Reaction mass of N-(2-hydroxyethyl)alkyl] alkylamide and glycerol

Endpoint summary

Description of key information

A complete lack of cytotoxicity in various in-vitro studies can be interpreted as indicating a likely oral LD50 value > 2000 mg/kg bodyweight. QSAR data indicating low acute oral toxicity with LD50 > 5000 mg/kg bw.

Acute dermal toxicity testing in rats showed no effects at 2000 mg/kg bw.

There are no signs of phototoxic effects on BALB/c 3T3 cells Neutral Red Test during Simultaneous Irradiation with Artificial Sunlight.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Study period:

9th November 2015

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Principles of method if other than guideline:

Background
Methods
i. Profiling - OECD QSAR Toolbox (v3.3)
ii. DEREK NEXUS (v.4.1.0)
iii. VegaNIC (v.1.1.1)
iv. TOPKAT (Discovery Studio client 3.1)
v. ACD/ToxSuite 2.95
vi. ECOSAR (v.1.11)

GLP compliance:

no

Test type:

other: QSAR

Specific details on test material used for the study:

DGA-Acetamide; CAS: 118974-46-2
N-[2-(2-hydroxyethyl)ethyl]acteamide [IUPAC]
Structure: CC(=O)NCCOCCO

Species:

rat

Details on test animals or test system and environmental conditions:

As data is based on QSAR analysis, strain and sex, as well as environmental conditions are are not specified.

Route of administration:

oral: gavage

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

>= 5 000 mg/kg bw

Based on:

other: This is based on consistent results of QSAR models,

Remarks on result:

other: based on QSAR model predictions

Profiling

The various Reactivity profiles in QSAR Toolbox basically show little or no concerns. The only concerns reported are “in vivo mutagenicity (Micronucleus) alerts by ISS” based on “H-acceptor-path3-H-acceptor”. This involves the presence oftwo bonded atoms connecting two H-bond acceptors in the structure, which is rather unspecific. (Most of the l substances showing this alert have negative in vitro mammalian cell micronucleus test results).

There is one additional repeated dose toxicity alert from HESS for renal toxicity. This is based on the structural similarity to Diethylene glycol, which has is known to cause nephrotoxicity. (Dice, atom centered fragment indicate a 58.85% similarity between DGA and Diethylene glycol).

Metabolism of DGA is not expected to occur in large extend. The substance is expected to be poorly absorbed from skin, and relatively rapidly excreted via urine.

On overall, the available information does not support a concern for the formation of Acetamide from DGA-Acetamide. All available reported examples of N-Dealkylation from the aldehyde involve tertiary amine structures, and de-alkylation of (very) short alkyl groups from the amine, and involve structures that involve lipophilic parts, generally aromatic rings. The DGA-Acetamide structure however involves a secondary amine that is negatively linked to this metabolic reaction, a diethylene glycol part rather than a short alkyl chain, and no aromatic or cyclic part.

Hydrolysis by hydrolase activity on the other hand is a commonly observed reaction for amide structures as found in DGA-Acetamide. Actual rate is uncertain, but for metabolic route it is considered more likely.

DEREK:

According to DEREK the structure does not contain specific hazardous elements. More specifically, both genotoxicity and sensitization are predicted to be negative. Based on the di-ethylene glycol moiety in the structures, an alert is fired for possible bone marrow toxicity and nephrotoxicity. Further, ‘Nothing else to report’.

VEGA

VEGA models in general predict low concerns for hazards.

TOPKAT

On overall the TOPKAT models predict DGA to be of low toxicity. Of the many models on carcinogenicity, there is only one resulting to a positive outcome (FDA mouse male), whereas all others are negative. The overall WoE rodent carcinogenetic model predicts ‘Non-Carcinogen’. Other toxicity models show a low toxicity potential. The only hazard predicted is a moderate eye irritation.

ACD/ToxSuite

ACD/ToxSuite also predicts low toxicity. The only potential hazard indicated are possible skin and eye irritation. This is on the basis of comparison to Aliphatic monohydroxy alcohols, that in majority are irritant to skin and eye

ECOSAR

ECOSAR predicts low aquatic toxicity for DGA, based on evaluations both for the QSAR substance categories ‘Amides’ and ‘Neutral organics’.

Interpretation of results:

GHS criteria not met

Conclusions:

QSARs predict an acute LD50 > 5000 mg/kg bw

Executive summary:

Results from molecular profiling indicate high water solubility, low logPow and reasonable uptake by oral route and probably very limited uptake via dermal route (dermalpenetration coefficientis lower than that of water).

The predicted transformation/metabolism possibilities by QSAR Toolbox (v 4.3) do not list substances of specific concern (specifically not acetamide) among the likely metabolites: Hydrolysis simulation indicate possible split into acetic acid and diglycolamine, or even ethanediol and n-2-hydroxyethylacetamide, but not Acetamide.

On overall, the profiling and QSAR results indicate no interaction to DNA or protein binding, no mutagenicity, no carcinogenicity and a general low toxicity. Only (moderate) ocular irritation has been predicted, although results from available BCOP study indicates a lack of irritating potential.

All in all, a low toxicity profile is indicated for the structure.

The QSAR data for acute (oral) toxicity was assessed in TOPKAT (DiscoveryStudio 2019, Toxicity Prediction) and ACD/ToxSuite (Tox Boxes v 2.9).

TOPKAT models indicate low acute toxicity by both oral and inhalation route in the rat: Oral LD50 rat 5399 mg/kg bw, and Inhalational LC50 in rat is predicted at 5270 mg/m3/h.

ACD/ToxSuite model predicted comparable low toxicity, with a rat oral LD50 value most likely to exceed 5000 mg/kg, and predicts an acute toxicology classification Cat 5 or non-toxic LD50 >2000mg/kg with a high probability score of 0.908.

Based on this information acute oral toxicity testing has not been done.  This has also taken into consideration that this substance is sold as a cosmetic ingredient.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

All information from profiling, QSARs and performed in vitro studies consistently point at low toxicity. The data from QSARs are reported with relative high validity.

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:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

2017

Deviations:

no

GLP compliance:

yes

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Species: Rat
Strain: Crl: WI(Han)
Condition: Outbred, SPF-Quality
Source: Charles River Deutschland, Sulzfeld, Germany
Number of Animals: 3 females (nulliparous and non-pregnant).
Age at the Initiation of Dosing: Young adult animals (approximately 10-12 weeks old) were selected.
Weight at the Initiation of Dosing: 194 to 230 g.

following assignment to the study, animals were individually housed in polycarbonate cages (Makrolon MIII type; height 18 cm.) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) equipped with water bottles.

Target temperatures of 18 to 24°C with a relative target humidity of 40 to 70% were maintained. The actual daily mean temperature during the study period was 21°C with an actual daily mean relative humidity of 37 to 59% (see deviations in Appendix 3). A 12-hour light/12-hour dark cycle was maintained. Ten or greater air changes per hour with 100% fresh air (no air recirculation) were maintained in the animal rooms.

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- One day before dosing, an area of approximately 5x7 cm on the back of the animals was clipped.
- Area of exposure: 10% of the total body surface, i.e. approximately 18 cm² for females
- Type of wrap if used: The test item was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D), successively covered with Coban elastic bandage. A piece of Micropore tape was additionally used for fixation of the bandages

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the dressing was removed and the skin cleaned of residual test item using water.
- Time after start of exposure: 24 hours after application

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg. The dose volume for each animal was based on the body weight measurement prior to dosing. Dose volume (mL/kg body weight) was calculated as follows: Dose level (g/kg) / spec.gravity or density (g/mL).
- Concentration (if solution): pure, no vehicle
- Constant volume or concentration used: Only one dose group of 2000 mg/kg bw

No vehicle; test item administered as received.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality: twice daily; Postdose observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter. Body weight on Day 1 (predose), 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed: local effects and irritation, clinical signs, body weight, and examination for internal macroscopic abnormalities.

Key result

Sex:

female

Dose descriptor:

LDLo

Effect level:

>= 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

not determinable due to absence of adverse toxic effects

Remarks:

No toxicity, and no irritation; Only observed effects include chromodacryorrhoea (snout) noted for two animals on Day 1 only.

Mortality:

No mortality

Clinical signs:

Chromodacryorrhoea (snout) was noted for two animals on Day 1.

Body weight:

No effects

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Other findings:

No irritation was noted for any of the animals at any time point.

Interpretation of results:

GHS criteria not met

Conclusions:

The dermal LD50 value in Wistar Han rats was established to exceed 2000 mg/kg body weight.

Executive summary:

The objective of this study was to determine the potential toxicity of Reaction mass of N-[2 -(2hydroxyethoxy) ethylacetamide and Glycerol, when given by a single dermal dose.  

The study was carried out based on the guidelines described in OECD No. 402 (2017) "Acute Dermal Toxicity"

Initially, Reaction mass of N-[2-(2hydroxyethoxy) ethylacetamide and Glycerol was administered to a single female Wistar Han rat by a single dermal application at 2000 mg/kg body weight for 24 hours in a range finder study.  Based on the results, the main study was performed by dosing two additional females at 2000 mg/kg.  All animals were subjected to daily observations and weekly determination of body weight.  Macroscopic examination was performed on the day of death or after terminal sacrifice (Day 15). Results for the main study include the results for the animal dosed at 2000 mg/kg in the range finder study.  

Results: No mortality occurred. No irritation was noted for any of the animals at any time point. Chromodacryorrhoea (snout) was noted for two animals on Day 1. The body weight gain shown by the animals during the observation period was within the range expected for rats used in this type of study. No abnormalities were found at macroscopic post mortem examination of the animals.

The dermal LD50 value of Reaction mass of N-[2-(2hydroxyethoxy) ethylacetamide and Glycerol in Wistar Han rats was established to exceed 2000 mg/kg body weight.  

Based on these results, Reaction mass of N-[2-(2hydroxyethoxy) ethylacetamide and Glycerol does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2017) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

There is no toxicity hazard information available on the substance. Results from molecular profiling indicate high water solubility, low logPow and reasonable uptake by oral route and probably very limited uptake via dermal route (dermal penetration coefficient lower than water). All in all, a low toxicity profile is indicated for the structure.

The profiling and QSAR results indicate no interaction to DNA or protein binding, no mutagenicity, no carcinogenicity and a general low toxicity. Only (moderate) ocular irritation has been predicted, although results from available BCOP study indicates a lack of irritating potential.

Acute oral toxicity:

The QSAR data for acute (oral) toxicity was assessed in TOPKAT (DiscoveryStudio 2019, Toxicity Prediction) and ACD/ToxSuite (Tox Boxes v 2.9).

TOPKAT models indicate low acute toxicity by both oral and inhalation route in the rat: Oral LD50 rat 5399 mg/kg bw, and Inhalational LC50 in rat is predicted at 5270 mg/m3/h.

ACD/ToxSuite model predicted comparable low toxicity, with a rat oral LD50 value most likely to exceed 5000 mg/kg, and predicts an acute toxicology classification Cat 5 or non-toxic with a high probability score of 0.908.

In addition, no cytotoxicity is observed at highest concentration of 10 mM after 4 hr or 24 h in in-vitro genotoxicity studies with either Human lymphocytes (OECD 487) and mouse lymphoma cells (OECD 490), and also a cytotoxicity assay in vitro with BALB/c 3T3 Cells: Neutral Red (NR) Test (OECD 432)during Simultaneous Irradiation with Artificial Sunlight, showed no cytotoxicity up to the highest tested concentration of 1000 µg/mL.  Finally, in hCLAT assay, even 5000 µg/mL was without cytotoxicity to the human monocytic cell line THP-1.

A complete lack of cytotoxicity can be interpreted as indicating a likely oral LD50 value >2000 mg/kg bodyweight. 

 

Acute dermal toxicity:

Subsequent to registration requirements in another country, an acute dermal toxicity has been performed in rats as limit dose (OECD 401).  This study resulted to a LD50 > 2000 mg/kg bw. No toxicity and no irritation was observed in the animals dosed at 2000 mg/kg bw.

 

Acute inhalation toxicity:

There is no study on inhalation toxicity available.

REACH stipulates that testing by the inhalation route is appropriate if exposure of humans via inhalation is likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size. REACH guidance R.7.a, chapter. 7.4 Acute toxicity indicates that in principle no inhalation studies are needed when vp < 0.1 Pa at 20°C or particle size > 100 µm.Reaction mass of N-[2-(2-hydroxyethoxy)ethyl]acetamide and glycerolhas a measured vapour pressure of 0.028 Pa at 25 °C and high boiling point of 332°C, indicating very low volatility. Its use is limited to cosmetic skin care products and does not involve the forming of dusts or aerosols, particles or droplets of an inhalable size. So, exposure to humans via the inhalation route will be unlikely to occur.

 

Substance has no surface-active properties. There are no specific concerns for hazard from aspiration.

Additional information:

The substance did not have any phototoxic effects on BALB/c 3T3 cells, and showed no cytotoxicity up to the highest tested concentration of 1000 µg/mL.

Justification for classification or non-classification

The substance is of low acute toxicity. The substance shows no cytotoxicity and QSARs predict low acute oral toxicity with LD50 > 5000 mg/kg bw.

Acute toxicity by dermal route showed no toxicity at 2000 mg/kg bw.

Related very to low vp and expected lack of exposures from dusts or aerosols, there is low likelihood of relevant exposures via inhalation. There are no specific concerns for hazard from aspiration.

The active substance is not structurally related to any known class of neurotoxic chemicals indicative for STOT-SE Cat.3 for narcosis effects.

The available information indicates that no classification is needed.