Bromoacetic acid

Endpoint summary

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:

June 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD, EPA, etc)

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

and EU B.6, skin sensitization

Deviations:

yes

Remarks:

Two animals showed a body weight Slightly higher than 400 g at the start of the study. One animal had its bandages removed after 48 hours instead of 24 hours during the challenge treatment.

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

other: SPF-bred albino guinea pigs (Crl: (HA)BR)

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga GmbH, Germany
- Age at study initiation: young adult
- Weight at study initiation: males 316-410 g; females 329-380 g
- Housing: individually in suspended, stainless steel cages, fitted with wire mesh floor and front
- Diet (e.g. ad libitum): pelleted, natural ingredient diet for guinea pigs (Hope Farms, Woerden, The Netherlands), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+/- 3°C
- Humidity (%): 45%-65%
- Air changes (per hr): ca 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark cycle

Route:

intradermal

Vehicle:

other: demineralised water

Concentration / amount:

- For induction intradermal: 0.03% Bromoacetic acid in demineralised water or 0.03% Bromoacetic acid in demineralised water and FCA (Freund’s Complete Adjuvant; 1:1)
- Topical: 5% Bromoacetic acid in demineralised water
- For challenge: 1% Bromoacetic acid in demineralised water

Route:

intradermal

Vehicle:

other: demineralised water

Concentration / amount:

- For induction intradermal: 0.03% Bromoacetic acid in demineralised water or 0.03% Bromoacetic acid in demineralised water and FCA (Freund’s Complete Adjuvant; 1:1)
- Topical: 5% Bromoacetic acid in demineralised water
- For challenge: 1% Bromoacetic acid in demineralised water

No. of animals per dose:

10

Details on study design:

RANGE FINDING TESTS: yes
The intradermal toxicity and irritation response upon intradermal injection of various concentrations were examined in 3 guinea pigs.
- Amounts of 0.1 ml of a 1%, a 0.3%, and a 0.1% dilution of the test substance in demi-water were applied by intradermal injection.
- The irritation response to topical treatment of a 10%, a 3% and a 1% dilution of the test substance in demi-water were examined after an application of 24 hours.

MAIN STUDY
- Test groups: 10 animals per group (10 males and 10 females)
- Control group: yes (5 males and 5 females)
Induction schedule:

* day 0 – 1. induction
* day 7 – 2. induction
* day 21 – challenge
* day 22 – 1. scoring
* day 23 – 1. scoring

A. INDUCTION EXPOSURE - effected in two different ways, firstly by intradermal injections and secondly, one week later, by topical application over the
injection sites.
A) Intradermal injections
For this purpose an area of about 24 cm of dorsal skin in the scapular region was clipped free from hair with electric clippers.
Pairs of intradermal injections (0.1 ml each) were made simultaneously in the clipped area as shown in Fig. 1. The following preparations were injected:
* test animals
- two injections with Freund's Complete Adjuvant (FCA)
- two injections with a 0.03% dilution of monobromoacetic acid in demiwater
- two injections with a 0.03% dilution of monobromoacetic acid in demiwater and FeA (1:1)
* control animals
- two injections with FCA
- two injections with demi-water
- two injections with FCA and demi-water (1:1)
Skin readings were made at 24 hours after the treatment.

B) Topical application
One week after the intradermal injections, the dorsal skin in the scapular region of the test and control animals was closely shaved again. The
induction by topical application was also made in this region.
The test animals were treated as follows:
A circa 2 x 4 cm patch of Whatman No. 3 MM filter paper was loaded with a 5% dilution of the test substance in demi-water. The loaded patch was
placed over the sites of the intradermal injections and secured. The dressing was left in place for 24 hours.
The control animals were similarly treated with patches moistened with demi-water. Skin readings were made directly after removal of the patches.

B. CHALLENGE EXPOSURE
The topical challenge was carried out two weeks after the topical induction.
An area of circa 5 x 5 cm on the right flank of each test and control animal was clipped free from hair. Patches were loaded with a 1% dilution of the test substance in demi-water. One loaded patch was placed separately on the clipped area of the flank of each test and control animal. The patch was covered with Leukopor bandage, and held in place by Tensoplast for 24 hours.
Skin readings were made at 24 and 48 hours after removal of the patch.

Positive control substance(s):

yes

Remarks:

2,4-dinitrochlorobenzene (DNCB)

Positive control results:

Control group DNCB: induction: 0.1% in maize oil and FCA maiz oil 1:1. Topical application: 0.1% in vaseline.
Skin reactions after patch removal: erythema grade 2 in 5/10 animals, erythema grade 1 in 4/10 animals. No skin reaction in 1 animal. No oedema.
Challenge 0.05% DNCB in vaseline: skin reactions after 24 h: erythema grade 3 in 2/10 animals, erythema grade 2 7/10 animals, erythema grade 1 in one animal. Oedema grade grade 3 in 2/10 animals, grade 2 in 5/10 animals, grade 1 2/10 animals 0 in one animal.
48 h after challenge expsoure: erythema grade 3 1/10 animals, grade 2 8/10, grade 1 1/10. Oedema grade 3 2/10, grade 2: 6/10 and grade 12/10 animals.

The positive control showed very clear positive skin reactions after the challenge application and confirmed the sensitivity of the test system.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

1 % in water

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 1 % in water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

1% in water

No. with + reactions:

0

Total no. in group:

9

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 1% in water. No with. + reactions: 0.0. Total no. in groups: 9.0.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1% in water

No. with + reactions:

11

Total no. in group:

18

Clinical observations:

incrustation observed in 2 animals 2 deaths for unknown reasons

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 1% in water. No with. + reactions: 11.0. Total no. in groups: 18.0. Clinical observations: incrustation observed in 2 animals 2 deaths for unknown reasons.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1 % in water

No. with + reactions:

12

Total no. in group:

18

Clinical observations:

4 animals with incrustation, 2 with scaling

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 1 % in water. No with. + reactions: 12.0. Total no. in groups: 18.0. Clinical observations: 4 animals with incrustation, 2 with scaling.

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

DNCB 0.05% in vaseline

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

1 animal with a smll wound, one with incrustation

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: positive control. Dose level: DNCB 0.05% in vaseline. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: 1 animal with a smll wound, one with incrustation.

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.05% DNCB in vaseline

No. with + reactions:

10

Total no. in group:

10

Clinical observations:

scaliness in 10 animals, one with a small wound, one with incrustation

Remarks on result:

other: see Remark

Remarks:

Reading: 2nd reading. . Hours after challenge: 48.0. Group: positive control. Dose level: 0.05% DNCB in vaseline. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: scaliness in 10 animals, one with a small wound, one with incrustation.

* Preliminary test:

Dose selected to be the maximum dose without lethality. Treatment of the three animals with the 1% test dilution necrosis was observed (all three animals). 0.3% test dilution caused moderate erythema and abscesses (two animals), and necrosis (one animal). 0.1% dilution caused moderate erythema and abscesses (one animal only), the other two animals did not show any response. No signs of systemic toxicity were observed in any of the three animals. The degree of irritation observed with the lowest test dilution was considered too high. It was decided to use a 0.03% test dilution for intradermal treatment during the induction phase.

Topical treatment with the 10% test dilution induced moderate to severe erythema and very slight or slight oedema (all 3 animals). The next day, moderate erythema and very slight to moderate oedema were still observed. The 3% test dilution induced very slight or slight erythema (2 of 3 animals). The next day, slight erythema and very slight oedema was still observed (one animal). The 1% test

dilution induced very slight erythema (1 of 3 animals). The next day, no signs of skin irritation were observed.

It was decided to use a 5% test dilution for topical treatment during the induction phase, and a 1% test dilution for topical treatment during the challenge phase of the study.

* Induction:

The intradermal injections generally caused the following skin reactions:

test animals

- with FCA: moderate or severe erythema,

- with the 0.03% dilution of the test substance in demi-water: slight, moderate, or severe erythema and abscesses,

- with the 0.03% dilution of the test substance in a mixture of FCA and demi-water (1:1): moderate or severe erythema and abscesses, control animals

- with FCA: moderate or severe erythema,

- with demi-water: slight erythema,

- with the mixture of FCA and demi-water: moderate or severe erythema and abscesses (2 animals).

After the topical application of the moistened patches, no signs of skin irritation were observed in any of the 10 controls.

After the topical application of the 5% test dilution, very slight, slight or moderate erythema with or without very slight or slight oedema were observed in all test animals.

* Challenge:

When the skin reactions were scored at 24 hours after removal of the patches, it appeared that the bandages of one animal had not been removed. Therefore, the skin reactions of this animal were scored 24 hours after removal of the test patch only (exposure period = 48 hours). The challenge treatment with the 1% test dilution in demi-water induced very slight erythema in 2 controls only. At 48 hours after removal of the patches, none of the controls showed any skin reaction. In the test group, the challenge treatment with the 1% test dilution in demi-water induced very slight erythema in 2 animals and moderate or severe erythema with or without very slight, slight, or moderate oedema in 9 animals. Two animals showed incrustation. At 48 hours after removal of the patches, very slight erythema was observed in 5 animals and moderate or severe erythema with or without very slight, slight, or moderate oedema in 7 animals. Scaliness was observed in one animal and incrustation in 4 animals.

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

11/18 and 12/18 test animals (>50%) showed very distinct skin reactions after the challenge, whereas at the same time only two controls showed a very weak skin response. Therefore, the skin effects observed in the test group were considered as positive signs of sensitization. Because, more than 30% of the test animals reacted positively, it was concluded that under the conditions of this study and according to the EEC-standards (mentioned in EEC-Directive 83/467/EEC and published in the Official Journal of the European communities, L 257, Volume 26, 16 September 1983), Bromoacetic acid is a sensitizer.
Consequently, Bromoacetic acid is classified as R43: May cause sensitization by skin contact. According to regulation EC No. 1272/2008 and amenmends the substance is classified as skin sensitizer category 1.

Executive summary:

A guinea pig maximisation test was performed with 20 test (10 per sex) and 10 (5 per sex) negative and positiv control guinea respectively. The maximum non-irritant concentration was determiend in a pretest. However in the main test very severe skin reactions were observed during the topical induction phase. Due to the corrosive properties of the test substance this may have compromised the outcome of the test. 2 test animals died for unknown reasons on day 8 of the study. The positive control showed the expected positive reactions. In the test substance group skinreactions after 24 and 48 h after the challenge application were observed in 11 and 12 of 18 test animals. 2 of 10 negative controls showed a positive skin reaction at the 24 h reading. consequently the substance is clssified as a skin sensitizer. Due to the uncertainties of the skin reactions being perhaps related to the corrosivity of the substance, a categorisation in a subcategory is not proposed based on these data.

According to regulation EC No. 1272/2008 and amenmends the substance is classified as skin sensitizer category 1.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

A guinea pig maximisation test was performed with 20 test (10 per sex) and 10 (5 per sex) negative and positiv control guinea respectively. The maximum non-irritant concentration was determiend in a pretest. However in the main test very severe skin reactions were observed during the topical induction phase. Due to the corrosive properties of the test substance this may have compromised the outcome of the test. 2 test animals died for unknown reasons on day 8 of the study. The positive control showed the expected positive reactions. In the test substance group skinreactions after 24 and 48 h after the challenge application were observed in 11 and 12 of 18 test animals. 2 of 10 negative controls showed a positive skin reaction at the 24 h reading. consequently the substance is clssified as a skin sensitizer. Due to the uncertainties of the skin reactions being perhaps related to the corrosivity of the substance, a categorisation in a subcategory is not proposed based on these data.

According to regulation EC No. 1272/2008 and amenmends the substance is classified as skin sensitizer category 1.

Migrated from Short description of key information:
The test substance gave a positive reaction in a guniea pig maximisation test. However, due to the corrosive nature of the substance and svere skin reactions at the topical induction phase, the test may have over estimated the skin senstization potential of Bromo acetic acid. Based on this information th substance is classified as skin sensitizer category 1. Due to the corrosivity of the substance an allocation to a subgroup A or B according to regulation EU 286/2011 is not considered appropriate.

Justification for selection of skin sensitisation endpoint:
A guideline compliant Guinea pig maximisation test was performed with the test substance and indeicated a positive response.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Justification for selection of respiratory sensitisation endpoint:
No cases of respiratory sensitisation have been reported. Due to the corrosivity of the substance inhalation exposure is avoided.