2,2,4,4-tetramethylcyclobutane-1,3-diol, mixed isomers

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 26- February 25, 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study followed OECD protocol 406 and was conducted under various GLP assurances

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

The protocol requires an evaluation of the dose site be performed at approx. 48 hs after each application. Do to a snowstorm emergency, the 48-hour evaluations for the 3rd induction could not be performed until approx 73 hrs after application.

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

study was done prior to effective date that restrictions on in vivo testing were implemented

Test material

Test material information

Constituent 1

Reference substance name:

2,2,4,4-tetramethylcyclobutane-1,3-diol, mixed isomers

EC Number:

221-140-0

EC Name:

2,2,4,4-tetramethylcyclobutane-1,3-diol, mixed isomers

Cas Number:

3010-96-6

Molecular formula:

C8H16O2

IUPAC Name:

2,2,4,4-tetramethylcyclobutane-1,3-diol

Details on test material:

The test substance, identified as 2,2,4,4-tetramethyl-1,3-cyclobutanediol, Lot #X29601-54-5, consisted of white crystals and was stored at room
temperature. Prior to use, the test substance was ground with a coffee mill (Cuisinart/Model #DCG-20). Purity was noted to be 99.6%.

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

male

Details on test animals and environmental conditions:

Number of Animals: 34
Number of Groups: 3
Number of Animals per Group:
Preliminary Irritation Group: 4
Test Group: 20
Naive Control Group: I 0
Sex: Male
Species/Strain: Guinea pigs/Hartley albino.
Age/Body weight Preliminary Irritation Group: Young adult
Test and Naive Control Groups: Young adult/337-408 grams at experimental start.
Source: Received from Elm Hill Breeding Labs, Chelmsford, MA on January 13 and
February 3, 2006 (Preliminary Irritation Group) and January 20, 2006 (Test and Naive
Control Groups).
Housing: The animals were group housed in suspended stainless steel caging with mesh floors or plastic perforated bottom caging. Litter paper
was placed beneath the cage and was changed at least three times per week.
Animal Room Temperature Range: 19-22°C
Photoperiod: J2 .. hour light/dark cycle
Acclimation Period: 7-13 days
Food: Pelleted Purina Guinea Pig Chow #5025
Water: Filtered tap water was supplied ad-libitum by an automatic water dispensing system.

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

other: an occlusive 25 mm Hill Top Chamber

Vehicle:

other: mineral oil

Induction 2

Concentration / amount:

75% w/w

Challenge

Challenge 1

Route:

other: an occlusive 25 mm Hill Top Chamber

Vehicle:

other: mineral oil

Challenge 2

Concentration / amount:

75% w/w

No. of animals per dose:

20

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
Once each week for three weeks, four-tenths of a gram of a 75% w/w mixture of the ground test substance in mineral oil was applied to the left side of each test animal using an occlusive 25 mm Hill Top Chamber. The chambers were secured in place and wrapped with non-allergenic Durapore
adhesive tape to avoid dislocation of the chambers and to minimize loss of the test substance. After the 6-hour exposure period, the chambers
were removed and the test sites were gently cleansed of any residual test substance. Approximately 24 and 48 or 73 hours after each induction
application, readings were made of local reactions (erythema).

B. CHALLENGE EXPOSURE
Twenty-seven days after the first induction dose, four-tenths of a milliliter of a 38% w/w mixture of the ground test substance in mineral oil (HNIC)
was applied to a naive site on the right side of each animal as a challenge dose, using the procedures described above. These sites were evaluated for a sensitization response (erythema) approximately 24 and 48 hours after the challenge application.

Challenge controls:

In addition to the test animals, 10 guinea pigs from the same shipment were maintained under identical environmental conditions and were treated
with the test substance (HNIC) at challenge only. These animals constituted the "naive control" group.

Positive control substance(s):

yes

Remarks:

The procedures used in this study were validated using alpha-Hexylcinnamaldehyde Technical (HCA) as a positive control substance.

Study design: in vivo (LLNA)

Vehicle:

other:

Results and discussion

Positive control results:

Historical Positive Control Animals (75% w/w mixture of HCA in mineral oil): Three of ten positive control animals exhibited signs of a sensitization
response (faint to moderate erythema [1-2]) 24 and 48 hours after challenge. Very faint erythema (0.5) was noted for four other sites after challenge.

In vivo (non-LLNA)

Results

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

38%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 38%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

Based on these findings and on the evaluation system used, 2,2,4,4-Tetramethyl-1,3-cyclobutanediol is not considered to be a contact sensitizer.

Executive summary:

A dermal sensitization test was conducted with guinea pigs using the Beuhler Method to determine the potential for

2,2,4,4 -tetramethyl-1,3-cyclobutanediol to produce sensitization after repeated topical applications. A 75% w/w mixture of the test substance in mineral oil was topically applied to twenty healthy test guinea pigs, once each week for a three-week induction period. Twenty-seven days after the first induction dose, a challenge dose of the test substance at its highest non-irritating concentration (HNIC, determined in the preliminary irritation screen to be a 38% w/w mixture in mineral oil) was applied to a naive site on each guinea pig. A naive control group (ten animals) was maintained under the same environmental conditions and treated with the test substance at challenge only. Approximately 24 and 48 hours after each induction and challenge dose, the animals were scored for erythema. Results indicated 0/20 animals showing evidence of sensitization.