Potassium 3-sulphonatopropyl acrylate

Endpoint summary

Description of key information

Guinea pig maximisation test (OECD 406): skin sensitising

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:

03 Aug - 08 Sep 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The study was conducted prior to the current requirement in Regulation (EC) 1907/2006 to perform an LLNA study (OECD 429) as the preferred in vivo skin sensitisation study.

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: approximately 8-12 weeks
- Weight at study initiation: 300-450 g
- Housing: animals were housed singly or in pairs in solid-floor polypropylene cages furnished with woodflakes
- Diet: Guinea Pig FD1 Diet (Special Diets Services Limited, Witham, Essex, UK), ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-23
- Humidity (%): 30-70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal

Vehicle:

water

Concentration / amount:

0.5% (w/w)

Day(s)/duration:

Single injection

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

75% (w/w)

Day(s)/duration:

48 h

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

50 and 75% (w/w)

Day(s)/duration:

24 h

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 in test group, 5 in control group

Details on study design:

RANGE FINDING TESTS:
In the range-finding study, intradermal injections were made on the shaved shoulder of 4 guinea pigs using concentrations of 0.1, 0.5, 1 and 5% w/w in distilled water. The degree of erythema was assessed 24, 48 and 72 hours, and 7 days after the injection. The highest concentration causing mild to moderate skin irritation was selected for the intradermal induction stage of the main study. Two guinea pigs (intradermally injected with Freund's complete adjuvant 9 days earlier) were each treated with 10, 25, 50 and 75% (w/w in distilled water) solutions of the test substance. The solution was applied to clipped flanks and covered with an occlusive dressing for 48 hours. The degree of erythema and edema was assessed 1, 24 and 48 hours after exposure ended. The highest concentration causing mild to moderate skin irritation was selected for the topical induction stage of the main study. Two guinea pigs were each treated with 10, 25, 50 and 75% (w/w in distilled water) solutions of the test substance. The solution was applied to clipped flanks and covered with an occlusive dressing for 24 hours. The degree of erythema and edema was assessed 1, 24 and 48 hours after exposure ended. The highest non-irritant concentration and one lower concentration were selected for the challenge stage of the main study.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2, intradermal and epicutaneous
- Exposure period: single injection (intradermal, left and right side) and 48 hours (epicutaneous)
- Test groups:

Intradermal (3 pairs of injections, 0.1 mL):
Injection 1: a 1:1 mixture (v/v) FCA/water
Injection 2: 0.5% w/w test substance in distilled water
Injection 3: 0.5% w/w test substance in a 1:1 mixture (v/v) FCA/water
24 and 48 h after intradermal injection, the degree of erythema and edema was evaluated.

Epicutaneous:
75% w/w test substance in distilled water
On day 7 the animals were treated with a topical application of SPA. The occlusive dressing was kept in place for 48 h. The degree of erythema and edema was evaluated 1 and 24 h after removing the patch.

- Control group:
Intradermal (3 pairs of injections):
Injection 1: a 1:1 mixture (v/v) FCA/water
Injection 2: distilled water
Injection 3: distilled water in a 1:1 mixture (v/v) FCA/water
Epicutaneous: distilled water

- Site: approximately 40 mm x 60 mm area on the shoulder region
- Frequency of applications: once (intradermal and epicutaneous)
- Duration: day 0 (intradermal), day 7-9 (epicutaneous)
- Concentrations: 0.5% (intradermal), 75% (epicutaneous)

B. CHALLENGE EXPOSURE
- No. of exposures: one, topical
- Day(s) of challenge: 21
- Exposure period: 24 hours
- Test groups: test substance in distilled water
- Control group: test substance distilled water
- Site: approximately 50 mm x 70 mm, on both flanks of the animals
- Concentrations: 75% SPA on the right flank and 50% SPA on the left flank
- Evaluation (hr after challenge): 24 and 48 hours after exposure ended

OTHER: remaining test material was removed from the test site after epicutaneous exposure lasting 24 h

Positive control substance(s):

yes

Remarks:

historical data using 2-mercaptobenzothiazole and alpha-hexylcinnamaldehyde in arachis oil as positive controls was included

Positive control results:

Historical data on two positive control substances (2-mercapobenzothiazole and alpha-hexylcinnamaldehyde) show that they induced positive reactions in control animals, thus meeting the reliability criteria for the GPMT. In four independent studies performed in 1999 and 2000, 2-mercapobenzothiazole induced sensitisation in 90-100% of the animals. A 5% solution was used for intradermal induction, 50% solution for topical induction, and 50% and 25% for topical challenge. In two independent studies performed in 2000 and 2001, alpha-hexylcinnamaldehyde induced sensitisation in 40% and 50% of the animals, respectively. A 5% solution was used for intradermal induction, 100% solution for topical induction, and 100% and 75% for topical challenge. See results table under 'Attached background material' (Positive control historical data).

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.5% (intradermal induction); 50% (epicutaneous challenge)

No. with + reactions:

9

Total no. in group:

9

Remarks on result:

positive indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.5% (intradermal induction); 75% (epicutaneous challenge)

No. with + reactions:

9

Total no. in group:

9

Remarks on result:

positive indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0% (intradermal induction); 50% (epicutaneous challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0% (intradermal induction); 75% (epicutaneous challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.5% (intradermal induction); 50% (epicutaneous challenge)

No. with + reactions:

9

Total no. in group:

9

Remarks on result:

positive indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.5% (intradermal induction); 75% (epicutaneous challenge)

No. with + reactions:

9

Total no. in group:

9

Remarks on result:

positive indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0% (intradermal induction); 50% (epicutaneous challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0% (intradermal induction); 75% (epicutaneous challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Group:

positive control

Dose level:

5% (intradermal induction); 25 and 50% (epicutaneous challenge)

No. with + reactions:

9

Total no. in group:

9

Remarks on result:

positive indication of skin sensitisation

Remarks:

Summary of the most recent positive control experiment for 2-Mercaptobenzothiazole in male guinea pigs

Group:

positive control

Dose level:

5% (intradermal induction); 75 and 100% (epicutaneous challenge)

No. with + reactions:

4

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Remarks:

Summary of the most recent positive control experiment for α-Hexylcinnamaldehyde in male guinea pigs

There were no treatment-related effects on body weight. One guinea pig in the test group was prematurely sacrificed on day 22, due to respiratory problems, weight loss and hypothermia. These effects are not considered to be treatment-related.

Slight to moderate erythema was noted at the injection sites of exposed and control animals after intradermal induction (see table 1). Following the topical induction, slight to moderate erythema and slight edema was noted at the test site in treated animals. Bleeding from the injection sites was noted in 3 treated and 2 control group animals.

The topical challenge caused positive skin responses (slight to moderate and confluent erythema with or without very slight edema) in 9/9 animals at the skin site with 75% test substance at the 24 and 48 hour time points. At the site with 50% test substance, 9/9 animals had a positive skin response (slight to moderate and confluent erythema).

Table 1: Intradermal induction, individual skin reactions

^Group	^Animal number	^Grade of erythema at observation site
		^24 hours		^48 hours
		^Left side	^Right side	^Left side	^Right side
^Test	^1	^1	^1	^0	^0
	^2	^1	^1	^0	^0
	^3	^2	^2	^1	^1
	^4	^1	^2	^1	^1
	^5	^1	^1	^1	^0
	^6	^1	^1	^0	^0
	^7	^1	^1	^1	^0
	^8	^1	^1	^0	^0
	^9	^1	^1	^1	^1
	^10	^1	^1	^1	^1
^Control	^11	^1	^1	^0	^0
	^12	^1	^1	^0	^0
	^13	^1	^1	^0	^0
	^14	^1	^1	^0	^0
	^15	^1	^1	^0	^0

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: Skin sens 1A, H317

The skin sensitisation classification category 1 for sulfopropyl acrylate (SPA) is based on the challenge results that all test animals (9/9) gave a positive response. The classification was further specified to be 1A, based on the intradermal induction concentration. The concentration tested at intradermal induction was 0.5% SPA. As the percentage of animals with positive reaction at challenge is 100% and thus above the 60% cut-off point for classification as skin sensitiser 1A, the classification criteria are met. Therefore, classification for skin sens 1A is justified.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitising potential of sulfopropyl arcylate (SPA) was evaluated in a Guinea Pig Maximisation Test (GMPT) performed according to OECD 406 (Driscoll, 2001). For induction, the test animals were treated once with 0.5% SPA including the adjuvants by three intradermal injections on each side of the mid-line followed by a 48-hour topical application of 75% SPA at the same skin sites. For induction of controls, the test substance was omitted from the intradermal injections as well as the topical application. On Day 21, all animals were challenged with 75% SPA (right flank) and 50% SPA (left flank) for 24 hours.

24 hours after the intradermal induction, all animals in the test group (10/10) and all controls (5/5) showed discrete or patchy to moderate and confluent erythrema at all injection sites. The reactions persisted after 48 hours on the right (6/10) and on the left side (4/10) of the test animals whereas the reaction cleared in the controls. One and 24 hours after topical induction discrete or patchy to moderate and confluent erythema and very slight oedema were noted at the topical induction sites of the test animals. No signs of erythema or oedema were observed for controls.

At challenge, positive skin reactions (discrete or patchy to moderate and confluent erythema, with or without very slight oedema) were seen for 9/9 test animals at the 24 h and 48 h reading time point for both test concentrations. No skin effects were observed in the animals of the control group after challenge.

There were not treatment-related effects on body weight. One guinea pig in the test group was prematurely sacrificed on Day 22, due to respiratory problems, weight loss and hypothermia, but these effects were not considered to be treatment-related.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Study not required according to Annex VII-X of Regulation (EC) No 1907/2006

Justification for classification or non-classification

The available data on skin sensitisation of the test substance meet the criteria for classification as skin sens 1A (H317) according to Regulation (EC) 1272/2008.

The skin sensitisation classification category 1 for sulfopropyl acrylate (SPA) is based on the challenge results that all test animals (9/9) gave a positive response. The classification was further specified to be 1A, based on the intradermal induction concentration. The concentration tested at intradermal induction was 0.5% SPA. As the percentage of animals with positive reaction at challenge is 100% and thus above the 60% cut-off point for classification as skin sensitiser 1A, the classification criteria are met. Therefore, classification for skin sens 1A is justified.