1-isopropyl-2,2-dimethyltrimethylene diisobutyrate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

a single 24 hour application followed by a 14 day observation period

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Reliable without restriction; study conducted according to OECD 402 guideline and GLPs.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Propanoic acid, 2-methyl-, 1,1'-[2,2-dimethyl-1-(1-methylethyl)-1,3-propanediyl] ester

IUPAC Name:

Propanoic acid, 2-methyl-, 1,1'-[2,2-dimethyl-1-(1-methylethyl)-1,3-propanediyl] ester

Constituent 2

Reference substance name:

1-isopropyl-2,2-dimethyltrimethylene diisobutyrate

EC Number:

229-934-9

EC Name:

1-isopropyl-2,2-dimethyltrimethylene diisobutyrate

Cas Number:

6846-50-0

Molecular formula:

C16H30O4

IUPAC Name:

trimethoxy[3-(oxiran-2-ylmethoxy)propyl]silane

Constituent 3

Reference substance name:

2,2,4-Trimethylpentanediol-1,3-diisobutyrate

IUPAC Name:

2,2,4-Trimethylpentanediol-1,3-diisobutyrate

Constituent 4

Reference substance name:

Texanol isobutyrate; TXIB

IUPAC Name:

Texanol isobutyrate; TXIB

Details on test material:

-Test substance (name as cited in study report): Eastman TXIB
-Source of test material: Eastman Chemical Company
-Purity: >98%
-Production date: 4/26/07
-Date of receipt: 7/26/07
-Stability: 1 year
-Storage: Room temperature and humidity
-Description: Clear liquid
-Specific gravity: 0.92

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test animals:
-Strain: New Zealand White Rabbits (Millbrook Breeding Labs, Amherst, MA)
-Date of receipt: 8/08/07
-Age: 3 months
-Sex: 5 males and 5 females
-Body weight: 2.4-2.9 kg (males) and 2.4-2.8 kg (females)
-Acclimation period: at least 7 days
-Identification: uniquely numbered metal ear tag
-Method of randomization: used standard methods; weight variation did not exceed +/-20% of the mean weight for each sex

Environmental Conditions:
-Housing: 1 rabbit per suspended wire cage (bedding placed beneath the cage changed at least 3 times weekly)
-Feed: Fresh PMI Rabbit Chow (Diet 5321) provided daily
-Water: water available ad libitum
-Light cycle: 12:12 light:dark

In Life Dates:
-Study initiation: 8/21/07
-Study termination: 9/04/07

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

The day prior to test substance administration, the dorsal area of the trunk of each animal was clipped free of hair. The area was approximately 10% of the body surface and remained intact. A single dose of 2000 mg/kg bw of the test substance was applied over a 4-ply porous gauze dressing measuring 10 x 15 cm and the torso was wrapped in a semi-occlusive manner and secured with non-irritating tape. After a 24 hour exposure period, the cuffs and wrappings were removed. Residual test material was removed with paper towels soaked in copious tap water.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5 rabbits per sex

Control animals:

no

Details on study design:

Method is an in vivo study using 5 rabbits/sex. A single dose of 2000 mg/kg bw of the test substance was held in contact with the dorsal side of the animals under a semi-occlusive cuff for 24 hours. Animals were observed after exposure for the following:

Mortality – 2X/day for 14 days

Toxicity and pharmacological effects – 1 and 2 hours post dose; then 1X/day until termination

Dermal reactions - scored by the numerical Draize method at 24 hours postdose; then on Days 7 and 14. Skin was also evaluated for ulceration and necrosis or any evidence of tissue destruction.

Body weight – recorded pretest, weekly, and at death or termination in the survivors

Gross pathology - performed at study termination.

Statistics:

Statistical analyses were not performed.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Remarks on result:

other: All animals survived the 14-day observation period.

Mortality:

No mortality was observed in the study.

Clinical signs:

other: Instances of diarrhea, few feces and soiling of the anogenital area were noted during the observation period.

Gross pathology:

Necropsy results were normal in 3/5 males and 3/5 females. Abnormalities included small spleen in 1/5 males, slight or scattered red areas in the thymus of 1 male, and slight or scattered red areas in the pancreas of 1/5 males and 2/5 females.

Other findings:

Dermal Observations:
Day 1 – Erythema and edema were absent in 2/5 males and 1/5 females. Very slight erythema (Grade 1) was present in 1/5 males and 3/5 females while well defined erythema (Grade 2) was present in 1/5 females. Very slight edema (Grade 1) was present in 2/5 males and 1/5 females while slight edema (Grade 2) was present in 1/5 males and 1/5 females.

Day 7 – All males and 3/5 females were normal; 2/5 females had severe erythema (Grade 4) with flaking skin. One of the females had slight edema (Grade 2) while the other had very slight edema (Grade 1).

Day 14 – All animals were normal.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

2,2,4-Trimethyl-1,3-pentanediol diisobutyrate was not acutely toxic by the dermal route in rabbits under conditions used in this study. The dermal LD50 in rabbits was > 2000 mg/kg bw.

Based on an acute dermal LD50 value of > 2000 mg/kg bw in male and female rabbits, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate is not classified for Acute Toxicity by the dermal route under GHS. Based on an absence of significant target organ or other systemic effects, the test material is also not classified for Specific Target Organ Toxicity - Single Exposure under GHS.

Executive summary:

In an acute dermal toxicity study, 5 rabbits/sex were exposed to 2000 mg/kg bw of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate under semi-occlusive contact for 24 hours. No mortality or significant target organ effects were noted during the study and the oral LD50 was considered to be > 2000 mg/kg bw. Signs of irritation ranged from absent (erythema and edema) to well defined erythema and slight edema on Day 1. By Day 7, all males and 3 of 5 females appeared normal. The other 2 females had very slight or slight edema and severe erythema with flaking skin. On day 14, all rabbits appeared normal.  A body weight gain was noted for all animals over the 2-week observation period. Based on the results of this study, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate presents a low toxicity hazard upon skin contact under conditions of normal use.