1,3-Propanediol, 2,2-dimethyl-, C5-9 carboxylates

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Justification for grouping of substances and read-across

There is reliable human data namely a Repeated Insult Patch Test (RIPT) available for the skin sensitisation potential of the target substance 1,3-Propanediol, 2,2-dimethyl-, C5-9 carboxylates (CAS 85711-80-4). To strenghten the obtained result further read-across from structurally related substances was conducted in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, using studies fulfilling the standard information requirements set out in Annex VII, 8.3.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met." In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006, whereby toxicological properties may be predicted from data for the reference substance(s) on the basis of structural similarity, the substances Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS 68855-18-5), and 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) are selected as source substances for hazard assessment following a weight-of-evidence approach based on structural analogues.

Human data

A realiable Repeated Insult Patch Test (RIPT, RL2) was conducted to evaluate the skin sensitising potential of 1,3-Propanediol, 2,2-dimethyl-, C5-9 carboxylates (CAS 85711-80-4) (Stolman, 1998).

In total, 113 volunteers were included in the test. 98 volunteers completed the study. 0.2 mL of the test substance was topically applied to the skin and covered by an occlusive tape. For induction, a series of 9 patchings were performed on the left scapular area over a period of three weeks. At each occasion, the patch was held in place for 24 hours. A 24 hour period, during which no test material was applied, followed the weekday patch removals; a 48 hour period followed the weekend patch removal. After the last patchings, a two-week rest period was included during which no test material was topically applied, followed by the last induction patching. For challenge, the patch was applied to untreated skin (right scapular area) for 24 hours. 48, 72 and 96 hours after challenge application, skin reactions were scored and recorded at the original induction test site (left scapular area) and each subject queried as to whether any reaction was experienced.

Based on the obtained results, the test substance did not induce signs indicative for contact dermal sensitisation in human subjects.

CAS 131459-39-7

A Guinea Pig Maximisation Test was performed with 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) according to OECD Guideline 406 (Allen, 1999). 10 male Dunkin-Hartley guinea pigs were treated with the test substance and compared with 4 negative control animals. Sensitivity of the used animal strain was periodically tested using the positive control substance PEG 400 70:30 8(in acetone). A 25% dilution of the test substance in arachis oil was used for intradermal induction. For epidermal induction, undiluted test material was used. 14 days after the last induction treatment, all animals were challenged epicutaneously with either 75 or 100% test substance. 24 and 48 hours after challenge exposure, all skin examination scores were zero in all test and negative control animals. Based on the obtained results, the test substance is not considered to exhibit skin sensitising properties.

CAS 68855-18-5

The skin sensitisation potential of Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS 68855-18-5) was evaluated in guinea pigs with a Buehler test for skin sensitisation performed according to OECD 406 under GLP conditions (Doyle, 1996). 20 male Dunkin-Hartley guinea pigs were treated with the test substance and compared to 10 male control animals. Three epidermal inductions were performed with 100% test substance in weekly intervals for 6 hours under occlusive conditions. 14 days after the last induction treatment, all animals were challenged for 6 hours epicutaneously with 100% (left top flank) and 30% (right top flank) test substance (diluted in corn oil) under occlusive conditions. Animals were evaluated for skin reactions 24 and 48 h after challenge. 1/20 animals (5%) of the test group responded to the challenge with 100% test substance formulation with scattered mild redness 24 h after challenge, which was reversible until the second reading after 48 h. No further signs for irritation or sensitisation were observed during induction and challenge of the animals. The test item is considered not to be sensitising to the skin of guinea pigs under the conditions of the test.

Conclusion for skin sensitization

Following a weight-of-evidence approach based on animal data obtained for the structural analogue substances 3,5,5-trimethylhexanoic acid mixed tetraesters with pentaerythritol and valeric acid (CAS 131459-39-7) and Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS 68855-18-5) combined with results of a human patch test obtained for the target substance, 1,3-Propanediol, 2,2-dimethyl-, C5-9 carboxylates (CAS 85711-80-4) is not considered to exhibit skin sensitising properties.

 

Migrated from Short description of key information:
Skin sensitisation (OECD 406): not sensitising, analogue approach
RIPT in humans: not sensitising

Justification for selection of skin sensitisation endpoint:
Hazard assessment is conducted by means of read-across from structural analogues. The selected studies are all adequate and reliable studies based on the identified similarities in structure and intrinsic properties between source and target substance and overall quality assessment (refer to the endpoint discussion for further details).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Justification for selection of respiratory sensitisation endpoint:
Study not required according to Annex VII - X of Regulation (EC) No 1907/2006.

Justification for classification or non-classification

Based on read-across from structurally similar substances, the available data on skin sensitisation do not meet the classification criteria according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.