3,3'-thiodi(propionic acid)

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The data were derived from a secondary source (Cosmetic Ingredient Review (CIR) report) without access to original data. However, the data were peer-reviewed by an expert panel and the information presented is generally accepted as scientifically valid.

Data source

Reference

Reference 1

Reference Type:

secondary source

Title:

Final Safety Assessment of Thiodipropionic Acid and Its Dialkyl Esters as Used in Cosmetics

Author:

Diamante, C. et al.

Year:

2010

Bibliographic source:

Int J Toxicol 29(supp 3):137S-150S

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

2004

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Principles of method if other than guideline:

A maximization test was performed on 26 subjects. 5 repeats of SLS and test material patches were applied to a site on the upper outer arm, volar forearm, or back of each subject under occlusive conditions.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

3,3'-thiodi(propionic acid)

EC Number:

203-841-3

EC Name:

3,3'-thiodi(propionic acid)

Cas Number:

111-17-1

Molecular formula:

C6H10O4S

IUPAC Name:

3-[(2-carboxyethyl)sulfanyl]propanoic acid

Details on test material:

- Name of test material (as cited in study report): Thiodipropionic acid (TDPA), 3,3’-thiodipropionic acid; bis(2-carboxyethyl) sulfide; ß,ß-thiodipropionic acid; 3,3’-thiobis(propanoic acid); 4-thiaheptanedioic acid; diethyl sulfide 2,2’-dicarboxylic acid; thiodihydracrylic acid
- Analytical purity: 2% in face cream formulation

Method

Type of population:

general

Subjects:

- Number of subjects exposed: 26
- Sex: male (9) and female (17)
- Other: One subject did not complete the study for non-test article-related reasons (25 subjects therefore completed the study)

Controls:

none

Route of administration:

dermal

Details on study design:

TYPE OF TEST(S) USED: patch test (epicutaneous test): maximization test

ADMINISTRATION
Induction Phase: During the induction phase, 0.5 mL of 0.25% SLS was applied to a site on the upper outer arm, volar forearm, or back of each subject under an occlusive patch for 24 h. Upon removal of the SLS patch, an occlusive patch containing 0.05 mL of the face cream containing 2% of Thiodipropionic acid (TDPA) was applied to the same site for 48 h (or 72 h on the weekends). The site was examined upon patch removal. If no irritation were present, the same SLS patch test patch sequence was repeated. This continued for a total of 5 induction exposures. If irritation developed at any point of the induction phase, the SLS patch was omitted.
Challange: After a 10-day nontreatment period, the challenge was performed in which a previously untreated site was pretreated with an occlusive patch of 0.5 mL of 5% SLS for 1 h followed by an occlusive 48 h patch containing 0.05 mL of the face cream containing 2% of Thiodipropionic acid (TDPA).

EXAMINATIONS
The challenge site was graded on a scale of 0 to 3 at 15 - 30 min and 24 h after patch removal.

Results and discussion

Results of examinations:

NO. OF PERSONS WITH/OUT REACTIONS COMPARED TO STUDY POPULATION
- Number of subjects with positive reactions: 0
- Number of subjects with negative reactions: 25
- Number of subjects with equivocal reactions: 0
- Number of subjects with irritating reactions: 0

OTHER RESULTS:
Of the remaining 25 subjects, no adverse or unexpected reactions were observed during the induction phase, and no evidence of sensitization was seen at challenge. The researchers concluded that a face cream containing 2% TDPA did “not possess a detectable contact-sensitizing potential.”