Benzoic acid, 2-hydroxy-, C14-18-alkyl derivs.

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6 February to 12 March 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The study was conducted prior to the development and use of the LLNA protocol

Test material

Test material information

Constituent 1

Reference substance name:

Benzoic acid, 2-hydroxy-,C14-18 alkyl derivs.

EC Number:

931-472-4

Cas Number:

182700-89-6

IUPAC Name:

Benzoic acid, 2-hydroxy-,C14-18 alkyl derivs.

Constituent 2

Reference substance name:

605-976-7

EC Number:

605-976-7

IUPAC Name:

605-976-7

Test material form:

liquid: viscous

Details on test material:

- Physical state: opaque, pale brown viscous liquid
- Stability under test conditions: not given, the responsibility of the sponsor
- Storage condition of test material: ambient temperature, protected from light, under nitrogen in a flameproof cabinet
- Other: flash point >32 °C; density at 20 °C 0.92 kg/L; viscosity at 20 °C 5 mm²/s

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 6 to 8 weeks
- Weight at study initiation: control animals 323 to 396 g, test animals 317 to 412 g on day 1
- Housing: no more than 5 animals/sex/cage in suspended stainless steel cages with grid floors and tops
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 6 days but not more than 16 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 23
- Humidity (%): 37 to 66
- Air changes (per hr): at least 10; without recirculation
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

propylene glycol

Induction 2

Concentration / amount:

First (intradermal) induction: 5 % v/v in propylene glycol or 5 % v/v in propylene glycol in FCA
Second (topical) induction: 10 % v/v in propylene glycol
Topical challenge: 1 or 5 % v/v in propylene glycol

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

propylene glycol

Challenge 2

Concentration / amount:

First (intradermal) induction: 5 % v/v in propylene glycol or 5 % v/v in propylene glycol in FCA
Second (topical) induction: 10 % v/v in propylene glycol
Topical challenge: 1 or 5 % v/v in propylene glycol

No. of animals per dose:

Test group: 10 animals/sex, control group: 5 animals/sex

Details on study design:

RANGE FINDING TESTS: Intradermal and topical range finding studies were conducted. Four guinea-pigs received 6 intradermal injections of 0.1 mL of 3 concentrations of the test material in propylene glycol and three concentrations of the test material in propylene glycol and an emulsion of FCA into the skin overlying the scapulae. Two guinea-pigs received the maximum practicable concentration in each medium and two dilutions (10, 30 or 50 % v/v). The other two animals received three lower concentrations in each medium (1, 3 or 5 % v/v). Reactions to treatment were assessed approx. 24 and 48 h and 7 days after injection. For the topical induction range finding test, two guinea-pigs were subjected to a single intradermal injection of 0.1 mL FCA at least 5 days before topical application. The hair was removed from both flanks of the animals and topical application of 0.25 mL of the maximum practicable concentration of the test material and three lower concentrations in propylene glycol (10, 30, 50 % or as supplied) was administered to the four test sites on each guinea-pig, on a 2 x 2 cm absorbent patch which was covered by an occlusive dressing for 48 h. Reactions were assessed approx. 24 and 48 hr and 7 days after removal of the dressings. For the topical challenge range finding test, 3 guinea-pigs received a single intradermal injection of 0.1 mL FCA at least 20 days before topical application. The hair was removed from both flanks of the animals and topical application of 0.03 mL of 4 concentrations of the test material in propylene glycol (1, 3, 5 or 10 % v/v) was administered to the four test sites on each animal, applied on a 1 cm diameter absorbent patch which was covered by an occlusive dressing for 24 h. Reactions were assessed approx. 24 and 48 h after removal of the dressings.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: about 10 days
- Test groups: test material in propylene glycol or propylene glycol and FCA for the injection phase, test material in propylene glycol for the topical phase
- Control group: FCA, propylene glycol or propylene glycol in FCA
- Site: intradermal injections on the dorsal surface, parallel to the spinal column and near to the periphery of the dermal induction site overlying the scapulae
- Frequency of applications: one intradermal injection exposure on day 1 and one topical exposure on day 8
- Duration: 10 days (total); 2 days (topical)
- Concentrations: intradermal injection of 5 % v/v test material, topical application of 10 % v/v test material.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day of challenge: 22
- Exposure period: 24 h
- Test groups: test substance in propylene glycol or propylene glycol alone
- Control group: test substance in propylene glycol or propylene glycol alone
- Site: right flank for test substance, left flank for vehicle
- Concentrations: 1 and 5 % v/v
- Evaluation (hr after challenge): 24 and 48 h after removal of the occlusive dressings

OTHER: test sites were wiped with a paper tissue moistened with propylene glycol immediately after the removal of the bandage. Significant erythematous reactions were considered as Grade 1 or above and barely perceptible erythema (grade ±) was not considered to be a significant or conclusive indication of delayed contact hypersensitivity.

Challenge controls:

See Details on study design (above)

Positive control substance(s):

no

Results and discussion

Positive control results:

this OECD guideline does not involve a positive control substance, merely the use of FCA as a potentiator/exacerbator of the reaction

In vivo (non-LLNA)

Results

Results 1

Reading:

other: M&K test does not use positive control

Hours after challenge:

0

Group:

positive control

Dose level:

N/A

No. with + reactions:

0

Total no. in group:

0

Results 2

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5%

No. with + reactions:

7

Total no. in group:

20

Clinical observations:

Severe erythema with eschar formation in 2, slight erythema in 5

Results 3

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5%

No. with + reactions:

10

Total no. in group:

20

Clinical observations:

Severe erythema and eschar formation in 2 with one also showing exfoliation, slight erythema in 8 with 6 showing exfoliation

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5%

No. with + reactions:

0

Total no. in group:

10

Results 5

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1%

No. with + reactions:

0

Total no. in group:

20

Results 6

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

1%

No. with + reactions:

0

Total no. in group:

10

Results 7

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0% (vehicle control)

No. with + reactions:

0

Total no. in group:

20

Any other information on results incl. tables

At induction, intradermal injection of the test material at 5 % in propylene glycol caused slight erythema in all animals and pallor in nearly half the males, while 5 % in propylene glycol with FCA caused moderate erythema in all animals and pallor in 8/20 animals. Intradermal injection of FCA alone caused moderate erythema in all guinea-pigs tested. Topical application of 10 % in propylene glycol caused exfoliation in all animals and occasional eschar formation while propylene glycol alone caused no dermal reaction. Throughout the experimental period, the animals remained in overt good health and achieved anticipated overall bodyweight gains.

Overall, 11 (55 %) of the 20 test group guinea pigs (6 males and 5 females) gave a dermal response of grade 1 or more when assessed 24 and 48 h after removal of the challenge dose.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

The test material caused delayed contact hypersensitivity in the guinea-pig Maximisation test.

Executive summary:

In a GLP study conducted according to OECD Guideline 406 and EU Method B.6, ten male and ten female Dunken-Hartley guinea pigs were induced, in a Magnusson and Kligman maximisation test, with an intradermal injection of 5 % test material (approximately 65 % active substance, 35 % xylene) in propylene glycol (with or without Freunds Complete Adjuvant (FCA)), followed seven days later by a 48-h occlusive dermal application of 10 % test material in proplyene glycol to the closely clipped dorsa. Five male and five female animals served as the controls and were treated with FCA alone, propylene glycol alone, or FCA and propylene glycol together. All animals were challenged, on day 22, with a 24-h occluded application of propylene glycol, or 1 or 5 % test material in propylene glycol. These test sites were assessed 24 and 48 h after removal of the dressing.

Challenge application of 5 % test material in propylene glycol gave rise to a significant dermal response (slight erythema or a more marked reaction) in seven and ten of the 20 animals assessed 24 and 48 h after removal of the challenge patch, respectively. Overall, eleven test (55 %) and none of the control animals responded positively to challenge, whereas challenge with the 1 % concentration, or propylene glycol alone, caused no significant response. It is concluded that, under the conditions of this study, repeated administration of the test material caused delayed contact hypersensitivity in guinea pigs.