Amides, C16-18, N-[3-(dimethylamino)propyl]

Endpoint summary

Description of key information

Acute oral toxicity: LD50 > 2000 mg/kg bw, OECD Guideline 423, GLP compliant 
Acute dermal toxicity: LD50 > 2000 mg/kg bw, Appraisal of the Safety of Chemicals in Foods, Drugs & Cosmetics, pre-GLP; read-across from Amide, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl)  
Acute inhalation toxicity: not necessary due to exposure considerations 

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-10-09 to 2013-12-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Crj: CD(SD)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: Approx. 9 weeks
- Weight at study initiation: 215 - 241 g
- Fasting period before study:
- Housing: 3/cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 3°C
- Humidity (%): 55% ± 15%
- Air changes (per hr): 12-18 fold
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: To: 2013-10-23 to 2013-11-07

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 10% (w/w)
- Amount of vehicle (if gavage): 10 mL/kg b.w.

DOSAGE PREPARATION (if unusual):
2000 mg/kg bw were achieved by administration of two times 1000 mg/kg bw, since a 20% w/w formulation was not homogenous based on trial formulations.

Doses:

2000 mg/kg bw, given as 2 dosages of 1000 mg/kg bw within 24 hours. The first on t=0 and the second on t=3 hours. Multiple dosages given within 24 hours are regarded as a single dose

No. of animals per sex per dose:

6 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days - Frequency of observations: mortality: twice daily; clinical signs: before and immediately, 5, 15, 30 and 60 min, as well as 3, 6 and 24 hours after administration, followed once daily - Frequency of weighing: weekly - Necropsy of survivors performed: yes

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Remarks on result:

other: 2/6 animals died on day 3 and 4, respectively

Mortality:

2/6 animals died on day 3 and 4, respectively (one of three animals of each step)

Clinical signs:

other: Surviving animals showed no clinical signs

Gross pathology:

No pathological changes were observed at necropsy.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: other: CLP, EU GHS (Regulation (EC) No 1272/2008)

Conclusions:

The oral LD50 of C16-18 DMAPA amidoamine in female rats was > 2000 mg/kg bw.

Executive summary:

In an acute oral toxicity study according to OECD guideline 423, adopted 17 December 2001 and EU method B.1 tris, May 2008, 6 female, fasted, approx. 9 weeks old CD(SD) strain rats were given a single oral dose of C16-18 DMAPA amidoamine (Amides, C16-18 (even numbered), N-[(dimethylamino)propyl]) in Propylene glycol by gavage at a dose of 2000 mg/kg bw and observed for 14 days.

The test substance was administeredas 2 dosages of 1000 mg/kg bw within 24 hours. The first on t=0 and the second on t=3 hours. Multiple dosages given within 24 hours are regarded as a single dose.

1/3 animals of each step died on day 3 and 4, respectively. No other clinical signs were noted in any of the animals. All surviving animals gained the expected weight at the end of the study period. No pathological changes were observed at necropsy.

 

Oral LD50 (rat, females) > 2000  mg/kg bw

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

For justification for read-across see endpoint summary "Aquatic toxicity".

Reason / purpose for cross-reference:

read-across source

Statistics:

Not reported

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 other: g/kg bw

Remarks on result:

other: no mortality during the observation period

Mortality:

No deaths were observed.

Clinical signs:

other: All animals appeared normal throughout the 24 h exposure period and the 14 d post-exposure observation period.

Gross pathology:

Not reported

Other findings:

Not reported

None

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test, the dermal LD50 value of the analogue source test substance was found to be > 2000 mg/kg bw.

Executive summary:

A study was conducted to determine the acute dermal toxicity of the analogue source test substance amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl) in male/female albino rabbit. The procedure was the modification of the techniques described in Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics, compiled by the staff of the Division of Pharmacology, Food and Drug Administration.

2 g/kg bw of test material was applied (single application) to the abraded and intact skin of the test animals. The trunk of each animal was then encased in a sleeve of plasticized material to ensure contact of the test material for a 24 h period. Animals were observed immediately after dosing, and at 1, 6 and 24 h post-dosing. Following the 24 h exposure period, animals were observed for mortality, skin response and general behavior for 14 d.

No mortality was observed in this study. All animals appeared normal throughout the 24 h exposure period and the 14 d post-exposure observation period.

Under the conditions of the test, the dermal LD50 value was found to be > 2 g/kg bw.

It can be expected that the study results are also applicable to the target substance Amides, C16-18 (even numbered), N-[(dimethylamino)propyl].

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Acute oral toxicity data are available for the target substance C16-18 DMAPA amidoamine and for the source substance Stearic acid 3-(dimethylaminopropyl)amide. An acute dermal toxicity test is available with the source substance Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl). A justification for read-across is given below.

Acute oral toxicity

In an acute oral toxicity study according to OECD guideline 423, adopted 17 December 2001 and EU method B.1 tris, May 2008, 6 female, fasted, approx. 9 weeks old CD(SD) strain rats were given a single oral dose ofC16-18 DMAPA amidoamine(Amides, C16-18 (even numbered), N-[(dimethylamino)propyl]) in Propylene glycol by gavage at a dose of 2000 mg/kg bw and observed for 14 days.

The test substance was administered as 2 dosages of 1000 mg/kg bw within 24 hours. The first on t=0 and the second on t=3 hours. Multiple dosages given within 24 hours are regarded as a single dose.

1/3 animals of each step died on day 3 and 4, respectively. No other clinical signs were noted in any of the animals. All surviving animals gained the expected weight at the end of the study period. No pathological changes were observed at necropsy. Theoral LD50 (rat, females) was shown to be > 2000  mg/kg bw

 

Also the source substance used for read-across for the endpoints irritation, sensitisation, repeated dose toxicity, genetic toxicity and toxicity to reproduction , Stearic acid 3-(dimethylaminopropyl)amide, was of equally low oral toxicity as demonstrated by the following study on rats:

In an acute oral toxicity study according to OECD guideline 423, adopted 17 December 2001 and EU method B.1 tris, May 2008, 6 female, fasted, 8-9 weeks old Wistar strain rats were given a single oral dose of Stearic acid 3-(dimethylaminopropyl)amide in Propylene glycol by gavage at a dose of 2000 mg/kg bw and observed for 14 days.

The test substance was administered as 2 dosages of 1000 mg/kg bw within 24 hours. The first on t=0 and the second on t=3 hours. Multiple dosages given within 24 hours are regarded as a single dose.

2/6 animals died on day 2 and 3, respectively. Clinical signs shown by the animals found dead and surviving animals included lethargy, hunched posture, uncoordinated movements, piloerection, diarrhoea, chromodacryorrhoea, pallor, and/or ptosis.

The surviving animals had recovered from the symptoms between days 7 and 10.

The two animals found dead showed either slight weight gain or weight loss. 3/4 surviving females showed body weight loss between days 1 and 8. These animals again gained body weight between days 8 and 15. One surviving female showed body weight gain that was considered to be similar to that expected of normal untreated animals of the same age and strain.

One female found dead showed watery-turbid fluid in the stomach and watery-clear, yellowish fluid in the small intestines. The other female found dead showed a reduced size of the spleen. Pelvic dilation of the kidneys was noted in one surviving female. Other surviving females had no macroscopic abnormalities.Oral LD50 (rat, females) > 2000 mg/kg bw

 

Acute inhalation toxicity

Given that inhalation is not a relevant route of exposure, testing by the inhalation route is not necessary according to REACH Regulation Annex VIII 8.5.2 Column 2. Inhalation is not a relevant route of exposure to C16-18 DMAPA amidoamine. This applies to both workers and the general population and is due to the physicochemical properties of the substance and the nature of the products where it is used. C16-18 DMAPA amidoamine is a waxy solid paste. Generation of inhalable particles such as dust or aerosols is therefore not to be expected. Vaporisation needs not to be considered due to the substance’s very low vapour pressure of ca. 3.4E-08 Pa at 20°C. The generation of aerosols is excluded by technical means or product design. The substance is not used in spray applications. The most likely route of human exposure for workers and consumers is the dermal route. Results of laboratory animal studies show a low acute toxicity of closely related substances after oral and dermal exposure. Therefore the acute intrinsic toxic activity of C16-18 DMAPA amidoamine is considered to be low. The occurrence of a systemic toxicity relevant to humans after inhalation is unlikely and therefore the conduct of an acute inhalation toxicity study is unjustified.

 

Acute dermal toxicity

An acute dermal toxicity study has been conducted with the structurally similar substance Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl). This substance is structurally related toC16-18 DMAPA amidoamine and can be considered as a worst case due to more hydrophilic properties than C16-18 DMAPA amidoamine, which would favour dermal penetration.The test material (2000 mg/kg bw) was applied (single application) to the abraded and intact skin of male/female albino rabbits.The trunk of each animal was then encased in a sleeve of plasticized material to ensure contact of the test material for a 24 h period. Animals were observed immediately after dosing, and at 1, 6 and 24 h post-dosing. Following the 24 h exposure period, animals were observed for mortality, skin response and general behaviour for 14 d. No mortality was observed in this study. All animals appeared normal throughout the 24 h exposure period and the 14 d post-exposure observation period. Under the conditions of the test, the dermal LD50 value was found to be > 2000 mg/kg bw.

Endpoint conclusion

The testing of acute dermal toxicity of C16-18 DMAPA amidoamine is scientifically not justified as available reliable and relevant data from structurally related substances are used to fulfil this information requirement.

Based on the available information, the acute toxicity of C16-18 DMAPA amidoamine is low. There are no data gaps in acute toxicity. Even though there is no information on acute toxicity in humans, there is no reason to believe that the low acute toxicity observed in experimental animals would not be relevant for human health.

 

Justification for read-across

1. Read-across hypothesis and justification

This read-across is based on the hypothesis that source and target substances have similar toxicological properties because

they are manufactured from similar resp. identical precursors under similar conditions

the metabolism pathway leads to comparable products (amine backbone and long chain fatty acids) and non-common products predicted to have no toxicological effects (long chain fatty acids).

 

Therefore, read-across from the existing acute dermal toxicity study on the source substance is considered as an appropriate adaptation to the standard information requirements of Annex VIII 8.5.3 of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

 

The justification of the proposed read-across approach is elaborated in the next chapters.

 

2. Justification for read-across

 

2.1 Substance Identity

 

Table 1: Substance identities

	Source substance	Target substance
	Stearic acid 3-(dimethylaminopropyl)amide	C16-18 DMAPA amidoamine Amides, C16-18 (even numbered), N-[(dimethylamino)propyl])
	mono constituent substance	UVCB substance
CAS number	7651-02-7
Chain length distribution	< C16: < 1.6% C16: < 7% C18: > 89.8% > C18: < 1.6%	C14: <= 5 % C16: 25-35 % C18: >= 61 %
DMAPA	<0.002%	<=0.01%

 

Substance descriptions

The target substanceC16-18 DMAPA amidoamine is a UVCB substance manufactured from saturated C16-18 fatty acids and N, N-dimethylpropylenediamine (DMAPA). It is composed of C16 and C18 amides of DMAPA, with C18 being the larger part (>/= 61%)

 

The source substanceStearic acid 3-(dimethylaminopropyl)amide is manufactured from octadecanoic acid andN, N-dimethylpropylenediamine. It is composed of mainly C18 amides (> 89.8%) of DMAPA and small amounts of the C16 amide (<7%).

 

2.2 Common breakdown products

The source substance Stearic acid 3-(dimethylaminopropyl)amide is the main component of the UVCB target substanceC16-18 DMAPA amidoamine. The only difference is the chain length distribution: the target substance also contains a significant amount of the C16 amide.

This is not considered to be of relevance for metabolism.Both substances are amides which after resorption may be hydrolysed by amidases resulting in free fatty acids and DMAPA. The carboxylic acids then are further degraded by the mitochondrial beta-oxidation process (for details see common text books on biochemistry). The fatty acids enter normal metabolic pathways and are therefore indistinguishable from fatty acids from other sources including diet. The amine compounds are not expected to be further metabolised, but excreted via the urine mainly unchanged. 

 

2.3 Differences

The slight differences in fatty acid chain length (higher percentage of C16 in the target substance vs. corresponding higher percentage C18 in the source substance) are not considered to be of relevance for acute toxicity. This is proven by an equally low oral toxicity of > 2000 mg/kg bw for the source and target substances.

 

3. Physicochemical properties:

Table 2: Physicochemical properties

	Source substance		Target substance
Endpoints	Stearic acid 3-(dimethylaminopropyl)amide	Result	C16-18 DMAPA amidoamine	Result
Molecular weight		368.64 g/mol		340.59 - 368.64
Physical state at 20°C / 1013 hPa		Solid (paste)		Solid (waxy)
Melting point	OECD TG 102, RL1, non-GLP	67.4°C	OECD TG 102, RL1, non-GLP	41.8°C
Boiling point	OECD TG 103, RL1, non-GLP	412.3°C	OECD TG 103, RL1, non-GLP	320.5°C
Surface tension	ISO 4311, plate method, RL1, non-GLP	37.86 mN/m at 0.22 g/L	OECD TG 115, ring method, RL1, non-GLP	26.7 mN/m at 2.7 mg/L
Water solubility	OECD TG 105, RL1, non-GLP	10 mg/L at 20°C	OECD guideline 105/EU method A.6, slow stirring method/HPLC, RL1, non-GLP	3.65 mg/L at 23°C
Log Kow			Calculation (ACD/Labs Release 12.00, Product version 12.01 )	>6.6
	EU method A.8, calculation based on solubility in n-Octanol and water; RL2, non-GLP	2.01 at 20°C, pH7	Read-across from Stearic acid 3-(dimethylaminopropyl)amide
Vapour pressure	OECD TG 104, RL1, ISO17025 compliance	3.4E-08 Pa at 20°C	Read-across from Stearic acid 3-(dimethylaminopropyl)amide

 

4. Toxicokinetics

Based on the very close structural relationship no relevant differences in toxicokinetics are expected.The source substance Stearic acid 3-(dimethylaminopropyl)amide is the main component of the UVCB target substanceC16-18 DMAPA amidoamine. The only difference is the chain length distribution: the target substance also contains a significant amount of the C16 amide.

Experimental toxicokinetic studies are not available for either the source substanceStearic acid 3-(dimethylaminopropyl)amide or the target substanceC16-18 DMAPA amidoamine. Based on physicochemical data and molecular weight,an oral absorption rate of 100% is assumed as a worst case default value in the absence of other data.

In a study according to OECD guideline 414 with dermal application of the source substance Stearic acid 3-(dimethylaminopropyl)amide systemic effects (lower body weight and lower food consumption) were noted. Thus, in the absence of detailed dermal penetration data it has to be assumed that dermal penetration may occur, and a dermal absorption rate of 100% is assumed as a worst case default value based on the physicochemical properties and on experimental toxicological data.

 

Based on the structure, both substances are likely to undergo hydrolysis by amidases, which in general have a broad substrate specificity. Hydrolysis of Stearic acid 3-(dimethylaminopropyl)amide would result in Stearic acid and 3-Aminopropyldimethylamine. Hydrolysis of the target substanceC16-18 DMAPA amidoamine would additionally produce Palmitic acid.Stearic acid as well as palmitic acid are likely to enter the normal fatty acid metabolism and may be broken down to carbon dioxide or two carbon fragments, or be re-esterified to triacylglycerols and either metabolised for energy or stored in adipose tissue.

In general, lower primary aliphatic amines are metabolised to the corresponding carboxylic acid and urea. The tertiary site would be expected to undergo oxidation mediated bycytochrome P-450 or mixed function amine oxidases.

5. Comparison of data from human health endpoints

5.1 Toxicity data of the target and source substances

Table 3: General toxicological profiles forStearic acid 3-(dimethylaminopropyl)amide andC16-18 DMAPA amidoamine

	Source substance		Target substance
Endpoints	Stearic acid 3-(dimethylaminopropyl)amide	Result	C16-18 DMAPA amidoamine
Acute toxicity oral	OECD TG 423, RL1,GLP	LD50(rat) > 2000 mg/kg bw	LD50(rat) > 2000 mg/kg bw
Eye irritation	OECD TG 405, RL1, GLP	Category 1 (irreversible effects on the eye)	No data; read-across
	OECD TG 437, RL1, GLP	not severely irritating /not corrosive	No data; read-across
Skin irritation	OECD TG 439, RL1, GLP	not irritating	not irritating
	OECD TG 404, RL1, GLP	not irritating	No data; read-across
Sensitisation	OECD TG 406 (GPMT), RL1, GLP	not sensitising	No data; read-across
Genotoxicity	OECD TG 471, RL1, GLP	Negative	Negative
	OECD TG 467 (MLY), RL1, GLP	Negative	No data; read-across
	OECD TG 473 (Chromosome aberrations), RL1, GLP	Negative	No data; read-across
Repeated dose toxicity oral	Similar to OECD TG 407 (14 d DRF), rat, RL1, GLP	clinical signs/mortality (all animals at 500 mg/kg bw/d were sacrificed for humane reasons); haematology (slightly lower red blood cell and higher reticulocyte counts in males at 50 and 200 mg/kg bw/d); clinical biochemistry (higher ALAT activity in 2 males at 50 mg/kg bw/d, 2 males and 1 female at 200 mg/kg bw/d, higher alkaline phosphatase activity in 1 female at 200 mg/kg bw/d, higher potassium level in males at 50 and 200 mg/kg bw/d)	No data; read-across
Repeated dose toxicity dermal	Similar to OECD TG 411, rabbit, RL2, GLP	NOAEL(systemic) = 200 mg/kg bw/d (highest dose administred)	No data; read-across
Reproduction / Developmental Toxicity Screening Test	OECD TG 421, rat, RL1, GLP	NOAEL(parental)= 70 mg/kg bw/d; NOAEL(fertility females)= 70 mg/kg bw/d; NOAEL (fertility males) = 200 mg/kg bw/d; NOAEL(development)= 200 mg/kg bw/d	No data; read-across
Prenatal developmental toxicity	Similar to OECD TG 414, rabbit, RL2, GLP	NOAEL(development)= 200 mg/kg bw/d (highest dose administered)	No data; read-across

 

Table 4: Toxicological data for Amides, coco, N,N-bis(hydroxyethyl)

	Source substance		Target substance
Endpoint	Amides, coco, N,N-bis(hydroxyethyl)	Result	C16-18 DMAPA amidoamine
Acute toxicity dermal	Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics (FDA), RL2, pre-GLP	LD50(rabbit) > 2000 mg/kg bw	No data; read-across

 

For the target substance C16-18 DMAPA amidoamine an acute oral toxicity study according to OECD guideline 423, a dermal irritation study according to OECD Guideline 439 and a reverse gene mutation assay in bacteria according to OECD guideline 471 are available . As demonstrated above, the source substanceStearic acid 3-(dimethylaminopropyl)amide isthe main constituent of the target substance. The additional minor constituents with differing fatty acid chain lengths are not considered to influence the outcome of the toxicological studies what is demonstrated by similar results in the experimental studies (for further details please refer to the respective robust study summaries in IUCLID chapter 7.2.1).

For acute dermal toxicity, a read across to Amides, coco, N,N-bis(hydroxyethyl) is applied.This substance is structurally closely related toC16-18 DMAPA amidoamine and can be considered as a worst case due to more hydrophilic properties than C16-18 DMAPA amidoamine, which would favour dermal penetration.Thus, the read-across approach is considered to be valid.

 

5.2 Quality of the experimental data of the analogues:

Acute toxicity:

Reliable (RL1) GLP-compliant acute oral toxicity tests with the target substance C16-18 DMAPA amidoamine and the source substance Stearic acid 3-(dimethylaminopropyl)amide are available showing similar results.

For the assessment of acute dermal toxicity a pre-GLP test according to the Appraisal of the Safety of Chemicals in Foods, Drugs & Cosmetics with Amides, C8-18 and C18-unsatd., N,N-bis(hydroxyethyl) is available, which is considered to be reliable with restrictions (RL2).

The available data are sufficiently reliable and can be used in an analogue approach.

 

5.3 Classification and labelling

Concerning human health hazards, the source substance Stearic acid 3-(dimethylaminopropyl)amide is classified for irreversible effects on the eye (Eye Damage, Category 1, H318: Causes serious eye damage. / Xi; R41 Risk of serious damage to eyes). Based on the read-across, the target substance C16-18 DMAPA amidoamine will be classified accordingly.

 

6. Conclusion

The structural similarities between the source and the target substances and the similarities in their breakdown products presented above support the read-across hypothesis. Adequate and reliable scientific information indicates that the source and target substances and their subsequent degradation products have similar toxicity profiles.

The absence of acute toxicity of the source substance Stearic acid 3-(dimethylaminopropyl)amide is considered to be relevant also for the target substance C16-18 DMAPA amidoamine. No classification with respect to acute toxicity is required.

Justification for selection of acute toxicity – oral endpoint
OECD & EC guideline study, no deviations, GLP

Justification for selection of acute toxicity – inhalation endpoint
inhalation is not a relevant route of exposure

Justification for selection of acute toxicity – dermal endpoint
study according to Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics

Justification for classification or non-classification

Acute oral toxicity

Based on relevant, reliable and adequate data C16-18 DMAPA amidoamine does not need to be classified and labelled according to the CLP Regulation (EC) No 1272/2008 and Directive 67/548/EEC with respect to acute oral toxicity.

 

Acute dermal toxicity

Based on relevant, reliable and adequate data of read-across studies with a chemically related substance C16-18 DMAPA amidoamine does not need to be classified and labelled according to the CLP Regulation (EC) No 1272/2008 and Directive 67/548/EEC with respect to acute dermal toxicity.