Phosphorous acid, mixed 2,4-bis(1-methyl-1-phenylethyl)phenyl and isodecyl and 2-(1-methyl-1-phenylethyl)phenyl and 4-(1-methyl-1-phenylethyl)phenyl and phenol triesters)

Endpoint summary

Description of key information

Triisodecyl phosphite (TDP) was test using the LLNA assay at concentrations of 25%, 50%, and 100%. It was positive at all test concentrations. The calculated EC3 value is 20.1%. The TDP results suggest that DP 374 should be classified as a skin sensitiser, 1B (i.e. not a strong skin sensitiser). In addition, hte

Local lymph node assay (LLNA) study of diisodecyl phenyl phosphite (Sanders 2010) showed positive responses at 50% and 100% concentrations. EC3 value was determined to be 40.6%

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

The animals were acclimatised for a period of at least 5 days, after which animals were selected at random and given a unique number marked on their tail. At the start of the study the animals weighed in the range of 15 to 23 grams and were 8-12 weeks in age.

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

25%, 50%, 100%

No. of animals per dose:

4

Details on study design:

Five days following the first topical applications, all mice were injected via the tail vein with 250 uL of phosphate buffered saline (PBS) containing 3H-methyl thymidine (3HTdR) giving a total of 20 uCi to each mouse.

Statistics:

EC3= 20%; based on a regression analysis of the dose groups. All dose groups were positive, but there was sufficient dose-response to determine an EC3.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: vehicle 14023.98 25% 53667.32 50% 103195.40 100% 137149.20

Concentration	dpm/node	Test / Control Ratio
Vehicle (acetone/olive oil 4:1)	1753.00	N/A
25%	6708.42	3.83
50%	12899.43	7.36
100%	17143.65	9.78
EC3= 20%

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Test substance was postive (ratio >3) at concentrations of 25, 50, and 100%. An EC3 was determined to be 20%. The results indicated that TDP is a skin sensitiser, but not a strong skin sensitiser.

Executive summary:

TDP was test using the LLNA assay at concentrations of 25%, 50%, and 100%. It was positive at all test concentrations. The calculated EC3 value is 20.1%. The results suggest that TDP should be classified as a skin sensitiser, but not a strong skin sensitiser.

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP, guideline study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

CBA/Ca female mice, nulliparious and non-pregnant. 5 day acclimatisation peroiod. At the start of the study the animals were 8-12 weeks old.

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

0, 25, 50, 100%

No. of animals per dose:

4

Details on study design:

A preliminary screening test was done to ascertain the systemic toxicity/irritancy potential of the test material. Based on these results, the top dose was set at 100% (neat material), followed by lower doses at 25% and 50% dilutions in an acetone/olive oil (4:1) mixture.

Parameter:

SI

Value:

2.34

Test group / Remarks:

25% concentration

Parameter:

SI

Value:

3.4

Test group / Remarks:

50% concentration

Parameter:

SI

Value:

6.3

Test group / Remarks:

100% concentration

Parameter:

EC3

Value:

0.406

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: 0% (Vehicle) - 1399.81 25% - 3270.49 50% - 4763.82 100% - 8825.35

Conc	dpm/ node	Test / Control Ratio	Result
Blank	1399.81	N/A	N/A
25%	3270.49	2.34	Negative
50%	4763.82	3.40	Positive
100%	8825.35	6.30	Positive
EC3 value = 40.6% The draft report is in preparation.

Interpretation of results:

sensitising

Remarks:

Migrated information

Conclusions:

Weston PDDP was sensitising at concentrations of 50% and 100%. The EC3 value is 40.6% from this study.

Executive summary:

While this study indicated that Weston PDDP is a skin sensitiser, the relatively high EC3 value (40.6%) indicates that this substance is not a strong skin sensitiser.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Justification for classification or non-classification

Classified as a skin sensitizer based on the positive LLNA study.