Reversibility:

fully reversible

Remarks on result:

not determinable

Results 11

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1

Max. score:

10

Reversibility:

fully reversible

Remarks on result:

not determinable

Irritant / corrosive response data:

The incidence of positive effects is presented in Table 1. All animals appeared active and healthy during the study. Apart from the eye irritation noted below, there were no other signs of gross toxicity, adverse pharmacologic effects, or abnormal behavior. There was no iritis observed in any treated eye during this study. One hour after test substance instillation, all three treated eyes exhibited 'positive' conjunctivitis. By 24 hours, corneal opacity also developed in two animals. The overall incidence and severity of irritation decreased thereafter. All animals were free of ocular irritation by Day 4 (study termination). The Maximum Mean Total Score of2,2,4-trimethyl-1,3-pentanediol monoisobutyrate is 16.0. The individually determined mean irritation (EC Mean Score) scores for each animal for corneal opacity, iris lesion and conjunctival (redness and chemosis) for the 24, 48 and 72-hour intervals are presented in Table 2. The mean scores for severity are presented in table 3.

Any other information on results incl. tables

Cornea

Opacity-degree of density (area most dense taken for reading)

No Opacity ........................................................................................................................................................................ 0

Scattered or diffuse area, details of iris clearly visible ........................................................................................................... 1

Easily discernible translucent areas, details of iris slightly obscured ....................................................................................... 2 Opalescent areas, no details of iris visible, size of pupil barely discernible ............................................................................. 3 Opaque, iris invisible .......................................................................................................................................................... 4

Area of cornea involved

One quarter (or less) but not zero ........................................................................................................................................ 1 Greater than one quarter, but less than half ........................................................................................................................... 2 Greater than half, but less than three quarters ........................................................................................................................ 3 Greater than three quarters, up to whole area ....................................................................................................................... 4

A X B X 5 Total Maximum = 80

Iris

Values

Normal ............................................................................................................................................................................... O Folds above normal, congestion, swelling, circumcorneal injection (any or all of these or combination of any thereof)

iris still reacting to light (sluggish reaction is positive) .............................................................................................................. 1

No reaction to light, hemorrhage, gross destruction (any or all ofthese) .................................................................................. 2

A X 5 Total Maximum= 10

Conjunctivae

Redness (refers to palpebral and bulbar conjunctivae excluding cornea and iris)

Vessels normal ..................................................................................................................................................................... 0 Vessels definitely injected above normal ................................................................................................................................ 1 More diffuse, deeper crimson red, individual vessels not easily discernible .............................................................................. 2

Diffuse beefy red .................................................................................................................................................................. 3

Chemosis

No swelling ......................................................................................................................................................................... 0

Any swelling above normal (includes nictitating membrane) ................................................................................................... 1

Obvious swelling with partial eversion of lids ........................................................................................................................ 2 Swelling with lids about half-closed ...................................................................................................................................... 3 Swelling with lids about half-closed to completely closed ...................................................................................................... 4

Discharge

No discharge ....................................................................................................................................................................... 0

Any amount different from normal (does not include small amounts observed in inner canthus of normal animals) .................... 1

Discharge with moistening of the lids and hairs just adjacent to lids ........................................................................................ 2 Discharge with moistening of the lids and hairs, and considerable area around the eye ............................................................ 3

Score (A+ B + C) X 2

Total Maximum= 20 Total Maximum Score: 110 represents the sum of all scores obtained for the cornea, iris and conjunctivae.

Classification of eye irritation scores

MMTS	Irritation classification	Requirement for Maintenance of Classification
0.0 - 0.5	non	Up to 0.5 at 1 hour with zeros at 24 hours; otherwise, increase one level
0.6-2.5	practically non	with zeros at 24 hours; otherwise, increase one level
2.6- 15.0	minimally	with zeros at 48 hours; otherwise, increase one level
15.1-25.0	mildly	with zeros at 96 hours; otherwise, increase one level
25.1- 50.0	moderately	with 7 day mean ~20 and individual total scores ~1 0 in at least 60% of the rabbits with no total score >30; otherwise, increase one level
50.1 - 80.0	severely	with 7 day mean ~ 40 and individual total scores ~3 0 in at least 60% of the rabbits with no total score> 60; otherwise, increase one level
80.1 - 100.0	extremely	with 7 day mean ~80 and individual total scores ~60 in at least 60% of the rabbits with no total score > 1 00; otherwise, increase one level
100.1- 110	maximally	with 7 day mean > 80 and individual total scores > 60 in at least 60% of the rabbits; otherwise, decrease one level

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

Under the conditions of this study, 2,2,4-trimethyl-1 ,3-pentanediol monoisobutyrate was considered to be mildly irritating to the eye. Based on the results of this study, 2.2.4-trimethyl-1 ,3-pentanediol monoisobutyrate does not meet the criteria for GHS Toxicity and EC classification, and therefore, no risk phrase for ocular irritation is required .

Executive summary:

A primary eye irritation test was conducted with rabbits to determine the potential for 2,2,4- trimethyl-1,3-pentanediol monoisobutyrate to produce irritation from a single instillation via the ocular route. One-tenth of a milliliter of the test substance was instilled into the right eye of three healthy rabbits. The left eye remained untreated and served as a control. Ocular irritation was evaluated by the method of Draize et al.. There was no iritis observed in any treated eye during this study. One hour after test substance instillation, all three treated eyes exhibited 'positive' conjunctivitis. By 24 hours, corneal opacity also developed in two animals. The overall incidence and severity of irritation decreased thereafter. All animals were free of ocular irritation by Day 4 (study termination). Under the conditions of this study, 2,2,4-trimethyl-1 ,3-pentanediol monoisobutyrate was considered to be mildly irritating to the eye. Based on the results of this study, 2.2.4-trimethyl-1 ,3-pentanediol monoisobutyrate does not meet the criteria for GHS Toxicity and EC classification, and therefore, no risk phrase for ocular irritation is required .