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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Read-across of data from guideline studies.
Justification for type of information:
MTDID 22327 is a member of the Perfluorinated Organic Chemicals, C5-C18, category. Unlike most members of the category, MTDID 22327 is a UVCB consisting mostly of perfluoro-N-methylmorpholine, a mixture of C5-C7 perfluoroamines, and perfluorohexane isomers. However, all of these chemicals stem from the same manufacturing process, have similar physicochemical properties including high vapor pressure and low water solubility relative to the hydrocarbon analogs (e.g., hexanes v. perfluorohexanes), and also lack any chemically reactive groups, which forms the technical basis for the category.  Members of this category are fully fluorinated, meaning that fluorine, rather than hydrogen, is bonded to all carbon atoms in the molecule.  Fluorine is the most electronegative of the elements (fluorine has an electronegativity of 3.98 on the Pauling scale, as compared to 2.55 for carbon, 3.04 for nitrogen or 2.20 for hydrogen).  This electronegativity is expected to dominate over all other aspects of substance chemistry and is the underlying basis for similarity of substances in this category.  For example, strong electron withdrawing in perfluorinated tertiary amines results in a molecule with essentially no lone pair influence, and which has chemistry more similar to a branched, perfluorinated alkane than any other structure.  Because these substances exhibit similar physicochemical properties they can be considered to constitute a chemical category. The data gap for acute oral lethality can therefore be addressed by many-to-one read-across between category members.

Because these substances exhibit similarity in their physicochemical properties and toxicological properties in mammals, and because available data indicates that parent molecules are not reactive toward biological molecules and cannot undergo bioactivation by normal enzymatic processes, they can be considered to constitute a chemical category. Data gaps for partitioning properties, mammalian and ecological toxicity can therefore be addressed by read-across and/or trend analysis between category members.  The readacross is considered reliable with restrictions and the result is suitable for use in Risk Assessment, Classification & Labelling, and PBT Analysis. See section 13 for a fuller discussion of the category approach.

Data source

Reference
Reference Type:
other: Read-across from other internal studies
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: REACH Guidance on QSARs and grouping of chemicals
Version / remarks:
May/July 2008
Deviations:
no
GLP compliance:
no
Remarks:
Source studies were conducted under GLP conditions.

Test material

Constituent 1
Reference substance name:
Reaction mass of perfluoro(dimethyl - N - Butylamine ) and perfluoro (methyl - di - N - propylamine) and perfluoro (dimethyl - N - propylamine and 2,2,3,3,5,5,6,6, octafluoro-4-(trifluoromethyl)morpholine and perfluoro-N-pentane
EC Number:
908-205-5
Cas Number:
2187449-42-7
IUPAC Name:
Reaction mass of perfluoro(dimethyl - N - Butylamine ) and perfluoro (methyl - di - N - propylamine) and perfluoro (dimethyl - N - propylamine and 2,2,3,3,5,5,6,6, octafluoro-4-(trifluoromethyl)morpholine and perfluoro-N-pentane
Specific details on test material used for the study:
Read-across from category members:
∙Perfluorohexanes, CAS# 1064697-81-9
∙Perfluoroheptanes, CAS# 1064698-16-3
∙Perfluorotributyl amines, CAS# 1064698-37-8
∙Perfluorotripropylamine, CAS# 338-83-0
∙Perfluoro-N-methylmorpholine, CAS# 382-28-5
∙Perfluoro-N-C1,3-alkyl morpholines, CAS# 1093615-61-2

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Remarks on result:
other: Oral LD50 values of category members range from > 2000 mg/kg to > 10000 mg/kg.

Any other information on results incl. tables

Acute oral toxicity studies were performed with rats on category members.  Rats were dosed with the category members by oral gavage.  Animals were observed 4 times during the first day postdose and then once daily for 14 days.  After the observation period, all animals were euthanized and examined for gross pathology.  All animals survived.  There were no abnormal clinical observations, body weight changes or necropsy findings in any animals.  Based on these results the category members have an LD50 value greater than 2000 mg/kg bw.

MTDID 22327 is a member of the Perfluorinated Organic Chemicals, C5-C18, category. Unlike most members of the category, MTDID 22327 is a UVCB consisting mostly of perfluoro-N-methylmorpholine, a mixture of C5-C7 perfluoroamines, and perfluorohexane isomers. However, all of these chemicals stem from the same manufacturing process, have similar physicochemical properties including high vapor pressure and low water solubility relative to the hydrocarbon analogs (e.g., hexanes v. perfluorohexanes), and also lack any chemically reactive groups, which forms the technical basis for the category.  Members of this category are fully fluorinated, meaning that fluorine, rather than hydrogen, is bonded to all carbon atoms in the molecule.  Fluorine is the most electronegative of the elements (fluorine has an electronegativity of 3.98 on the Pauling scale, as compared to 2.55 for carbon, 3.04 for nitrogen or 2.20 for hydrogen).  This electronegativity is expected to dominate over all other aspects of substance chemistry and is the underlying basis for similarity of substances in this category.  For example, strong electron withdrawing in perfluorinated tertiary amines results in a molecule with essentially no lone pair influence, and which has chemistry more similar to a branched, perfluorinated alkane than any other structure.  Because these substances exhibit similar physicochemical properties they can be considered to constitute a chemical category. The data gap for acute oral lethality can therefore be addressed by many-to-one read-across between category members.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The category (perfluorinated organic chemicals, C5-C18) has a rat acute oral LD50 value of greater than 2,000 mg/kg bw.
Executive summary:

Acute oral toxicity studies were performed with rats on category members.  Rats were dosed with the category members by oral gavage.  Animals were observed 4 times during the first day postdose and then once daily for 14 days.  After the observation period, all animals were euthanized and examined for gross pathology.  All animals survived.  There were no abnormal clinical observations, body weight changes or necropsy findings in any animals.  Based on these results the category members have an LD50 value greater than 2000 mg/kg bw.

Because these substances exhibit similarity in their physicochemical properties and toxicological properties in mammals, and because available data indicates that parent molecules are not reactive toward biological molecules and cannot undergo bioactivation by normal enzymatic processes, they can be considered to constitute a chemical category. Data gaps for partitioning properties, mammalian and ecological toxicity can therefore be addressed by read-across and/or trend analysis between category members.  The readacross is considered reliable with restrictions and the result is suitable for use in Risk Assessment, Classification & Labelling, and PBT Analysis. See section 13 for a fuller discussion of the category approach.

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