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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Please refer also to Read Across Statement attached in Section 13

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In this read-across approach data choline chloride are used to fill data gaps for choline hydroxide, in accordance with Regulation No 1907/2006 (REACH), Annex XI. The basis for this read-across approach is the “Read-Across Assessment Framework” (RAAF) (ECHA 2017). The read-across hypothesis for the analogue approach is that choline hydroxide and choline chloride exhibit a similar (eco)toxicological profile. This is due to the fact that both choline salts as quaternary alkylammonium salts dissociate readily into the respective ions when getting into contact with water and the choline cation is what is left to be considered (US EPA, 2010). Thus, the different choline salts are used to for hazard assessment. According to the RAAF this approach is covered by scenario 1: “(Bio)transformation to common compound(s)”.
“This scenario covers the analogue approach for which the read-across hypothesis is based on (bio) transformation to common compound(s). For the REACH information requirement under consideration, the property investigated in a study conducted with one source substance is used to predict the properties that would be observed in a study with the target substance if it were to be conducted. Similar properties or absence of effect are predicted. The predicted property may be similar or based on a worst-case approach.” (ECHA 2017).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source chemical:
2-hydroxy-N,N,N-trimethylethanaminium chloride
Molecular formula: C5H14ClNO
SMILES: [Cl-].C[N+](C)(C)CCO
CAS: 67-48-1
Purity: not specified

Target chemical:
Choline hydroxide
Molecular formula: C5H15NO2
SMILES: [OH-].C[N+](C)(C)CCO
CAS: 123-41-1
Purity: 96 %

3. ANALOGUE APPROACH JUSTIFICATION
Upon contact with water, choline hydroxide is expected to dissociate into the cationic form (choline) and the anionic form (hydroxide ions); the hydroxy moiety dissociates and essentially ceases to exist upon mixing with water in preparation for application and in the body. The latter will be even skipped because both choline hydroxide and choline chloride are only distributed as aqueous solution, i.a. due to their hygroscopic properties. The choline cation is what is left to be considered (US EPA, 2010). Due to the structural similarities, i.e. the identical organic cation, which contains a positively charged nitrogen, and small, negatively charged inorganic anion (for choline base: Hydroxide), this is a reasonable and scientifically expectable conclusion, which allow one to draw the generalized conclusion, that Choline salts in general dissociate readily in water into the corresponding positively charged quaternary hydroxyl alkylammonium ion and the negatively charged inorganic anion (OECD SIDS, 2004). The choline cation therefore, is the moiety of interest. Based on the fact that in the environment and in biological fluids the same compounds are formed from the source and the target substances, the same (eco)toxicological profile of choline hydroxide and choline chloride is expected. Therefore, the read-across approach is justified. Thus, the available studies for the source substance choline chloride were used to fill data gaps for choline hydroxide for several environmental and toxicological endpoints.
Cross-reference
Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
other: Experimental result on a formulation of Choline chloride (CC) with the structural analogue Chlorocholine chloride (CCC).
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well-documented Guideline study according GLP, but performed on formulation of Choline chloride with structural analogue (Chlorocholine chloride).
Reason / purpose for cross-reference:
reference to other study
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
adopted 1992-07-17
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
Directive 96/54/EEC
Deviations:
no
GLP compliance:
yes
Remarks:
including compliance statement
Type of study:
guinea pig maximisation test
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: approx. 8 - 12 weeks
- Weight at study initiation: 312 - 393 g
- Housing: singly or in pairs in solid-floor polypropylene cages furnished with woodflakes
- Diet (e.g. ad libitum): Guinea Pig FD1 Diet, Special Diets Services Limited, Witham, Essex, UK; ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 22
- Humidity (%): 48 - 56
- Air changes (per hr): approx. 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Other: each animal was selected at random and given a number unique within the study which was written on a small area of clipped rump using a black indelible marker-pen.
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
5 % w/v solution in distilled water (Intradermal induction)
undiluted as supplied (Topical induction)
undiluted as supplied and 75 % v/v in water (Topical induction)
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
5 % w/v solution in distilled water (Intradermal induction)
undiluted as supplied (Topical induction)
undiluted as supplied and 75 % v/v in water (Topical induction)
No. of animals per dose:
10 (test group)
5 (control group)
Details on study design:
RANGE FINDING TESTS:
- Single intradermal exposure with 0.1 mL of either 1 %, 5 %, 10 % or 25 % w/v of the test item in distilled water, sighting test, for intradermal induction
- Two guinea pigs, intradermally injected with Freund's Complete Adjuvant fifteen days earlier, were topically (occlusive) exposed to 100 %, 75 %, 50 % and 25 % v/v of the test item in distilled water, for topical induction
- 100 %, 75 %, 50 % and 25 % v/v of the test item in distilled water, 14 d after induction with Freund´s Complete Adjuvant analogue to control animals in the main study, for topical challenge

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1 intradermal (row of three injections, see additional information), 1 topical 7 days later
- Exposure period: 48 h for topical induction
- Test groups:
Intradermal Induction: row of three injections, (1) Freund´s Complete Adjuvans (FCA) and H2O dest. 1:1, (2) 5 % w/v solution of the test material in distilled water, (3) 5 % w/v solution of the test material in distilled water and FCA plus H2O dest. 1:1
Topical induction: undiluted test material
- Control group:
Intradermal Induction: row of three injections, (1) Freund´s Complete Adjuvans (FCA) and H2O dest. 1:1, (2) distilled water, (3) 50 % distilled water and FCA plus H2O dest. 1:1
Topical induction: bare filter paper
- Site: shoulder
- Frequency of applications: Day 1 and 7
- Duration: Total 9 d
- Concentrations: 5 % w/v in water (intradermal), undiluted (topical)

B. CHALLENGE EXPOSURE
- No. of exposures:
- Day(s) of challenge: Day 21
- Exposure period: 48h
- Test groups: undiluted as supplied and 75 % v/v of test item in distilled water
- Control group: undiluted as supplied and 75 % v/v of test item in distilled water
- Site: right (100 % test item) and left (75 % v/v) shorn flank
- Concentrations: undiluted and 75 % v/v
- Evaluation (hr after challenge): 24h and 48 h
Challenge controls:
5 animals, undiluted test item and 75 % v/v of test item in distilled water
Positive control substance(s):
yes
Remarks:
historical control data from Neomycin Sulphate, 2-Mercaptobenzothiazole, 2,4-Dinitrochlorobenzene
Positive control results:
See attached background material "Driscoll_PositiveControlData" which demonstrates clearly that the laboratory has the capability to identify positive dermal sensitizers.
The incidences of sensitization of the test animals were 60 % (Neomycin Sulphate), 70 - 90 % (2-Mercaptobenzothiazole) and 100 % (2,4-Dinitrochlorobenzene).
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
other: challenge control
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: challenge control. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
other: challenge control
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: challenge control. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
other: challenge control
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: other: challenge control. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
other: challenge control
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: challenge control. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..

 

TABLE 1

Challenge concentrations: Undiluted as supplied and 75 % v/v

Vehicle: Distilled water

Animal Number

Skin Reactions (Hours After Removal of Dressing)

24 Hours

48 Hours

100 %

75 %

100 %

75 %

Er

Oe

Other

Er

Oe

Other

Er

Oe

Other

Er

Oe

Other

Individual skin reactions in test animals after challenge

1

0

0

-

0

0

-

0

0

-

0

0

-

2

0

0

-

0

0

-

0

0

-

0

0

-

3

0

0

-

0

0

-

0

0

-

0

0

-

4

0

0

-

0

0

-

0

0

-

0

0

-

5

0

0

-

0

0

-

0

0

-

0

0

-

6

0

0

-

0

0

-

0

0

-

0

0

-

7

0

0

-

0

0

-

0

0

-

0

0

-

8

0

0

-

0

0

-

0

0

-

0

0

-

9

0

0

-

0

0

-

0

0

-

0

0

-

10

0

0

-

0

0

-

0

0

-

0

0

-

Individual skin reactions in control animals after challenge

11

0

0

-

0

0

-

0

0

-

0

0

-

12

0

0

-

0

0

-

0

0

-

0

0

-

13

0

0

-

0

0

-

0

0

-

0

0

-

14

0

0

-

0

0

-

0

0

-

0

0

-

15

0

0

-

0

0

-

0

0

-

0

0

-

Interpretation of results:
GHS criteria not met
Conclusions:
The present study is a well-documented GLP study according OECD guideline 406 (Guinea pig maximisation test) with the restriction, that it was conducted not only on Choline chloride (CC) but on a formulation with CC (320 g/L) and chlorocholine chloride (CCC, 460 g/L), whereas the latter was shown not to be a sensitizer in the study by Suresh. So in general, the study was classified as Klimisch 2 and hence, the results can be safely used to assess the sensitising potential of Choline chloride, and hence, choline hydroxide, due to the immediate dissociation of both salts and the irrelevance of the inorganic anions. The test item contains two relevant parts choline chloride, i.e. 41 % of the solid ingredients, and the solvent (water) is not a known sensitizer. So since neither water nor CCC, which may also serve as a read-across substance, was shown to be a dermal sensitizer, it can be concluded that every possible positive result obtained from the formulation must be attributed to choline chloride. Since no animal of the test group at no timepoint of observation showed any skin reaction during the challenge phase, and the dose of the test item was properly determined by preliminary sighting tests as the demanded highest non-irritating dose, it can safely be concluded that the test item did not exhibit any sensitizing properties and consequently, that choline hydroxide is non-sensitizing, too. Hence, choline chloride does not need to be classified as skin-sensitizer according Regulation 1272/2008/EC. However, the corrosive properties of choline base must be kept in mind for classification.
Executive summary:

In a dermal sensitization study according GLP and OECD guideline 406 with a formulation of the read-across substances choline chloride (CC) and chlorocholine chloride (CCC) (320 g/L CC, 460 g/L CCC) in water, 8 - 12 weeks old male albino Dunkin Hartley guinea pigs (10 animals/ test were tested in the Guinea pig maximization test (GPMT according to Magnus and Kligmann)). Induction was performed once intradermal (Day 1) and once topical (Day 7, occlusive), topical challenge was on Day 21 (occlusive). Historical data from Neomycin Sulphate, 2-Mercaptobenzothiazole and 2,4-Dinitrochlorobenzene served as positive controls and induced the anticipated effect.

No skin reactions were observed, neither in the test nor control group, and body weight gain of the test group was similar to control. Since no sensitizing effects were noted in none of the test animals in this study, the formulation of CC and CCC, and consequently also pure Choline chloride and choline hydroxide, are not dermal sensitizers, and do therefore not need to be classified as sensitizing according Regulation 1272/2008/EC.

Data source

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
Choline hydroxide
EC Number:
204-625-1
EC Name:
Choline hydroxide
Cas Number:
123-41-1
Molecular formula:
C5H14NO.HO
IUPAC Name:
choline hydroxide

Results and discussion

Positive control results:
See attached background material "Driscoll_PositiveControlData" which demonstrates clearly that the laboratory has the capability to identify positive dermal sensitizers.
The incidences of sensitization of the test animals were 60 % (Neomycin Sulphate), 70 - 90 % (2-Mercaptobenzothiazole) and 100 % (2,4-Dinitrochlorobenzene).

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin reactions or differences in body weight gain compared to control were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: No skin reactions or differences in body weight gain compared to control were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
other: challenge control
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: other: challenge control. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
other: challenge control
Dose level:
100 % of the test item as supplied
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: challenge control. Dose level: 100 % of the test item as supplied. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
1st reading
Hours after challenge:
24
Group:
other: challenge control
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: other: challenge control. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..
Reading:
2nd reading
Hours after challenge:
48
Group:
other: challenge control
Dose level:
75 % v/v of the test item in distilled water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
No skin reactions were noted.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: other: challenge control. Dose level: 75 % v/v of the test item in distilled water. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: No skin reactions were noted..

Any other information on results incl. tables

 

TABLE 1

Challenge concentrations: Undiluted as supplied and 75 % v/v

Vehicle: Distilled water

Animal Number

Skin Reactions (Hours After Removal of Dressing)

24 Hours

48 Hours

100 %

75 %

100 %

75 %

Er

Oe

Other

Er

Oe

Other

Er

Oe

Other

Er

Oe

Other

Individual skin reactions in test animals after challenge

1

0

0

-

0

0

-

0

0

-

0

0

-

2

0

0

-

0

0

-

0

0

-

0

0

-

3

0

0

-

0

0

-

0

0

-

0

0

-

4

0

0

-

0

0

-

0

0

-

0

0

-

5

0

0

-

0

0

-

0

0

-

0

0

-

6

0

0

-

0

0

-

0

0

-

0

0

-

7

0

0

-

0

0

-

0

0

-

0

0

-

8

0

0

-

0

0

-

0

0

-

0

0

-

9

0

0

-

0

0

-

0

0

-

0

0

-

10

0

0

-

0

0

-

0

0

-

0

0

-

Individual skin reactions in control animals after challenge

11

0

0

-

0

0

-

0

0

-

0

0

-

12

0

0

-

0

0

-

0

0

-

0

0

-

13

0

0

-

0

0

-

0

0

-

0

0

-

14

0

0

-

0

0

-

0

0

-

0

0

-

15

0

0

-

0

0

-

0

0

-

0

0

-

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The present study is a well-documented GLP study according OECD guideline 406 (Guinea pig maximisation test) with the restriction, that it was conducted not only on Choline chloride (CC) but on a formulation with CC (320 g/L) and chlorocholine chloride (CCC, 460 g/L), whereas the latter was shown not to be a sensitizer in the study by Suresh. So in general, the study was classified as Klimisch 2 and hence, the results can be safely used to assess the sensitising potential of Choline chloride, and hence, choline hydroxide, due to the immediate dissociation of both salts and the irrelevance of the inorganic anions. The test item contains two relevant parts choline chloride, i.e. 41 % of the solid ingredients, and the solvent (water) is not a known sensitizer. So since neither water nor CCC, which may also serve as a read-across substance, was shown to be a dermal sensitizer, it can be concluded that every possible positive result obtained from the formulation must be attributed to choline chloride. Since no animal of the test group at no timepoint of observation showed any skin reaction during the challenge phase, and the dose of the test item was properly determined by preliminary sighting tests as the demanded highest non-irritating dose, it can safely be concluded that the test item did not exhibit any sensitizing properties and consequently, that choline hydroxide is non-sensitizing, too. Hence, choline chloride does not need to be classified as skin-sensitizer according Regulation 1272/2008/EC. However, the corrosive properties of choline base must be kept in mind for classification.
Executive summary:

In a dermal sensitization study according GLP and OECD guideline 406 with a formulation of the read-across substances choline chloride (CC) and chlorocholine chloride (CCC) (320 g/L CC, 460 g/L CCC) in water, 8 - 12 weeks old male albino Dunkin Hartley guinea pigs (10 animals/ test were tested in the Guinea pig maximization test (GPMT according to Magnus and Kligmann)). Induction was performed once intradermal (Day 1) and once topical (Day 7, occlusive), topical challenge was on Day 21 (occlusive). Historical data from Neomycin Sulphate, 2-Mercaptobenzothiazole and 2,4-Dinitrochlorobenzene served as positive controls and induced the anticipated effect.

No skin reactions were observed, neither in the test nor control group, and body weight gain of the test group was similar to control. Since no sensitizing effects were noted in none of the test animals in this study, the formulation of CC and CCC, and consequently also pure Choline chloride and choline hydroxide, are not dermal sensitizers, and do therefore not need to be classified as sensitizing according Regulation 1272/2008/EC.