2,4,4-trimethylpentene

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other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,4,4-trimethylpentene

EC Number:

246-690-9

EC Name:

2,4,4-trimethylpentene

Cas Number:

25167-70-8

Molecular formula:

C8H16

IUPAC Name:

2,4,4-trimethylpent-1-ene

Details on test material:

- Name of test material (as cited in study report): 2,4,4-trimethylpentene (also known as diisobutylene and diisobutene)
- Physical state: clear, colourless liquid
- Analytical purity: 95.19%
- Lot/batch No.: Batch No. 2 (a 50:50 mixture of two original batches of 2,4,4-trimethylpentene - the details of which are as follows: Batch No. R11 supplied by Shell and Batch No. 155833 supplied by Erdolchemie).
- Expiration date of the lot/batch: 29 April 1997
- Storage condition of test material: Under nitrogen, protected from light, in a cool store.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

- Source: Froxfield SPF Rabbits, Broadway Farm, Froxfield, Hampshire, England
- Age at study initiation: Approximately 5 months
- Weight at study initiation: 2330-2510 g
- Housing: Individually housed in suspended stainless steel cages
- Diet: Standard pelleted rabbit diet (STANRAB (P) SQC - Special Diets Services Ltd., Witham, Essex, England) ad libitum
- Water: Tap water ad libitum
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature: 18-25°C
- Humidity: 40-68%
- Air changes: at least 10/hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 24 June 1996 To: 2 July 1996

Test system

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.1 mL

Duration of treatment / exposure:

Single instillation into the conjunctival sac

Observation period (in vivo):

Observed constantly for several minutes immediately after instillation. At least twice during first hour after instillation and at least twice daily thereafter.

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing: No

SCORING SYSTEM: As described in the regulatory guidelines and in addition: assessment of initial pain on a 0-5 scale, eye discharge on a 0-4 scale and area of cornea affected by lesions (if any) on a 0-4 scale

TOOL USED TO ASSESS SCORE: ophthalmoscope or pencil beam torch

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24 h

Score:

0

Max. score:

4

Results 2

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

48 h

Score:

0

Results 3

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

72 h

Score:

0

Results 4

Irritation parameter:

iris score

Basis:

mean

Time point:

24 h

Score:

0

Max. score:

2

Results 5

Irritation parameter:

iris score

Basis:

mean

Time point:

48 h

Score:

0

Results 6

Irritation parameter:

iris score

Basis:

mean

Time point:

72 h

Score:

0

Results 7

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24 h

Score:

1

Results 8

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

48 h

Score:

1

Results 9

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

72 h

Score:

0.86

Max. score:

3

Reversibility:

fully reversible within: 8 days in 2 rabbits

Remarks on result:

other: reversible in 72 h in 1 rabbit

Results 10

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24 h

Score:

0

Max. score:

4

Results 11

Irritation parameter:

chemosis score

Basis:

mean

Time point:

48 h

Score:

0

Results 12

Irritation parameter:

chemosis score

Basis:

mean

Time point:

72 h

Score:

0

Irritant / corrosive response data:

Instillation caused slight initial pain in one animal but there was no initial pain response in the other 2 animals.
Injection of the conjunctival blood vessels was present in each animal during the first 72 hours after instillation and iritis was present in one animal at the 1 hour assessment only. All signs of eye irritation had resolved by day 8.

Any other information on results incl. tables

Eye irritation scores according to the Draize scheme

Time		Cornea			Iris			Conjunctiva
								Redness			Chemosis
Animal number		703	716	717	703	716	717	703	716	717	703	716	717
after 1 hour		0	0	0	1	0	0	1	1	1	0	0	0
after 24 hours		0	0	0	0	0	0	1	1	1	0	0	0
after 48 hours		0	0	0	0	0	0	1	1	1	0	0	0
after 72 hours		0	0	0	0	0	0	1	1	0	0	0	0
mean scores 24-72h		0	0	0	0	0	0	1	1	0.6	0	0	0

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

2,4,4-trimethylpentene is not classified as "irritant to the eye" according to the EU classification scheme.

Executive summary:

Eye irritation was assessed in a group of New Zealand white rabbits. 0.1 ml undiluted 2,4,4-trimethylpentene was instilled in the conjunctival sac and animals were observed for up to 8 days. Instillation caused slight initial pain in one animal but there was no initial pain response in the other 2 animals. Injection of the conjunctival blood vessels was present in each animal during the first 72 hours after instillation and iritis was present in one animal at the 1 hour assessment only. All signs of eye irritation had resolved by day 8. The mean values for ocular lesions at 24, 48 and 72 hours after instillation did not equal or exceed the EU limit values for classification of 2,4,4-trimethylpentene as "irritant to the eye".