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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Workers - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
23.51 mg/m³
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
75
Modified dose descriptor starting point:
NOAEC
Value:
1 763 mg/m³
Explanation for the modification of the dose descriptor starting point:
Convert oral NOAEL to inhalation NOAEC: 1000 mg/kg/day x [1/0.38 x 1/1 x 6.7/10] = 1763 mg/m3
AF for dose response relationship:
1
Justification:
No adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for differences in duration of exposure:
6
Justification:
Default factor for subacute to chronic study extrapolation
AF for interspecies differences (allometric scaling):
1
Justification:
Already taken into account during the correction of starting point
AF for other interspecies differences:
2.5
Justification:
Default factor for remaining toxicodynamic differences
AF for intraspecies differences:
5
Justification:
Default factor for workers
AF for the quality of the whole database:
1
Justification:
Based on appropriate testing for tonnage, no adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - workers

2-6-di-tert-butyl-4-methylcyclohexyl 5-[bis(2-ethoxy-2-oxoethyl)carbamoyl]oxy-2-(4-tert-butylphenyl)-6-cyano-1H-pyrrolo[1,2-b][1,2,4]triazole-7-carboxylate (529A coupler, UC-141), is not acutely toxic in respect to the oral and dermal route, with LD50 values greater than 2000 mg/kg bw. 529A coupler is not acutely toxic following inhalation exposure with an LC50 values greater than 5 mg/L. No local effects following inhalation are expected to occur as 529A coupler is neither corrosive nor irritating to the skin, and was not irritating to the eye in an in vivo study. In addition, no sensitising potential was identified in a guinea pig maximisation test. Therefore, acute DNELs for systemic effects, or long-term or acute DNELs for local effects are not possible to define. It would also be unnecessary to set acute systemic DNELs for inhalation because Risk Management Measures are implemented in working places to assure that exposure, if any, remains below the long-term inhalation DNEL.

Based on results of in vitro studies 529A coupler is not considered to possess any genotoxic potential.

In an OECD 421 reproduction/developmental toxicity screen (Török-Bathó, 2014, gavage), and an OECD 407 repeat dose 28-day oral toxicity study (Hooiveld, 2004, gavage), no effects were observed at any time point up to the limit dose (1000 mg/kg bw/day). These studies were used as the starting point for DNEL setting.

Considering the extreme log Pow value (>11), the large molecular weight (>700) and that this material is an insoluble solid, virtually no oral absorption is anticipated (no toxicity was elicited in repeat dose oral gavage studies upto the limit dose). By extension, no measurable dermal absorption of this material is anticipated (In an OECD 402 acute dermal toxicity (Hooiveld, 2004, tested up to 2000 mg/kg bw), there were no effects observed that would give any indication that any dermal absorption had taken place) and dermal absorption is anticipated to be 0%. Therefore, a long-term dermal DNEL for systemic effects is not necessary as the material will not enter the body through the dermal route to any toxicologically significant levels.

A safety factor of 1 has been applied for the quality of the database based on appropriate testing for the tonnage and that no adverse effects were observed in the repeat dose, reproductive toxicity studies, or genetic toxicity studies.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
5.8 mg/m³
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
150
Modified dose descriptor starting point:
NOAEC
Value:
870 mg/m³
Explanation for the modification of the dose descriptor starting point:
Convert oral NOAEL to inhalation NOAEC: 1000 mg/kg/day x [1/1.15 x 1/1] = 870 mg/m3
AF for dose response relationship:
1
Justification:
No adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for differences in duration of exposure:
6
Justification:
Default factor for subacute to chronic study extrapolation
AF for interspecies differences (allometric scaling):
1
Justification:
Already taken into account during the correction of starting point
AF for other interspecies differences:
2.5
Justification:
Default factor for remaining toxicodynamic differences
AF for intraspecies differences:
10
Justification:
Default factor for general population
AF for the quality of the whole database:
1
Justification:
Based on appropriate testing for tonnage, no adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

Local effects

Long term exposure
Hazard assessment conclusion:
no hazard identified
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure
Hazard assessment conclusion:
DNEL (Derived No Effect Level)
Value:
1.67 mg/kg bw/day
Most sensitive endpoint:
developmental toxicity / teratogenicity
Route of original study:
Oral
DNEL related information
DNEL derivation method:
ECHA REACH Guidance
Overall assessment factor (AF):
600
Modified dose descriptor starting point:
NOAEL
Value:
1 000 mg/kg bw/day
Explanation for the modification of the dose descriptor starting point:
NOAEL: 1000 mg/kg bw/day
AF for dose response relationship:
1
Justification:
No adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for differences in duration of exposure:
6
Justification:
Default factor for subacute to chronic study extrapolation
AF for interspecies differences (allometric scaling):
4
Justification:
Default factor for extrapolating toxicokinetics from rat to human
AF for other interspecies differences:
2.5
Justification:
Default factor for remaining toxicodynamic differences
AF for intraspecies differences:
10
Justification:
Default factor for general population
AF for the quality of the whole database:
1
Justification:
Based on appropriate testing for tonnage, no adverse effects observed in repeat dose, reproductive toxicity studies, or genetox
AF for remaining uncertainties:
1
Justification:
No remaining uncertainties
Acute/short term exposure
Hazard assessment conclusion:
no hazard identified
DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:
no hazard identified

Additional information - General Population

2-6-di-tert-butyl-4-methylcyclohexyl 5-[bis(2-ethoxy-2-oxoethyl)carbamoyl]oxy-2-(4-tert-butylphenyl)-6-cyano-1H-pyrrolo[1,2-b][1,2,4]triazole-7-carboxylate (529A coupler, UC-141), is not acutely toxic in respect to the oral and dermal route, with LD50 values greater than 2000 mg/kg bw. 529A coupler is not acutely toxic following inhalation exposure with an LC50 values greater than 5 mg/L. No local effects following inhalation are expected to occur as 529A coupler is neither corrosive nor irritating to the skin, and was not irritating to the eye in an in vivo study. In addition, no sensitising potential was identified in a guinea pig maximisation test. Therefore, acute DNELs for systemic effects or long-term or acute DNELs for local effects are not possible to define.

Based on results of in vitro studies 529A coupler is not considered to possess any genotoxic potential.

In an OECD 421 reproduction/developmental toxicity screen (Török-Bathó, 2014, gavage), and an OECD 407 repeat dose 28-day oral toxicity study (Hooiveld, 2004, gavage), no effects were observed at any time point up to the limit dose (1000 mg/kg bw/day. These studies were used as the starting point for DNEL setting.

Considering the extreme log Pow value (>11), the large molecular weight and that this material is an insoluble solid, virtually no oral absorption is anticipated (no toxicity was elicited in repeat dose oral gavage studies upto the limit dose). By extension, no measurable dermal absorption of this material is anticipated. In an OECD 402 acute dermal toxicity (Hooiveld, 2004, tested up to 2000 mg/kg bw) there were no effects observed that would give any indication that any dermal absorption had taken place) and dermal absorption is anticipated to be 0%. Therefore, a long-term dermal DNEL for systemic effects is not necessary as the material will not enter the body through the dermal route to any toxicologically significant levels.

A safety factor of 1 has been applied for the quality of the database based on appropriate testing for the tonnage and that no adverse effects were observed in the repeat dose, reproductive toxicity studies, or genetic toxicity studies.