Potassium carbamoylcarbamate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to GLP/OECD guildeline without deficiency.

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source:Nulliparous, non-pregnant female CBA/CaCrl strain mice obtained from Charles River (UK) Ltd, Margate.
- Age at study initiation: 8 to 10 weeks old.
- Weight at study initiation: 15 to 20 g
- Housing:Group housed during acclimatisation and individually housed from Day –1 in cages.
- Diet (e.g. ad libitum):SQC(E) Rat and Mouse Maintenance Diet No 1, from Special Diets Services Ltd, Witham, UK was freely available to the animals at all times.
- Water (e.g. ad libitum):Mains water was provided, ad libitum, via cage-mounted water bottles.
- Acclimation period: 8 to 15 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):20 to 24 degrees C
- Humidity (%):45 to 65%
- Air changes (per hr):15 to 20
- Photoperiod (hrs dark / hrs light):12/12

IN-LIFE DATES: From 17 January 2012 To 31 January 2012

Route:

epicutaneous, open

Vehicle:

DMSO

Concentration / amount:

0, 10%, 25%, 50% w/v

Route:

other: intravenous, tail vein

Vehicle:

DMSO

Concentration / amount:

0, 10%, 25%, 50% w/v

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS: A preliminary screening test was performed with one mouse. The mouse was treated by daily application of 25 µL of the test
article at the maximum suitable concentration (50% w/v in DMSO) to the dorsal surface of each ear for three consecutive days (Days 1, 2 and 3). The mouse was observed daily for five days from the initiation of treatment. Any signs of toxicity or irritation during this period were recorded.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures:3
- Exposure period: 24 hours
- Site:Outer aspect of both auditory pinnae.
- Frequency of applications:once daily
- Duration:Once daily on Days 1, 2 and 3.
- Concentrations: 0.25 mL/pinna

B. CHALLENGE EXPOSURE
- No. of exposures:1
- Day(s) of challenge:1
- Site: Tail vein injection.
- Concentrations:0.25 mL phosphate buffered saline incorporating 20 μCi of 3HTdR.
- Evaluation (hr after challenge):5 hours

Positive control substance(s):

yes

Remarks:

α-hexylcinnamaldehyde formulated at a concentration of 25% in acetone / olive oil (4:1 v/v)

Vehicle:

dimethyl sulphoxide

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility:Soluble at the maximum suitable concentration(50% w/v in DMSO).
- Irritation:no
- Lymph node proliferation response:no

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response:Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation counts obtained from the test groups relative to the corresponding mean scintillation count obtained from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

TREATMENT PREPARATION AND ADMINISTRATION:
Each mouse was manually restrained with both auditory pinnae left free. The outer aspect of both pinnae of each mouse was treated by direct
application of the appropriate test or control formulation (0.025 mL/pinna) dispensed from an automatic micro pipette.
The five groups of five female mice were subjected to application of the vehicle control, positive control or one of the test formulations to the outer
aspect of the auditory pinnae, once daily on Days 1, 2 and 3.
On Day 6 the mice were placed in a warming cabinet in order to dilate the peripheral blood vasculature and thus facilitate intravenous dosing. Each mouse was transferred to a cylindrical restrainer. A plastic syringe and fine gauge hypodermic needle were used to administer 0.25 mL phosphate
buffered saline incorporating 20 μCi of 3HTdR into a tail vein of each mouse by slow bolus injection. After this treatment, the mice were returned to
their cages.
Approximately five hours after intravenous injection of the 3HTdR, all mice were sacrificed by exposure to a rising concentration of carbon dioxide.
The interval between sacrifice and the recovery of the auricular lymph nodes was no more than fifteen minutes.
The auricular lymph nodes were located and removed using curved end forceps. Any connective tissue was removed from the capsule of the nodes. The auricular lymph nodes of each mouse were then processed for scintillation count.

Positive control results:

The positive control article produced a Stimulation Index of 4.49.

Parameter:

SI

Remarks on result:

other: Vehicle: NA 10%: 0.55 25%: 1.22 50%: 0.67 Positive control: 4.49 10%: 330± 138.7 25%: 730 ± 565.8 50%: 401 ± 126.5 Positive control: 2693 ± 1860.1

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Vehicle: 599± 196.1 10%: 330± 138.7 25%: 730 ± 565.8 50%: 401 ± 126.5 Positive control: 2693 ± 1860.1

Individual DPMs and Stimulation Index (SI)

Concentration (%w/v) in DMSO	Group number	Animal number	DPM/ animal	Mean DPM/animal (Standard Deviation)	Stimulation Index (SI)^a
Vehicle	1	49	506	599 (± 196.1)	NA
		50	509
		51	941
		52	458
		53	583
10	2	54	146	330 (± 138.7)	0.55
		55	313
		56	421
		57	265
		58	504
25	3	59	711	730 (± 565.8)	1.22
		60	790
		61	186
		62	328
		63	1635
50	4	64	389	401 (± 126.5)	0.67
		65	285
		66	521
		67	540
		68	272
Positive control	5	69	1308	2693 (± 1860.1)	4.49
		70	1715
		71	1619
		72	3013
		73	5809

Key

DMSO    dimethyl sulphoxide

NA = Not applicable

^a= Stimulation Index of 3.0 or greater indicates a positive result

 

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information

Conclusions:

The Local Lymph Node Assay demonstrated that Potassium Allophonate does not have the potential to cause skin sensitisation.
The test article did not meet the criteria for classification as a sensitiser according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a skin sensitisation study conducted according to OECD Testing Guideline 429 with mice, potassium allophonate did not result in any skin sensitisation effects. Therefore, the current data indicate that potassium allophonate is not a skin sensitiser.

Migrated from Short description of key information:
Potassium allophonate was evaluated for skin sensitisation in a local lymph node assay (LLNA) in mice (OECD Testing Guideline 429). None of the test animals produced a skin sensitisation stimulation index over 3 in this study. Therefore, the current data indicate that potassium allophonate is not a skin sensitiser.

Justification for selection of skin sensitisation endpoint:
Study performed under Good Laboratory Practices (GLP)/Organisation for Economic Co-operation and Development (OECD) testing guidelines.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Migrated from Short description of key information:
Although no study data specifically evaluating potential respiratory sensitisation effects are available for potassium allophonate, based on the lack of human case reports indicating potassium allophonate is a respiratory sensitiser, as well as negative responses observed in both the skin sensitisation and skin irritation animal studies, potassium allophonate is not likely to be a respiratory sensitiser.

Justification for classification or non-classification

Potassium allophonate was found to be non-sensitising in a skin sensitisation study conducted in accordance with OECD Testing Guideline 429. Therefore, no classification is warranted for the skin sensitisation endpoint. No respiratory sensitisation study is available for potassium allophonate. Therefore, classification cannot be made due to lack of data.