Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic and n-heptanoic acids

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 Dec 1998 - 01 February 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

adopted in 1992

Deviations:

yes

Remarks:

no analytical purity reported

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

yes

Remarks:

no analytical purity reported

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

draft

Deviations:

yes

Remarks:

no analytical purity reported

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom, UK

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The validity of the LLNA was endorsed by ECVAM (European Centre for the Validation of Alternative Methods) on 21 March 2000.

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

444-000-2

EC Name:

-

Cas Number:

647028-25-9

Molecular formula:

This is a UVCB so NA

IUPAC Name:

3-[3-(pentanoyloxy)-2,2-bis[(pentanoyloxy)methyl]propoxy]-2,2-bis[(pentanoyloxy)methyl]propyl pentanoate 3-{3-[(3,5,5-trimethylhexanoyl)oxy]-2,2-bis({[(3,5,5-trimethylhexanoyl)oxy]methyl})propoxy}-2,2-bis({[(3,5,5-trimethylhexanoyl)oxy]methyl})propyl 3,5,5-trimethylhexanoate

Details on test material:

- Name of test material (as cited in study report): only trade name given
- Physical state: straw coloured liquid
- Analytical purity: UVCB tested
- Storage condition of test material: at room temperature in darkness

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: David Hall Limited, Burton-on-Trent, Staffordshire, UK
- Age at study initiation: 8–12 weeks
- Weight at study initiation: 335–440 g
- Housing: animals were housed individually or in pairs in solid-floor polypropylene cages furnished with woodflakes.
- Diet: Guinea Pig FD1 (Special Diets Services Limited, Witham, UK), ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-22
- Humidity (%): 44-57
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

arachis oil

Induction 2

Concentration / amount:

Induction: intradermal 25%; epicutaneous 100%
Challenge: 75 and 100%

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

arachis oil

Challenge 2

Concentration / amount:

Induction: intradermal 25%; epicutaneous 100%
Challenge: 75 and 100%

No. of animals per dose:

5 (controls), 10 (in test groups)

Details on study design:

RANGE FINDING TESTS
INDUCTION EXPOSURE (INTRADERMAL)
Four guinea pigs were intradermally injected with 0.1 mL of 1, 5, 10 and 25% (w/v) of the test material in arachis oil BP. The grade of erythema at the injection site was assessed approximately 24, 48 and 72 h and 7 days after injection according to the Draize scale. The highest concentration that caused only mild to moderate skin irritation, and was well tolerated systemically, was selected for the intradermal induction phase of the main study.
INDUCTION EXPOSURE (TOPICAL)
Two guinea pigs, previously injected with Freud’s Complete Adjuvant (eighteen days earlier), were treated with the undiluted test item and 75, 50 and 25% (v/v) of the test item in arachis oil BP for 48 h (clipped flanks; occlusive dressing). The degree of erythema and edema was assessed approximately 1, 2 and 48 h after dressing removal. The highest concentration producing only mild to moderate dermal irritation was selected for the topical induction stage of the main study.
CHALLENGE
Two guinea pigs were treated with undiluted test material and 75, 50 and 25% (v/v) in arachis oil BP applied to the clipped flanks under occlusive conditions for an exposure period of 24 h. The highest non-irritant concentration of the test material and one lower concentration were selected for the topical challenge phase of the main study. The treated skin was evaluated for erythema and edema scores were observed approximately 1, 24, and 48 h after dressing removal.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and epicutaneous, respectively)
- Exposure period: single injection (intradermal) and 48 h (epicutaneous)
- Test groups:
Intradermal (3 pairs of injections):
Injection 1: a 1:1 mixture (v/v) FCA/water
Injection 2: test substance in arachis oil BP
Injection 3: test substance in a 1:1 mixture (v/v) FCA/water

Epicutaneous: test substance in arachis oil BP

- Control group:
Intradermal (3 pairs of injections)
Injection 1: a 1:1 mixture (v/v) FCA/water
Injection 2: arachis oil BP
Injection 3: arachis oil BP at 50% in a 1:1 mixture (v/v) FCA/water
Epicutaneous: arachis oil BP

- Site: shoulder region (intradermal + epicutaneous)
- Frequency of applications: every 7 days
- Duration: Days 0-7
- Concentrations: intradermal 25%, epicutaneous 100%

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 20
- Exposure period: 24 h
- Test groups: test substance
- Control group: test substance
- Site: right flank (test substance 100%) and left flank (test substance 75%)
- Concentrations: 75 and 100%
- Evaluation (hr after challenge): 24 and 48 h after patch removal

Positive control substance(s):

yes

Remarks:

2-Mercaptobenzothiazole (Intradermal induction concentration of 10% in arachis oil, topical induction concentration of 50% in acetone/PEG400; challenge concentration of 50 and 25% in acetone/PEG400)

Results and discussion

Positive control results:

At least two tests per year are performed in the laboratory. 100% of the animals in the test group (10 males) showed incidence of sensitisation.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

induction: 0%; challenge: 100%

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: induction: 0%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 5.0.

Results 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

induction: 25%; challenge: 75 and 100%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: induction: 25%; challenge: 75 and 100%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Results 3

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

induction: 0%; challenge: 100%

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: induction: 0%; challenge: 100%. No with. + reactions: 0.0. Total no. in groups: 5.0.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

induction: 25%; challenge: 75 and 100%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: induction: 25%; challenge: 75 and 100%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Results 5

Reading:

1st reading

Group:

positive control

Dose level:

Intradermal induction concentration of 10% in arachis oil, topical induction concentration of 50% in acetone/PEG400; challenge concentration of 50 and 25% in acetone/PEG400

No. with + reactions:

10

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Conclusions:

CLP: not classified