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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not stated
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Study conducted prior to the loal lymph node assay becoming the assay of choice.
Specific details on test material used for the study:
- Name of test material (as cited in study report): Formi-LHS
- Substance type: salt
- Physical state: white powder
- Analytical purity: no data
- Storage condition of test material: at room temperature in the dark
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall Ltd; Burton on Trent
- Age at study initiation: approx. 6-11 weeks
- Weight at study initiation: body weight range of 428 to 773 g prior to dosing on Day 1
- Housing: in groups of up to five
- Diet: standard diet ad libitum
- Water: mains water ad libitum
- Acclimation period: 3 to 6 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 40-80
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12
Route:
other: intradermal and topical
Vehicle:
water
Concentration / amount:
1st application: Induction 0.5 % active substance intrdermal on Day 1
2nd application: Induction 15 % active substance topical on Day 8
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
3rd application: Challenge 5 or 10 % active substance occlusive epicutaneous
No. of animals per dose:
10 control animals; 20 test animals
Details on study design:
RANGE FINDING TESTS: yes


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: exposures on days 1 and 8
- Test groups: control and treated groups
- Control group: received water
- Frequency of applications: two single applications



B. CHALLENGE EXPOSURE
- No. of exposures: one
- Day(s) of challenge: day 22
- Exposure period: 24 hours
- Test groups: control and treated groups
- Control group: received water
- Evaluation (hr after challenge): 24 and 48 hours after termination of challenge
Challenge controls:
Yes
Positive control substance(s):
not required
Remarks:
hexyl cinnamic aldehyde (CAS number 101-86-0) and mercaptobenzothiazole (CAS number 149-30-4): regular positive testing (six monthly) in the laboratory
Positive control results:
Annex 1 to the report contains results of experiments conducted by the laboratory using a positive control substance (2-mercaptobenzothiazole). 6/9 and 6/10 animals gave positive reactions.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Control - vaseline
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
5%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
10%
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
control - vaseline
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Five animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
5%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
10%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
control - vaseline
No. with + reactions:
2
Total no. in group:
20
Clinical observations:
Three animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
5%
No. with + reactions:
4
Total no. in group:
20
Clinical observations:
Two animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10%
No. with + reactions:
8
Total no. in group:
20
Clinical observations:
Three animals showed desquamation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
control - vaseline
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Ten animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
5%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Five animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10%
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
Five animals showed desquamation
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
No. with + reactions:
6
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
No. with + reactions:
6
Total no. in group:
10
Remarks on result:
positive indication of skin sensitisation

Results of the main study:


No clinical observations of ill health or toxicity were noted. All animals gained weight over the course of the study.

Skin reactions after
intradermal induction: well defined erythema was noted at both anterior and posterior injection sites for both test and control animals. No erythema was noted at the middle injection sites in test animals receiving 1.0% Formi-LHS in purified water.

Skin reactions after topical application: slight erythema was apparent in test animals following application of 15% M/m
Formi-LHS in Vaseline. 

Skin reactions after challenge: slight erythema was noted at 24 h as tabulated below. All skin reactions had resolved at 48 h.
 

 

Table 1: Skin reactions after challenge - Controls

Animal No.

Score

24 hours

48 hours

A

P

C

A

P

C

1

0

0

0

0

0

0

2

0

0

0

0

0

0

3

0

0

0

0

0

0

4

1

0

0

0

0

0 Q

5

0

0

0

0

0

0 Q

6

0

0

0

0

0

0Q

7

0

0

0

1

0

0 Q

8

0

0

0

0

0

0

9

0

0

0

0

0

0

10

1

0

0

0

0

0 Q

 

Key:

A: anterior site exposed to 10% Formi-LHS in Vaseline

P: posterior site exposed to 5% Formi-LHS in Vaseline

C: control site exposed to Vaseline

0: no erythema

1: slight erythema

Q: desquamation

 

 

Table 2: Skin reactions after challenge – Test group

 

Animal No.

Score

Results

Positive [+]

Inconclusive [±)

Negative [-]

24 hours

48 hours

A

P

C

A

P

C

1

0

0

0

0

0

0

-

2

1

1

0

0

0

0 Q

-

3

1

1

1

0

0

0

-

4

1

0

0

1

0

0

-

5

0

0

0

0

0

0

-

6

0

0

0

0 Q

0 Q

0 Q

-

7

0

0

0

0

0

0

-

8

0

0

0

0

0

0

-

9

0

0

0

0

0

0

-

10

1

0

0

0 Q

0 Q

0 Q

-

11

1 Q

1 Q

0 Q

0 Q

0 Q

0 Q

-

12

0

0

0 Q

0

0

0 Q

-

13

1 Q

1 Q

1 Q

0

0

0 Q

-

14

1

0

0

0

0

0 Q

-

15

0

0

0

0 Q

0 Q

0 Q

-

16

0

0

0

0

0

0 Q

-

17

0

0

0

0

0

0

-

18

0

0

0

0

0

0

-

19

1 Q

0

0

0 Q

0 Q

0 Q

-

20

0

0

0

0

0

0

-

 

Key:

A: anterior site exposed to 10% Formi-LHS in Vaseline

P: posterior site exposed to 5% Formi-LHS in Vaseline

C: control site exposed to Vaseline

0: no erythema

1: slight erythema

Q: desquamation

 

 

Interpretation of results:
GHS criteria not met
Remarks:
Migrated information
Conclusions:
Potassium diformate lacks a skin sensitising potential. As it forms formic acid and formate anion in aqueous solutions, these are also considered to be negative.
Executive summary:

Potassium diformate (1:2) was not sensitizing in a Guinea pig maximization test (10 controls, 20 test animals) that was conducted according to OECD 406 and under GLP. The concentration of the test substance was 0.5 and 15% dissolved in purified water during induction and 10% at challenge; the test concentrations were selected following preliminary studies. No skin reactions were seen in the 20 test and 10 control animals at 24 or 48 hours after challenge. Potassium diformate, therefore, is not a skin sensitiser (Covance Laboratories, 1998).

 

The study is considered to be full valid and suitable for assessment. This does not only apply to potassium but also for formic acid and formate anion which are both formed by potassium formate in aqueous solution.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Read across can be made from Potassium diformate (1:2) which decomposes into potassium, formic acid, and formate anion in aqueous solution (cf. section 7.1.1).

Potassium diformate was not sensitizing in a Guinea pig maximization test (10 controls, 20 test animals) that was conducted according to OECD 406 and under GLP. The concentration of the test substance was 0.5 and 15% dissolved in purified water during induction and 10% at challenge; the test concentrations were selected following preliminary studies. No skin reactions were seen in the 20 test and 10 control animals at 24 or 48 hours after challenge. Potassium diformate, therefore, is not a skin sensitiser (Covance Laboratories, 1998

 

The study is considered to be full valid and suitable for assessment. This result can be extrapolated to potassium formate.



Migrated from Short description of key information:
Negative results from a related formate salt, potassium diformate, in the Guinea pig maximisation test suggest that formic acid and formate anion lack a skin sensitising potential. Potassium formate is therefore expected to be not a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Skin sensitisation:

No classification required. Criteria of regulations 67/548/EC and 1272/2008/EC are not met.