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Exposure related observations in humans: other data

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exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Adopted according to OECD SIDS

Data source

Reference Type:
study report
Report date:

Materials and methods

Type of study / information:
Human skin irritation and sensitization
Endpoint addressed:
skin irritation / corrosion
skin sensitisation
Principles of method if other than guideline:
Repeated insult patch tests
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Ammonium mercaptoacetate
EC Number:
EC Name:
Ammonium mercaptoacetate
Cas Number:
Molecular formula:
ammonium sulfanylacetate
Details on test material:
- Name of test material (as cited in study report): Ammonium thioglycolate
- Analytical purity: no data


Details on study design:
Repeated insult patch tests were used to evaluate the skin irritation and sensitization potential of 14.4% Ammonium Thioglycolate in a total of 240 subjects (32 males, 208 females, 18-69 years old). A panel of 240 subjects was patch tested with 14.4% Ammonium Thioglycolate. On Mondays, Wednesdays, and Fridays, the test substance was applied (0.2 ml, semi-occlusive patch) for 24 h to an area, between the scapulae and waist, adjacent to the midline. New sites were used for subsequent induction patch applications.

Patch removals on Tuesday and Thursday were each followed by a 24 h non-treatment period, and removals on Saturday by a 48 h non-treatment period. Each site was scored prior to application of the next patch according to the scale: 0 (no evidence of any effect) to 4 (severe, defined as deep-red erythema with/without vesiculation or weeping). The test procedure was repeated for a total of nine applications.

After a 15 to 19 day nontreatment period, challenge patches were applied to new test sites. Reactions were scored at 24 and 48 h post-application. Any subject with a reaction during the challenge phase that was stronger than mild erythema (score = 1) was rechallenged 28 days later at a new test site.
Exposure assessment:
not specified

Results and discussion

A total of 20 subjects withdrew from the study, during induction phase, for reasons that were unrelated to treatment. Four of the subjects who withdrew had reactions to 14.4% Ammonium Thioglycolate: barely perceptible erythema (2 subjects), mild erythema with mild oedema (1 subject), and moderate erythema (1 subject). Of the 220 subjects who completed the study, 4 were not available for 24 h challenge readings.

In these subjects, reactions were not observed during 48 h challenge readings nor during the induction phase. Twelve of the 220 subjects had reactions to 14.4% Ammonium Thioglycolate only during the induction phase. Reactions classified as barely perceptible erythema score = +) predominated. Stronger reactions were observed in 3 subjects: 1 subject with mild erythema (score = 1) and 2 subjects with moderate erythema (score = 2). Reactions to not more than two induction applications were observed. Seven subjects had reactions to 14.4% Ammonium Thioglycolate only during the challenge phase. Reactions classified as barely perceptible erythema predominated. A stronger reaction, moderate erythema with mild oedema (score = 2e; 48 h reading), was observed in 1 subject. Reactions were not observed after the second challenge.

Applicant's summary and conclusion

The authors concluded that 14.4% Ammonium Thioglycolate did not induce clinically meaningful irritation or any evidence of induced allergic contact dermatitis in human subject.