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Administrative data

Link to relevant study record(s)

Description of key information

The substance is considered to be too poorly soluble for systemic uptake. This is supported by absence of toxicity in all available toxicity studies.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

The toxicokinetic assessment is based on experimental data on physico-chemical properties and toxicological properties of Pigment Yellow 139 and its semi-condensate Pigment Yellow 185. Pigment Yellow 139 contains two barbituric acid moieties whereas Pigment Yellow 185 contains only one. The other moiety is the open, not fused “semi-condensate” form. An overview on the properties is given in the tables below.

As can be expected from the chemical structures, both pigments have a similar molecular weight (368 and 337 g/mol), and a similar relative density. They decompose at temperatures > 380°C prior to melting.

Both are of very low solubility in both water and octanol. From these solubilities, a Low POW of 0.31 was calculated for Pigment Yellow 139.

 

As the substances are so insoluble, no experimental data on abiotic hydrolysis is available.

 

Both molecules consist highly conjugated systems that give the molecule a rigid form.

 

Both general poor solubility and unflexible form impair transport across biological membranes. Absence of systemic uptake was indirectly seen by absence of toxicity in any of the available toxicity studies. Also no test-item induced coloration of internal tissues was observed upon necropsy after acute and subacute gavage dosing at the limit dose level.

 

Overall, uptake after ingestion, inhalation and skin contact is not expected.

 

Accordingly, metabolism and distribution cannot be considered and elimination is restricted to gastrointestinal passage. Inertness is also indicated from the very low toxicity upon intraperitoneal injection of a high dose (6400 mg/kg bw for PY 139 and 2000 mg/kg bw for PY 185). During the one-weak observation period, no animal died.

 

Should any substance be taken up, bioaccumulation is not possible since the substance is not soluble in octanol and therefore in fat.

 

PY 139

PY 185

36888-99-0

76199-85-4

Molecular weight

367.27 g/mol

337.29 g/mol

State of the substance at 20°C and 101.3 kPa

orange powder

yellow powder

Melting point

>460°C at 1013 hPa

Decomposes at 380°C before melting.

Boiling point

Not applicable (decomposes before boiling)

Not applicable (decomposes before boiling)

Relative densitiy

1.73 g/cm³

1.50 g/cm³

Vapour pressure

0.000001 hPa

< 0.000001 hPa

Log Pow (calculated from solubilities)

0.31

Water solubility

2.9 µg/L

< 10 µg/L

n-octanol solubility

5.9 µg/L

< 0.3 mg/L

Surface tension

Not surface active: The water solubility is below 0.1 mg/L.

Not surface active: The water solubility is < 1 mg/L.

Flash point

Not relevant

Not relevant

Auto flammability/self-ignition temperature

400°C at 1013 hPa

359°C at 1013 hPa

Flammability

Non flammable

Non flammable

Explosive properties

Non explosive

Non explosive

Oxidising properties

No oxidizing properties

No oxidizing properties

Dissociation constant

Not applicable

Not applicable

 

PY 139

PY 185

36888-99-0

76199-85-4

Skin and eye irritation

Not irritating

K1

Not irritating

K2/1

Skin sensitzation

Not sensitizing

K1

Not sensitizing

K1

acute oral tox (LD50 in mg/kg bw)

> 10000

K2

> 5000

K1

acute dermal tox (LD50 in mg/kg bw)

> 2500

K2

acute inhalation tox

LC50 > 5.42 mg/L

K1

Subacute toxicity

NOAEL = 1000

K2

Bacterial mutagenicity

Non mutagenic

K2

Non mutagenic

K1

Clastogenicity in vitro

 Non clastogenic

K1

Mutagenicity in mammalian cells in vitro

Non mutagenic

K1

Genetic toxicitiy

in vivo - micronucleus test

Non genotoxic

K1

Toxicity to reproduction

(OECD 421)

NOAEL = 1000

K1

 acute toxicity upon intraperitoneal injection  No mortality at 6400 mg/kg bw  No mortality at 2000 mg/kg bw