2-Pyridinesulfonamide, N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-(2,2,2-trifluoroethoxy)-, sodium salt (1:1)

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

19 May 1997 to 12 June 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was performed to GLP and in line with standardised guidelines OECD 406, EU Method B.6 and EPA OPP 81-6 with no deviations thought to impact on the reliability of the presented results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPP 81-6 (Skin Sensitisation)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: J-MAFF 59 NohSan No. 4200

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Currently no LLNA study is available for assessment. The GPMT test has been carried out as an animal test to predict human sensitisation for over a decade and is recommended by international test guidelines such as OECD.

Test material

Test material information

Constituent 1

Reference substance name:

sodium 4,6-dimethoxy-N-({[3-(2,2,2-trifluoroethoxy)pyridin-2-yl]sulfonyl}carbamoyl)pyrimidin-2-aminide

EC Number:

688-332-8

Cas Number:

199119-58-9

Molecular formula:

C14H13F3N5O6SNa

IUPAC Name:

sodium 4,6-dimethoxy-N-({[3-(2,2,2-trifluoroethoxy)pyridin-2-yl]sulfonyl}carbamoyl)pyrimidin-2-aminide

Test material form:

solid: particulate/powder

Details on test material:

- Physical state: solid (powder)
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: Himalayan Spotted (GOHI) GP 43

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: approximately 1 - 3 months
- Weight at study initiation: 324 - 449 g
- Housing: individually
- Diet: ad libitum
- Water: municipal water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2 °C
- Humidity (%): 55 ± 10 %
- Air changes (per hr): 13 - 14 air changes per hour
- Photoperiod: 12 hours light / 12 hours dark

IN-LIFE DATES: From 19 May 1997 to 12 June 1997

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

physiological saline

Induction 2

Concentration / amount:

1.0 % test material in physiological saline (intradermal induction)
1.0 % positive control in peanut oil (intradermal induction)

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Challenge 2

Concentration / amount:

1.0 % test material in physiological saline (intradermal induction)
1.0 % positive control in peanut oil (intradermal induction)

No. of animals per dose:

20 animals in each group (test material, vehicle control, positive control)

Details on study design:

RANGE FINDING TESTS:
- Intradermal application: 0.5, 1.0, 3.0 and 5.0 % of either test material in physiological saline or positive control in peanut oil
- A 5 cm wide area in the neck-shoulder region of one male and one female animals was shaved approximately 1 hour before treatment. A different pair of animals was used for each test group. Two pairs of intradermal injections (0.1 mL) of test material and one pair of injections for each concentration were administered, one of each pair on each side of the spine. The test sites were examined 24 and 48 hours after administration to determine the highest concentration to produce mild to moderate irritation without systemic toxicity.
- Epicutaneous application: 10, 20, 30 and 50 % test material in physiological saline or 10, 30 and 50% positive control in petroleum jelly.
- Two pairs of intradermal injections (0.1 mL) of a 1:1 mixture of test material/physiological saline were administered to 1 male and 1 female animal. Seven days later, the test material/vehicle mixture was applied, for each concentration, one on each flank. Test sites were examined 24 and 48 hours after administration to determine the highest concentration to cause mild to moderate irritation for the induction application and no irritation for the challenge application.

MAIN STUDY
INTRADERMAL INDUCTION EXPOSURE - DAY 0
- No. of exposures: 1 exposure
- Concentrations: 1.0 % test material in physiological saline or 1.0 % positive control in peanut oil
- Site: an area of approximately 5 cm x 5 cm on the back of the neck was shaved approximately 1 hour before treatment
- Treatment: three pairs of injections 0.1 mL in volume were given in the shaved area so that one of each pair was on each side of the midline)
- Vehicle control group injections:
(1) adjuvant/ physiological saline mixture, 1:1 v/v
(2) undiluted physiological saline vehicle
(3) physiological saline vehicle, 50% w/v with 1:1 adjuvant/physiological saline mixture
- Test material group injections:
(1) adjuvant/ physiological saline mixture, 1:1 v/v
(2) test material in physiological saline vehicle
(3) test material in 1:1 adjuvant/physiological saline mixture, 50 % w/v with physiological saline vehicle
- Positive control group injections:
(1) adjuvant/ physiological saline mixture, 1:1 v/v
(2) positive control in peanut oil vehicle
(3) positive control in 1:1 adjuvant/physiological saline mixture, 50 % w/v with peanut oil vehicle
- Frequency of applications: once on Day 0

EPIDERMAL APPLICATION INDUCTION EXPOSURE - DAY 8
- No. of exposures: 1 exposure
- Concentrations: 50 % test material in physiological saline or 50 % positive control in petroleum jelly
- Treatment: a filter paper patch was fully loaded (approximately 0.4 g) with the test material/ vehicle mixture, positive control/ vehicle mixture or physiological saline vehicle alone, and held in place with an occlusive dressing.
- Frequency of applications: once on Day 8
- Duration: 48 hours

EPIDERMAL APPLICATION CHALLENGE EXPOSURE - DAY 21
- No. of exposures: 1 exposure
- Vehicles: same as for epidermal application induction
- Day(s) of challenge: One challenege performed on day 21
- Concentrations: 10 % test material; 10 % positive control (highest non-irritant doses)
- Site: the flanks of all animals were shaved immediately prior to treatment
- Treatment: one chamber loaded with test material/ vehicle mixture (approximately 0.35 mL) was placed on one flank (test flank) and one chamber loaded with the respective vehicle alone was placed on the other flank (vehicle flank) of both test material and positive control group animals. Vehicle control group animals were treated the same as the test material group animals.
- Exposure period: The chambers were held in place with an occlusive dressing for 24 hours.
- Evaluation (hr after challenge): 24 and 48 hours

Positive control substance(s):

yes

Remarks:

2-mercaptobenzothiazole

Results and discussion

Positive control results:

Positive reactions were observed in 10 males and 9 females in the positive control group at both the 24 and 48 hour examinations on the test flanks, corresponding to a sensitization rate of 95 %. Scaling was seen in seven males and five females at the 48 hour observation. There were no positive reactions on the vehicle flanks.

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 % test material in vehicle

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: 10 % test material in vehicle. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 % test material in vehicle

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: 10 % test material in vehicle. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

100 % vehicle

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: negative control. Dose level: 100 % vehicle. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

100 % vehicle

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: negative control. Dose level: 100 % vehicle. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: none.

Results 5

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

10 % positive control in vehicle

No. with + reactions:

19

Total no. in group:

20

Clinical observations:

erythema and oedema

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: 10 % positive control in vehicle. No with. + reactions: 19.0. Total no. in groups: 20.0. Clinical observations: erythema and oedema.

Results 6

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

10 % positive control in vehicle

No. with + reactions:

19

Total no. in group:

20

Clinical observations:

erythema and oedema

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 10 % positive control in vehicle. No with. + reactions: 19.0. Total no. in groups: 20.0. Clinical observations: erythema and oedema.

Any other information on results incl. tables

There were no positive reactions at either the 24 or 48 hour readings among the test material group or vehicle control group animals on either the vehicle flank or the test flank. The sensitization rate of the test material was therefore 0 %.

There was no mortality during the study and no remarkable clinical observations. Bodyweights were not affected by treatment.

Table 3: Individual Skin Reactions in the Positive Control Group

Sex/ Animal	Vehicle flank				Test flank
	24 hours		48 hours		24 hours		48 hours
	erythema	oedema	erythema	oedema	erythema	oedema	erythema	oedema
M21	0	0	0	0	1	0	1	0
M22	0	0	0	0	2	0	1	0
M23	0	0	0	0	3	0	2	0
M24	0	0	0	0	2	0	1	0
M25	0	0	0	0	3	1	2	0
M26	0	0	0	0	1	1	2	1
M27	0	0	0	0	3	1	3	1
M28	0	0	0	0	3	1	2	1
M29	0	0	0	0	3	2	2	2
M30	0	0	0	0	1	0	2	0
F51	0	0	0	0	1	0	1	0
F52	0	0	0	0	3	1	2	1
F53	0	0	0	0	2	0	1	0
F54	0	0	0	0	3	2	2	2
F55	0	0	0	0	2	0	1	0
F56	0	0	0	0	1	0	1	0
F57	0	0	0	0	1	0	1	0
F58	0	0	0	0	0	0	0	0
F59	0	0	0	0	3	1	2	1
F60	0	0	0	0	3	2	2	1

 

Table 4: Individual Skin Reactions in the Test Material Test Group

Sex/ Animal	Vehicle flank				Test flank
	24 hours		48 hours		24 hours		48 hours
	erythema	oedema	erythema	oedema	erythema	oedema	erythema	oedema
M11	0	0	0	0	0	0	0	0
M12	0	0	0	0	0	0	0	0
M13	0	0	0	0	0	0	0	0
M14	0	0	0	0	0	0	0	0
M15	0	0	0	0	0	0	0	0
M16	0	0	0	0	0	0	0	0
M17	0	0	0	0	0	0	0	0
M18	0	0	0	0	0	0	0	0
M19	0	0	0	0	0	0	0	0
M20	0	0	0	0	0	0	0	0
F41	0	0	0	0	0	0	0	0
F42	0	0	0	0	0	0	0	0
F43	0	0	0	0	0	0	0	0
F44	0	0	0	0	0	0	0	0
F45	0	0	0	0	0	0	0	0
F46	0	0	0	0	0	0	0	0
F47	0	0	0	0	0	0	0	0
F48	0	0	0	0	0	0	0	0
F49	0	0	0	0	0	0	0	0
F50	0	0	0	0	0	0	0	0

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the study, the test material did not elicit a sensitisation reaction in guinea pigs. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.

Executive summary:

The skin sensitization potential of the test material was determined according to standardised guidelines OECD 4.6, EU Method B.6 and EPA OPP 81-6 following the Maximization procedure. Three groups of 20 guinea pigs (vehicle control, test material and positive control) were included. On day 0, the animals were given a set of intradermal injections, including 1.0 % test material in physiological saline for the test material group and 1.0 % positive control in peanut oil for the positive control group. The epidermal application was made on day 8; the vehicle control animals were treated with vehicle alone, the test material group with 50 % test material in physiological saline and the positive control group with 50 % positive control in petroleum jelly. The epidermal challenge application on day 21 consisted of a paired application of the vehicle alone and either 10 % test material in physiological saline or 10 % positive control in petroleum jelly. Skin reactions on both the vehicle and test flanks were scored 24 and 48 hours after completion of the challenge application, according to the Draize scale.

 

There were no positive skin responses among either the vehicle control or test group animals on either the vehicle flank of the test flank; the sensitization rate for the test material was therefore 0 %. Positive reactions were observed in 10 males and 9 females in the positive control group on the test flanks at both the 24 and 48 hour examinations, corresponding to a sensitization rate of 95 %. Scaling was seen in seven males and five females at the 48 hour observation. There was no mortality, and there were no remarkable clinical observations in any group. Bodyweights were not affected by treatment.

 

According to the Magnusson and Kligman Maximization grading, the test material is classified as a weak sensitizer, the lowest possible grade. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.