Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

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:
key study
Study period:
1998-10-27 to 1998-12-04
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study conducted with the read-across substance (please refer to read-across statement).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

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
Test material form:
other: liquid
Details on test material:
- Molecular formula (if other than submission substance): C28H62NO4P (for a representative structure: Phosphoric acid, di(C8)ester, compds with C12 amine)
- Molecular weight (if other than submission substance): 507.76
- Smiles notation (if other than submission substance): CCCCCCCCCCCCN.O=P(O)(OCCCCCCCC)OCCCCCCCC
- InChl (if other than submission substance): InChI=1/C12H27N/c1-2-3-4-5-6-7-8-9-10-11-12-13/h2-13H2,1H3
- Substance type: organic (Alkylamine salt of alkyl phosphoric acid)
- Physical state: Clear yellow liquid
- Composition of test material, percentage of components: Data relating to the identity, purity and stability of the test material are the responsibility of the Sponsor
- Storage condition of test material: room temperature in the dark

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall, Newchurch, Staffs, UK.
- Age at study initiation: four to seven weeks
- Weight at study initiation: 249 to 366 g
- Housing: in groups of five in suspended metal cages with wire mesh floors
- Diet (e.g. ad libitum): ad libitum; A vitamin C enriched guinea-pig diet (Harlan Teklad 9600 FD2 SQC); Hay was given thrice weekly.
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 15.5 - 21
- Humidity (%): 30 - 78
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
coconut oil
Remarks:
Alembicol D
Concentration / amount:
Induction intradermal injection - 0.25 % v/v in Alembicol D
Induction topical application - as supplied
Topical challenge - 25 and 12.5 % v/v in Alembicol D
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
coconut oil
Remarks:
Alembicol D
Concentration / amount:
Induction intradermal injection - 0.25 % v/v in Alembicol D
Induction topical application - as supplied
Topical challenge - 25 and 12.5 % v/v in Alembicol D
No. of animals per dose:
Control animals: 10
Test animals: 20
Naive control animals (rechallenge): 10
Details on study design:
RANGE FINDING TESTS:
Additional eight animals from the same supplier were used for the preliminary investigations.
The intradermal and topical irritancy of a range of dilutions of the test substance was investigated to identify where possible (a) concentrations of the test substance that would produce irritation suitable for the induction phase of the main study and (b) a maximum non-irritant concentration by the topical route of administration for the challenge phase. The animals for the topical irritancy investigations were pre-treated with an intradermal injection of Freund’s complete adjuvant, 50 : 50 with water for irrigation (Ph.Eur.; sterile water for injection), approximately one week prior to the start of the preliminary investigations.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal injection and topical application)
- Exposure period: 48 hours (topical application)
- Test groups: A 40 x 60 mm 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 were made into a 20 x 40 mm area within the clipped area. One week after the injections, the same 40 x 60 mm interscapular area was clipped and shaved free of hair. A 20 x 40 mm patch of Whatman No. 3 paper was saturated with approximately 0.4 mL of the test material, as supplied. The patch was placed on the skin of the test animals and covered by a length of impermeable plastic adhesive tape (50 mm width “Blendem”). This in turn was firmly secured by elastic adhesive bandage (50 mm width “Elastoplast”) wound round the torso of the animal and fixed with ”Sleek” impervious plastic adhesive tape. The dressing was left in place for 48 hours.
- Control group: During the induction phase, the twenty control animals (10 control and 10 naive control) were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application.
- Site: 20 x 40 mm
- Frequency of applications: three pairs of intradermal injections
- Duration: approx. 23 days (intradermal injection (1 week), then topical application (48 hours), thereafter rest period (14 days)
- Concentrations (intradermal injections):
1) Freund’s complete adjuvant was diluted with an equal volume of water for irrigation (Ph.Eur.);
2) Test material, 0.25 % v/v in Alembicol D;
3) Test material, 0.25 % v/v in a 50 : 50 mixture of Freund’s complete adjuvant and Alembicol D.


B. CHALLENGE EXPOSURE
The test and first group of ten control animals (normal control) were challenged topically two weeks after the topical induction application using the test material, 25 and 12.5 % vlv in Alembicol D.
- No. of exposures: 2 (challenge and rechallenge)
- Day(s) of challenge: two weeks after the topical induction application (challenge); one week after challenge (rechallenge)
- Exposure period: 24 hours
- Test groups: Hair was removed by clipping and then shaving from an area on the left flank of each guinea-pig. A 20 x 20 mm patch of Whatman No. 3 paper was saturated with approximately 0.2 mL of the test material, 25 % v/v in Alembicol D and applied to an anterior site on the flank. The test material, 12.5 % v/v in Alembicol D was applied in a similar manner to the posterior site. The patches were sealed to the flank for 24 hours under strips of “Blenderm” covered by “Elastoplast” wound round the trunk and secured with “Sleek”. A second challenge application was made one week later. The method employed was similar to that described above with the exception that on this occasion the test material, 1 and 0.5 % v/v was applied to the left flank of all the control and test animals. For the second challenge the second group of ten control animals was used.
- Control group: treated in the same manner as test group.
- Site: 20 x 20 mm (anterior and posterior sites of the flank)
- Concentrations: 25 % and 12.5 % v/v in vehicle (challenge); 1 and 0.5 % v/v (rechallenge).
- Evaluation (hr after challenge): The challenge sites were evaluated 24 and 48 hours after removal of the patches. The site were also observed 72 hours after removal of the patches for the first challenge only.

OTHER: All animals were observed daily for signs of ill health or toxicity. The bodyweight of each guinea-pig on the main study was recorded on Day 1 (day of intradermal injections) and on the last day observations were made of dermal responses to the challenge application.
Challenge controls:
During the induction phase, the twenty control animals were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application. During the challenge and rechallenge phases, the test animals were treated in the same manner as the test animals: first ten control animals were used for challenge and second ten control animals (naive control) were used for rechallenge one week later.
Positive control substance(s):
yes
Remarks:
The sensitivity of the guinea-pig strain used is checked periodically at Huntingdon Life Sciences with known sensitisers hexyl cinnamic aldehyde (HCA), Benzocaine and 2-mercaptobenzothiazole (MBT).

Results and discussion

Positive control results:
Skin sensitization positive control study was performed to the Magnusson & Kligman method using guinea pig and a known weak/moderate sensitizer 2-Mercaptobenzothiazole (MBT). The following concentrations of MBT were administered:
Intradermal injection: 10 % wlv in Alembicol D
Topical application: 83.3% wlv in Alembicol D
Challenge application: 83.3 and 40% wlv in Alembicol D.
MBT produced evidence of skin sensitisation (delayed contact hypersensitivity) in all of the ten animals, thus confirming the sensitivity and reliability of the experimental technique.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
other: Freunds' treated controls
Dose level:
25 %
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: Freunds' treated controls. Dose level: 25 %. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
1st reading
Hours after challenge:
24
Group:
other: Freunds' treated controls
Dose level:
12.5 %
No. with + reactions:
8
Total no. in group:
10
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: Freunds' treated controls. Dose level: 12.5 %. No with. + reactions: 8.0. Total no. in groups: 10.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
other: Freunds' treated controls
Dose level:
25%
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
well-defined to moderate dermal reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: Freunds' treated controls. Dose level: 25%. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: well-defined to moderate dermal reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
other: Freunds' treated controls
Dose level:
12.5 %
No. with + reactions:
7
Total no. in group:
10
Clinical observations:
slight dermal reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: Freunds' treated controls. Dose level: 12.5 %. No with. + reactions: 7.0. Total no. in groups: 10.0. Clinical observations: slight dermal reactions.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
other: Freunds' treated controls
Dose level:
25 %
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
well-defined to moderate dermal reactions
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: other: Freunds' treated controls. Dose level: 25 %. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: well-defined to moderate dermal reactions.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
other: Freunds' treated controls
Dose level:
12.5 %
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
no reactions to slight dermal reactions
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: other: Freunds' treated controls. Dose level: 12.5 %. No with. + reactions: 3.0. Total no. in groups: 10.0. Clinical observations: no reactions to slight dermal reactions.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25 %
No. with + reactions:
20
Total no. in group:
20
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25 %. No with. + reactions: 20.0. Total no. in groups: 20.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
12.5 %
No. with + reactions:
20
Total no. in group:
20
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 12.5 %. No with. + reactions: 20.0. Total no. in groups: 20.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25 %
No. with + reactions:
20
Total no. in group:
20
Clinical observations:
well-defined to moderate dermal reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25 %. No with. + reactions: 20.0. Total no. in groups: 20.0. Clinical observations: well-defined to moderate dermal reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
12.5 %
No. with + reactions:
19
Total no. in group:
20
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 12.5 %. No with. + reactions: 19.0. Total no. in groups: 20.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
25 %
No. with + reactions:
20
Total no. in group:
20
Clinical observations:
well-defined to moderate dermal reactions
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 25 %. No with. + reactions: 20.0. Total no. in groups: 20.0. Clinical observations: well-defined to moderate dermal reactions.
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test chemical
Dose level:
12.5 %
No. with + reactions:
16
Total no. in group:
20
Clinical observations:
slight to well-defined dermal reactions
Remarks on result:
other: Reading: other: 3rd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 12.5 %. No with. + reactions: 16.0. Total no. in groups: 20.0. Clinical observations: slight to well-defined dermal reactions.
Reading:
rechallenge
Hours after challenge:
24
Group:
other: Freunds' treated controls (naive)
Dose level:
1 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: other: Freunds' treated controls (naive). Dose level: 1 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
24
Group:
other: Freunds' treated controls (naive)
Dose level:
0.5 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: other: Freunds' treated controls (naive). Dose level: 0.5 % . No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
48
Group:
other: Freunds' treated controls (naive)
Dose level:
1 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: other: Freunds' treated controls (naive). Dose level: 1 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
48
Group:
other: Freunds' treated controls (naive)
Dose level:
0.5 %
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: other: Freunds' treated controls (naive). Dose level: 0.5 %. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
1 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 1 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
0.5 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 0.5 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
1 %
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no dermal reactions
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 1 %. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no dermal reactions.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
0.5 %
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 0.5 %. No with. + reactions: 0.0. Total no. in groups: 20.0.

Any other information on results incl. tables

Based on the results of the preliminary investigations, the following concentrations the test material were selected:

Induction: intradermal injection: 0.25 % v/v in Alembicol D. This was the highest concentration that caused irritation but did not adversely affect the animals.

Induction topical application: as supplied, test material applied topically produced some irritation but did not adversely affect the animals.

Topical challenge: 25 and 12.5 % v/v in Alembicol D. From preliminary investigations 25 % v/v in Alembicol D was the highest concentration not giving rise to irritating effects.

Main study

Induction (intradermal injections):

Necrosis was recorded at sites receiving Freund’s Complete Adjuvant in test and control animals. Slight to well-defined irritation was seen in test animals at sites receiving the test material, 0.25 % v/v in Alembicol D and slight to well-defined irritation was observed in control animals receiving Alembicol D.

Induction (topical application):

Slight to well-defined erythema was observed in test animals following topical application with the test material, as supplied. Slight erythema was seen in two control guinea-pigs.

First challenge

Well-defined to moderate dermal reactions were seen in the test and control animals which precluded meaningful assessment of sensitization. A second challenge was performed using lower concentrations of the test material.

Table 1: Dermal reactions observed after the first challenge (Freund's treated controls)

Guinea-pig E = Erythema     Score    
number O = Oedema            
    24 Hours 48 Hours 72 Hours
    A P A P A P
4815 E 1 0 2 1 2 0
  0 1 0 1 0* 1* 0
4816 E 2 1 2 1 2 1
  0 2 0 2 0* 2 0*
4817 E 2 2 2 1 2 1
  0 1 1 2 1* 2# 0*
4818 E 2 1 3 1 3 0
  0 2 0 2 0* 2# 0*
4819 E 1 0 2 0 2 0
  0 1 0 1 0 1* 0
4820 E 2 1 2 0 2 0
  0 1 0 2 0 2# 0
4821 E 2 1 3 1 NP2 0
  0 1 0 2 1* 2# 0
4822 E 2 1 3 1 3 0
  0 1 0 2 0* 2# 0*
4823 E 2 1 3 1 2 1
  0 1 0 2# 0* # 0*
4824 E 2 1 3 0 2 0
  0 2 0 2 0 2# 0

Table 2: Dermal reactions observed after the first challenge application (Test animals)

Guinea-pig = Erythema     Score    
number = Oedema            
    24 Hours 48 Hours 72 Hours
    A P A P A P
4835 E NP2 1 NP3 1 NP3 1
  0 2 1 2 1# 2# 0*
4836 E 2   3 2 3 2
  0 2 1 2# 2# 2# 1*
4837 E NP2 1 NP3 2 NP2 1
  0 2 1 2 1* 2# 1*
4838 E NP2 1 NP3 0 NP3 0
  0 2 1 2 0 2# 0*
4839 E NP2 1 NP3 2 NP3 2
  0 1 1 2 2# 2 2#
4840 E NP2 1 NP3 1 NP2 1
  O 2 1 2 1* 1# 0*
4841 E NP2 I 3 1 NP2 1
  0 1 0 2# 1# 1# 0*
4842 E NP2 2 NP3 2 NP3 2
  0 2 2 2 2# 2 2#
4843 E 2 2 2 2 2# 1
  0 1 1 2# 1 2* 1*
4844 E 2 1 3 1 2 L1
  0 1 0 2# 1* 2# 0

Table 2 (continued): Dermal reactions observed after the first challenge application (Test animals)

Guinea-pig E = Erythema     Score    
number O = Oedema            
    24 Hours 48 Hours 72 Hours
    A P A P A P
4845 E  NP2 1 NP3 1 NP2 0
  O 2 0 2 1# 2# 0*
4846 E  NP2 1 NP3 1 NP2 1
  O 2 0 2 1* 2# 0*
4847 E  2 1 3 1 3 0
  O 2 0 2 1* 2* 0*
4848 E  NE2 2 3 2 2 1
  O 2 1 2 2# 3# 0*
4849 E  NP2 1 NP3 1 NP2 0
  O 2 1 2 1# 2# 0*
4850 E  2 1 2 1 2 1
  O 1 0 2# 1# 2# 0*
4851 E  2 2 3 2 2 1
  O 2 1 2 2# 2# 1*
4852 E  NP2 2 NP3 2# NP2 1
  O 1 1 2 1 2# 1#
4853 E  NP2 NP2 NP3 NP2 NP3 NP2
  O 2 2 2 2# 2 2#
4854 E  NP3 2 N 3 N 2
  O 2 2 3 2 3 2

N Necrosis

NE Necrotic edge

L Localised dermal reaction (restricted to a small area of the challenge site)

NP Necrotic patch

* Dryness and sloughing of the epidermis

# Thickening, dryness and sloughing of the epidermis

A Anterior site, exposed to the test material, 25 % v/v in Alembicol D

P Posterior site, exposed to the test material, 12.5 % v/v in Alembicol D

Second challenge

There were no dermal reactions seen in any of the test or control animals following the second challenge (all scores were 0), therefore all twenty test animals gave negative responses.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
In this study, the test material did not produce evidence of skin sensitization (delayed contact hypersensitivity) in any of the twenty test animals.
Executive summary:
This study was performed to assess the skin sensitization potential of phosphoric acid, mono- and di-(C8 -C10) ester, compds. with C12-14 amine using the guinea-pig maximisation test (OECD 406, Coleman, 1999). The test was designed according to Magnusson and Kligman Method. During the induction phase, 20 test animals were dosed by three pairs of 0.1 mL intradermal injections: 50 : 50 of Freund’s complete adjuvant with water, 0.25 % v/v of test article in vehicle (coconut oil: Alembicol D) and 0.25 % v/v in a 50 : 50 mixture of Freund’s complete adjuvant and Alembicol D. This was the highest concentration that caused irritation but did not adversely affect the animals. One week after the injections, the animals were treated topically with 0.4 mL of the test material, as supplied. The undiluted test material produced some irritation but did not adversely affect the animals. The patches were left in contact with skin for 48 hours. The twenty control animals (10 control and 10 naive control) were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application. Two weeks after the topical induction application, the test and first group of control animals were challenged topically using test material, 25 % and 12.5 % v/v in Alembicol D (25 % was the highest concentration not giving rise to irritating effects). Patches were applied occlusively to anterior and posterior sites of the flank of animals and were left in contact with the skin for 24 hours. A second challenge application was made one week later. In this case, the second group of ten control animals was used which were dosed with 1 and 0.5 % v/v. The challenge sites were evaluated 24 and 48 hours after removal of the patches. The site were also observed 72 hours after removal of the patches for the first challenge only.

After intradermal injections, slight to well-defined irritation was seen in test animals at sites receiving test material, 0.25 % v/v in Alembicol D and slight to well-defined irritation was observed in control animals receiving Alembicol D. Topical application during induction phase resulted in slight to well-defined erythema and slight erythema was seen in two control guinea-pigs. After the first challenge, well-defined to moderate dermal reactions were seen in the test and control animals which precluded meaningful assessment of sensitization. A second challenge was performed using lower concentrations of the test material. There were no dermal reactions seen in any of the test or control animals following the second challenge, therefore all twenty test animals gave negative responses. Based on this result, the test material did not produce evidence of skin sensitization (delayed contact hypersensitivity) and does not need to be classified and labelled as skin sensitizer.