Merbromin

Endpoint summary

Description of key information

An Adjuvant patch testwas conducted on five male Hartley guinea pigs to examine the sensitization effects caused by the test chemical.

3 out of 5 guinea pigs were sensitized with the chemical with mean score of 2. Thus the chemical was considered to be sensitizing on skin of guinea pigs.

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed journal.

Qualifier:

according to guideline

Guideline:

other: An Adjuvant patch tes

Principles of method if other than guideline:

An Adjuvant patch test was conducted on five male Hartley guinea pigs to examine the sensitization effects caused by the test chemical

GLP compliance:

not specified

Type of study:

other: Adjuvant patch test

Justification for non-LLNA method:

not specified

Species:

guinea pig

Strain:

Hartley

Sex:

male

Details on test animals and environmental conditions:

- Source: Funabashi Experimental Animal farm
- Age at study initiation: 400-500 kg

Route:

epicutaneous, occlusive

Vehicle:

other: Distilled water

Concentration / amount:

2%

Day(s)/duration:

9 days

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

other: Distilled water

Concentration / amount:

2%

Day(s)/duration:

48 hours

Adequacy of challenge:

not specified

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: no data
- Test groups: 5 male
- Control group: yes
- Site: shaved and abraded area of 2 × 4 cm2 nuchal skin, which was defined by 4 injections (0.1mlX4) of emulsified Freund’s complete adjuvant (FCA) at the corners.
- Frequency of applications: daily for 3 days and repeated on 9th day
- Duration: 9 days
- Concentrations: 2% (0.1 ml)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge:3 weeks
- Exposure period: 48 hours
- Test groups: 5
- Control group: yes
- Site: shaved skin of flank
- Concentrations: 2%
- Evaluation (hr after challenge): after 4 hours

Challenge controls:

Yes concurrent vehicle

Positive control substance(s):

not specified

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2%

No. with + reactions:

3

Total no. in group:

5

Clinical observations:

3 out of 5 guinea pigs were sensitized with the chemical with mean score of 2.

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

other: sensitizing

Conclusions:

3 out of 5 guinea pigs were sensitized with the chemical with mean score of 2.. Thus the chemical was considered to be sensitizing on skin of guinea pigs.

Executive summary:

An Adjuvant patch testwas conducted on five male Hartley guinea pigs to examine the sensitization effects caused by the test chemical

 

The method was described by the Sato et al. and it was a modification of maximization test. The guinea pigs were given single doses of 0.1 ml 2 % merbromin in water, applied occlusively, daily for 3 days on shaved and abraded area of 2 × 4 cm²nuchal skin at the corners of which were 4 FCA injection sites (each FCA injection: 0.1 ml). The epicutaneous treatment was repeated on day 9. On provocation 3 weeks after the beginning of the induction treatment, the guinea pigs were challenged topically with o.o1ml of chemical in distilled water directly to the shaved skin of the flank. Skin reactions were scored after 48 hours.A score greater than 2 was considered positive. The result was expressed as the mean score and frequency of positives. The Wilcoxon-Mann-Whitney test was used for statistical evaluation of the results.

 

3 out of 5 guinea pigs were sensitized with the chemical with mean score of 2. Thus the chemical was considered to be sensitizing on skin of guinea pigs.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Various studies have been reviewed to evaluate the dermal sensitization potential of the test chemical in living organisms. These include in vivo experimental studies on guinea pigs, humans for the test chemical. The results are summarized below:

An Adjuvant patch testwas conducted on five male Hartley guinea pigs to examine the sensitization effects caused by the test chemical

The method was described by the Sato et al. and it was a modification of maximization test. The guinea pigs were given single doses of 0.1 ml 2 % merbromin in water, applied occlusively, daily for 3 days on shaved and abraded area of 2 × 4 cm2nuchal skin at the corners of which were 4 FCA injection sites (each FCA injection: 0.1 ml). The epicutaneous treatment was repeated on day 9. On provocation 3 weeks after the beginning of the induction treatment, the guinea pigs were challenged topically with o.o1ml of chemical in distilled water directly to the shaved skin of the flank. Skin reactions were scored after 48 hours.A score greater than 2 was considered positive. The result was expressed as the mean score and frequency of positives. The Wilcoxon-Mann-Whitney test was used for statistical evaluation of the results.

3 out of 5 guinea pigs were sensitized with the chemical with mean score of 2. Thus the chemical was considered to be sensitizing on skin of guinea pigs.

This is supported by the results of a patch test carried out in eight patients suffering from the test chemical allergy. In this test, 2% of test chemical in water was exposed to the back of each patient and later readings were conducted according to International Contact Dermatitis Research Group guidelines after 2 and 4 days. If significant reactions occurred before, it was read immediately.

All six patients with delayed hypersensitivity to the test chemical showed only local reactions,  these reactions generally beginning 6 h after the application of the test chemical but patient 3 showed the reaction after 2 h. In four patients, important reactions at 24 h (DI) with the test chemical, In one of them (patient 8), there was even an intensive reaction (+++) at 6 h. As the 6 out of eight patients showed positive result, the test chemical was considered to be sensitizing on skin of eight patients suffering from test chemical allergy.

 

These results are lent support by Skin prick test (SPT) performed on eight patients suffering from test chemical allergy to assess the degree of contact sensitization.

About 2% of test chemical in water was applied to the forearms of each patient and the observed for skin lesions. The positive control was histamine (10 mg/ml).The longest and perpendicular diameters of the wheal were measured at 15 minutes, and patients were informed that if a late reaction developed, they must return for examination.

The SPT were positive, in immediate reading, only in patients 1 and 2 and exclusively with the test chemical, patient 1 showing a wheal of 10x6 mm (histamine 5x5) and patient 2 a wheal of 10x5 (histamine 8x5), In patients 4, 5, 6, and 7, the SPT with the test chemical, negative in immediate reading, gave a late eczematous reaction, patient 5 showing an intensive eczematous reaction at 12 h and the others at 24 h.

Hence, the test chemical can be considered to be sensitizing to skin.

These results are further supported by Patch-Test conducted on 54 children with contact dermatitis presumably induced by external agents to determine the contact sensitization reactions caused by the chemical.

All the patients were patch tested with ROC neodermotets at 2% of the test chemical and reactions were read at 48 hours. The concentration was generally recommended by the International Contact Dermatitis Research Group (ICDRG).

Of 54 children with contact dermatitis 15 reacted to 2 % of the test chemical. Hence, the test chemical was considered to be sensitizing on skin.

These results are also supported by a patch test performed on a 9-year-old girl with chemical to determine its skin sensitization potential.

The girl developed redness, swelling and itching on the 3rdfinger of her right hand and on her right cheek. The day before, she had a wart electro cauterized on this finger. After the procedure, her finger had been disinfected with the test chemical. For several years, she had previous application for wound disinfection, but had never complained of adverse side effects.

 When the dermatitis had cleared, the girl was patch tested with the GIRDCA standard series a concentration of 2% test chemical in water. Since she showed positive reaction after exposure with chemical, the test chemical was considered to be sensitizing on skin of 9 -year-old girl.

The above results are supported by a case study of a 28-year-old male fish-merchant who exposed to test chemical when he was treated for injuries on the foot and wrist.

He had no familial or personal precedents of any type of allergy or drug intolerance or any other clinical allergic pathology. His visit was precipitated by the difficulty his family doctor had in treating his wound. He did not tolerate any antiseptic or local antibiotic medication. Two episodes stand out from his clinical history (in 1972 and 1973) when he was treated for injuries on the foot and wrist.

When the test chemical was applied for the treatment of these wounds, they were complicated by the appearance of a violent local, peri-lesional eruption. Within a few hours the eruption extended, covering the entire skin. The erythematous, oedematous and vesicular eruption was complicated by facial and laryngeal oedema which required hospitalization and treatment in the Intensive Care Unit.

Since the man developed severe skin lesions, the test chemical was considered to be sensitizing on skin.

The above results are supported by a case study which reports of 15 patients with generalized rash, mostly appearing a day or two after breaking a clinical thermometer or during dental treatment were patch tested with chemical in which 11 patients had a previous history of contact dermatitis to the test chemical.

When these 11 patients were exposed to 2% of the test chemical, 5 patients (3 × 2+,2 × 1+) showed positive reactions after 72 hours. An inverted triangular or V-shaped erythema on both upper antero-medial thighs was a common feature. Severe cases had miliary pustules and/ or purpura on erythematous skin. Pruritus or burning sensation was relatively mild. Pyrexia or malaise was a complaint of more than half the patients.

Therefore the chemical was considered to be sensitizing on skin of patients.

Based on the available studies the test chemical is likely to cause dermal sensitization. Hence, the test chemical can be considered to a skin sensitizer. It can be classified under the category “Skin Sensitizer 1” as per CLP Regulation.

 

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available studies the test chemical is likely to cause dermal sensitization. Hence, the test chemical can be considered to a skin sensitizer. It can be classified under the category “Skin Sensitizer 1” as per CLP Regulation.