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Diss Factsheets

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
1989-03-07 to 1989-04-01
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Read-across from guideline study, tested with the source substance monolauryl phosphate. In accordance to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

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

Test material

Constituent 1
Reference substance name:
Monolauryl phosphate
IUPAC Name:
Monolauryl phosphate
Constituent 2
Reference substance name:
2627-35-2 (Monolauryl phosphate)
IUPAC Name:
2627-35-2 (Monolauryl phosphate)
Details on test material:
- Physical state: solid
- Analytical purity: not given in test report, but according to supplier 99.5%

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: no data
- Weight at study initiation: 386 – 479 g
- Housing: no data
- Diet (e.g. ad libitum): vitamin C-enriched guinea-pig diet F.D.1 ad libitum, hay was given weekly
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca 21°C
- Humidity (%):30-70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 1989-02-21 To: 1989-04-01

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
intradermal injection: 0.25%
epicutaneous induction: 12.5%
challenge: 0.5%, 0.25%
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
intradermal injection: 0.25%
epicutaneous induction: 12.5%
challenge: 0.5%, 0.25%
No. of animals per dose:
10 control animals
20 test animals (0.5% was applied to an anterior site; 0.25% to a posterior site of the same animals)
Details on study design:
RANGE FINDING TESTS:
The intradermal and topical irritancy of a range of dilutions of the test substance was investigated to identify (a) irritant test substance concentrations suitable for the induction phase of the main study and (b) non-irritant concentrations by the topical route of administration for the challenge phase.
Concentrations for intradermal injection (w/w in water for irrigation): 10%, 7.5%, 5%, 2.5%, 1%, 0.5%, 0.25%, 0.1%
Concentrations for topical application (w/w in water for irrigation): 50%, 30%, 20%, 15%, 12.5%, 10%, 5%, 1%

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal injection
A 4 x 6 cm area of dorsal skin on the scapular region of the guinea-pig was clipped free of hair with electric clippers. Three pairs of intradermal injections (0.1 mL) were made simultaneously into this area:
1. Freund's complete adjuvant diluted with an equal volume of water for irrigation
2. test substance 0.25% w/w in water for irrigation
3. test substance 0.25% w/w in a 50 : 50 mixture of Freund's complete adjuvant and water for irrigation

Topical application
One week after the injections, the same 4 x 6 cm interscapular area was clipped and shaved free of hair.
A 2 x 4 cm patch of Whatman No. 3 paper was saturated with the test substance, 12.5% w/w in distilled water. The patch was placed on the skin and covered by a length of impermeable plastic adhesive tape. This in turn was firmly secured by elastic adhesive bandage. The dressing was left in place for 48 h.

Control animals
Similar treatment, without test substance


B. CHALLENGE EXPOSURE
Test and control animals, topical application
The test and control animals were challenged topically two weeks after the induction period using the test substance in concentrations of 0.5% and 0.25% w/w in distilled water.
Hair was removed by clipping and then shaving from an area on the left flank of each guinea-pig. A 2 x 2 cm patch of Whatman No. 3 paper was saturated with approximately 0.2 mL of the test substance 0.5% w/w in distilled water and applied to an anterior site on the flank. The test substance in a concentration of 0.25% w/w in distilled water was applied in a similar manner to a posterior site. The patches were sealed with impermeable plastic adhesive tape to the flank for 24 h.

READING CHALLENGE REACTIONS
24, 48 and 72 h after removal of the patches
Scoring according to Magnusson and Kligman
Challenge controls:
Challenge exposure in control: 0.25% and 0.5% of the test substance
Positive control substance(s):
yes
Remarks:
formalin

Results and discussion

Positive control results:
The last periodic use of a positive control substance (formalin) with the acceptable level of response in the test animals was performed on January 10, 1989.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
negative control
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
0.25%, 0.5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
none
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 0.25%, 0.5%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: other: CLP, EU GHS (Regulation (EC) No 1272/2008)
Conclusions:
In this study monolauryl phosphate is not a dermal sensitiser.
Executive summary:

In a dermal sensitization study according to OECD TG 406 with Monolauryl phosphate, Dunkin-Hartley guinea pigs were tested using the method of Magnusson and Kligman. Positive control substance was formalin.

For intradermal induction a concentration of 0.25% was used. The test concentration used for epicutaneous induction (12.5%) was irritating. Thus, no pretreatment before epicutaneous induction was necessary. 24 hours after intradermal induction a 12.5% dilution of the test substance was applied and covered by occlusive dressing for 48 hours. Two test substance concentrations, 0.25% and 0.5%, were used for challenge (24 h, covered by occlusive dressing).

 

At challenge no visible changes of the treated skin sites (no erythema and no edema) were observed in test or control animals at any time point (24 h, 48 h, 72 h after removal of the patches).

  

In this study Monolauryl phosphate is not a dermal sensitizer.