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EC number: 200-915-7 | CAS number: 75-91-2
Skin sensitisation
Administrative data
- Endpoint:
- skin sensitisation: in vivo (non-LLNA)
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2001
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Guideline study performed under GLP standards
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 001
- Report date:
- 2001
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 406 (Skin Sensitisation)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method B.6 (Skin Sensitisation)
- Deviations:
- no
- GLP compliance:
- yes
- Type of study:
- guinea pig maximisation test
- Justification for non-LLNA method:
- Study conducted according to OECD Guideline 406 for skin sensitisation that predates adoption of OECD 429 in 2010.
Test material
- Reference substance name:
- tert-butyl hydroperoxide
- EC Number:
- 200-915-7
- EC Name:
- tert-butyl hydroperoxide
- Cas Number:
- 75-91-2
- Molecular formula:
- C4H10O2
- IUPAC Name:
- 2-methylpropane-2-peroxol
- Details on test material:
- Aqueous solution of TBHP (tertiary butyl hydroperoxide solution (70%))
- TBHP content 70%
- Physical state: clear colourless liquid
- Lot/batch No.: SGS REF 534326
Constituent 1
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, England
- Age at study initiation: circa 3 weeks
- Weight at study initiation: 215 - 262g
- Housing: in a mobile battery, containing 6 cages; maximal 10 animals per cage.
- Diet (e.g. ad libitum): Standard laboratory diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum.
- Acclimation period: 7 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 C
- Humidity (%): 30 - 70% (occasionally up to 100% for a short period, because of wet cleaning of the room or meteorological circumstances).
- Air changes (per hr): ca. 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours light/12hours dark cycle.
IN-LIFE DATES: From: 26 June 2001 To: 20 July 2001
Study design: in vivo (non-LLNA)
Inductionopen allclose all
- Route:
- intradermal and epicutaneous
- Vehicle:
- physiological saline
- Concentration / amount:
- 10 male guinea pigs; induction with intradermal injection on day 1 of Freunds Complete Adjuvant (FCA) 1:1 diluted with isotonic saline, a 1% test dilution of TBHP-70 in physiological saline and 1% test dilution of TBHP in FCA followed by topical induction on day 8 with 30% TBHP; challenge 14 days after with 3% TBHP (Day 22).
Challengeopen allclose all
- Route:
- epicutaneous, semiocclusive
- Vehicle:
- physiological saline
- Concentration / amount:
- 10 male guinea pigs; induction with intradermal injection on day 1 of Freunds Complete Adjuvant (FCA) 1:1 diluted with isotonic saline, a 1% test dilution of TBHP-70 in physiological saline and 1% test dilution of TBHP in FCA followed by topical induction on day 8 with 30% TBHP; challenge 14 days after with 3% TBHP (Day 22).
- No. of animals per dose:
- 15 male guinea pigs were randomly divided into 2 groups, one test group of 10 males and one control group of 5 males.
- Details on study design:
- RANGE FINDING TESTS:
The irritation response to intradermal injection of various concentrations of the test substance was examined in 2 guinea pigs. Amounts of 0.1 mL of the selected concentrations were applied by intradermal injection. 24 hours post injection, animals were examined for signs of irritation. A concentration causing slight to moderate irritation but otherwise well-tolerated by the animals (1% Aq. TBHP-70) was chosen for intradermal injection in the induction phase of the main study.
The irritation reponse to topical treatment of various concentrations of the test substance was examined in 2 other guinea pigs. Patches were loaded with the test material and placed on the clipped skin of each animal and covered with a piece of hypoallergenic paper bandage that was secured by the elastic adhesive bandage wound around the torso of the animal. The dressing was left in place for 24 hours. 24-48 after removal of the dressing, the animals were examined for signs of skin irritation. A concentration causing slight to moderate skin irritation is usually chosen for topical induction and a non-irritant concentration for topical challenge.
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 10
- Exposure period: Topical induction - 48 hour exposure
- Test groups: 1 (10 animals)
- Control group: 1 (5 animals)
- Site: Dorsal skin
- Duration: Topical induction for 48 hours then topical challenge on day 14.
- Concentrations: 1% TBHP-70
B. CHALLENGE EXPOSURE
- No. of exposures: 10
- Day(s) of challenge: 22
- Exposure period: Topical challenge - 24 hour exposure
- Test groups: 1 (10 animals)
- Control group: 1 (5 animals)
- Site: Dorsal skin
- Concentrations: 3% test concentration of TBHP-70
- Challenge controls:
- Physiological saline
- Positive control substance(s):
- yes
- Remarks:
- Formaldehyde
Results and discussion
- Positive control results:
- Challenge treatment with 10% and 3% test dilution of formaldehyde (37%) induced positive reactions in 100% and 60% of the test animals respectively.
In vivo (non-LLNA)
Resultsopen allclose all
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- test chemical
- Dose level:
- 3% TBHP-70
- No. with + reactions:
- 6
- Total no. in group:
- 10
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 3% TBHP-70. No with. + reactions: 6.0. Total no. in groups: 10.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- test chemical
- Dose level:
- 3% TBHP-70
- No. with + reactions:
- 6
- Total no. in group:
- 10
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 3% TBHP-70. No with. + reactions: 6.0. Total no. in groups: 10.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- negative control
- Dose level:
- negative control
- 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: negative control. No with. + reactions: 0.0. Total no. in groups: 5.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- negative control
- Dose level:
- negative control
- 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: negative control. No with. + reactions: 0.0. Total no. in groups: 5.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- positive control
- Dose level:
- 3% formaldehyde
- No. with + reactions:
- 3
- Total no. in group:
- 5
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 3% formaldehyde. No with. + reactions: 3.0. Total no. in groups: 5.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- positive control
- Dose level:
- 3% formaldehyde
- No. with + reactions:
- 3
- Total no. in group:
- 5
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 3% formaldehyde. No with. + reactions: 3.0. Total no. in groups: 5.0.
- Reading:
- 1st reading
- Hours after challenge:
- 24
- Group:
- positive control
- Dose level:
- 10% formaldehyde
- No. with + reactions:
- 4
- Total no. in group:
- 5
- Remarks on result:
- other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 10% formaldehyde. No with. + reactions: 4.0. Total no. in groups: 5.0.
- Reading:
- 2nd reading
- Hours after challenge:
- 48
- Group:
- positive control
- Dose level:
- 10% formaldehyde
- No. with + reactions:
- 5
- Total no. in group:
- 5
- Remarks on result:
- other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 10% formaldehyde. No with. + reactions: 5.0. Total no. in groups: 5.0.
Any other information on results incl. tables
Clinical observations:
Induction
Intradermal injections caused the following skin reactions:
1) In test animals:
- FCA/saline (1:1): moderate erythema
- selected test concentration: no skin reactions
- selected test concentration in FCA/diluent (1:1): moderate erythema
2) Control animals
- FCA/saline (1:1): moderate erythema
- vehicle: no skin reactions
- FCA/diluent (1:1): moderate erythema
Challenge
After the challenge treatment with the 3% test concentration of Aq. TBHP-70, slight moderate or severe erythema was observed in six test animals at 24 hours after challenge. At 48 hours after challenge, the 6 test animals showed moderate or severe erythema at the test site. The controls did not show any skin reactions.
Table 1 Skin scores in the test group (challenged with 3% TBHP-70).
| Skin scores obtained 24 and 48 hours after removal of the dressing. | ||
| Animal No. | 24 hours | 48 hours |
| Control group | ||
| 22 | 0 | 0 |
| 24 | 0 | 0 |
| 26 | 0 | 0 |
| 28 | Sacrified in extremis, unrelated to test article application | |
| 30 | 0 | 0 |
| Test group | ||
| 2 | 1 | 2 |
| 4 | 2 | 3 |
| 6 | 2 | 3 |
| 8 | 0 | 0 |
| 10 | 3 | 3 |
| 12 | 0 | 0 |
| 14 | 2 | 2 |
| 16 | 0 | 0 |
| 18 | 2 | 3 |
| 20 | 0 | 0 |
Applicant's summary and conclusion
- Interpretation of results:
- sensitising
- Remarks:
- Migrated information
- Conclusions:
- Aq. TBHP-70 caused skin sensitisation reactions in the test Guinea pigs. The induction and challenge regime employed corresponded to to TBHP treatment at 0.7% and 2.1% (induction) and 21% (challenge). It is therefore concluded that TBHP caused delayed contact sensitisation in Guinea pigs and must be considered to be a skin sensitiser.
- Executive summary:
TBHP caused delayed contact sensitisation in Guinea pigs and must be considered to be a skin sensitiser. Under EC Regulation 1272/2008, TBHP is classified as a skin sensitizer Category 1A.
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