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Description of key information

An acute oral toxicity study in the rat and an acute inhaltion toxicity study in the rat are available for the submission substance DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol)

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:
08-29 November 2017 (In-life)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Version / remarks:
17th December 2001
Deviations:
no
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
female
Details on test animals and environmental conditions:
Species and strain: Rat, Hsd: Sprague Dawley SD
Sex: Females (nulliparous and non-pregnant)
Age: 6-7 weeks old
Supplier: Envigo RMS s.r.l., San Pietro al Natisone (UD), Italy
Breeder: Envigo RMS B.V., Kreuzelweg 53, 5961 NM Horst, Netherlands
Date of arrival: 02 November 2017
Weight range at arrival: 157-164 g
Acclimatisation period: At least 5 days
Veterinary health check: During acclimatisation period
Animals per cage: 3 during the study; up to 5 during acclimatisation
Housing: Polisulfone solid bottomed cages measuring 59.5×38×20 cm, with nesting material provided into suitable bedding bags
Water: Drinking water supplied to each cage via a water bottle; Water supply ad libitum
Diet: 4 RF 18 diet supplied ad libitum throughout the study
Room lighting: Artificial (fluorescent tubes), daily light/dark cycle of 12/12 hours
Air changes: Approximately 15 to 20 air changes per hour
Temperature: Range 22 °C±2 °C
Relative humidity: Range 55%±15%
Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE: water (softened by reverse osmosis).
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10mL/kg bw
- Justification for choice of vehicle: based on solubility
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
Two groups of 3 females (4-hour fasted)
Control animals:
no
Details on study design:
A first group of 3 female animals of approximately 8 week of age, was dosed at a level of 2000 mg/kg bw (Step 1). Mortality did not occur. A second group, similarly composed, was then dosed at the same dose level (Step 2). No mortality occurred. No further doses were investigated since the objective of the study had been achieved.
Statistics:
Not required
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No deaths occurred in either group of three female rats.
Clinical signs:
In the first group of three rats, some clinical signs were observed in all animals on the day of dosing. Hunched posture and ataxia were recorded from 30 minutes after dosing up to 4 hours after dosing, piloerection from two hours up to 4 hours and decreased activity at two hours after dosing. In addition, one animal showed rales at 30 minutes after dosing. This sign recovered at two hours after dosing.

In the second group of three rats, Decreased activity was recorded in all animals from 30 minutes up to 4 hours after dosing, ataxia from 30 minutes up to two hours after dosing, hunched posture and piloerection at 4 hours after dosing. These signs had resolved by Day 2 of the study.
Body weight:
Changes in bodyweight observed during the study were within the expected range for this strain and age of animals, based on historical data.
Gross pathology:
No abnormalities were observed at necropsy.

Summary of findings

Group

Rats

Mortality

1

3 female

0/3

2

3 female

0/3

Interpretation of results:
Category 5 based on GHS criteria
Conclusions:
No mortality occurred in the six animals following dosing at 2000 mg/kg bw. Decreased activity, ataxia, hunched posture and piloerection were observed in all animals on the day of dosing but had resolved by Day 2 of the study. The acute toxicity estimate (ATE) is therefore >2000 mg/kg bw. No classification is required for acute toxicity according to CLP criteria.
Executive summary:

The acute toxicity of DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol) was investigated following a single oral administration to the Sprague Dawley rat followed by a 14-day observation period. A first group of three female rats was initially dosed at 2000 mg/kg bw (Step 1). No mortality occurred. Some clinical signs were observed in all animals on the day of dosing: hunched posture and ataxia were recorded from 30 minutes after dosing up to 4 hours after dosing, piloerection from two hours up to 4 hours and decreased activity at two hours after dosing. In addition, one animal showed rales at 30 minutes after dosing. A second group of three female rats was dosed at the same dose level (Step 2). No mortality occurred. Decreased activity was recorded in all animals from 30 minutes up to 4 hours after dosing, ataxia from 30 minutes up to two hours after dosing, hunched posture and piloerection at 4 hours after dosing. Bodyweight changes recorded during the study were within the expected range for this strain and age of animals. Gross necropsy did not reveal any effects of treatment. The acute oral LD50 of DMP Tech. was therefore found to the >2000 mg/kg bw under the conditions of this study.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw
Quality of whole database:
A modern, GLP- and Guideline-compliant study is available for the submission substance DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol)

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
06 April - 24 April 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 433 draft (Acute Inhalation Toxicity: Fixed Concentration Procedure) (not officially approved)
Version / remarks:
9 October 2017
Deviations:
no
GLP compliance:
yes
Test type:
fixed concentration procedure
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Envigo RMS Spain
- Age at study initiation: 10 weeks
- Fasting period before study: Not applicable
- Housing: Group housing except during exposure
- Diet: ad libitum) except during exposure
- Water: except during exposure
- Acclimation period: 19 days; rats were also acclimated to the restraining tubes for 30 minutes

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.1-25.6
- Humidity (%): 29-50
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 09 April 2018 To: 23 April 2018
Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
2.25 µm
Geometric standard deviation (GSD):
> 1.88 - < 2.12
Remark on MMAD/GSD:
MMAD was measured at two sampling points during the study and gave values of 2.10 µm (GSD 1.88) and 2.40 µm (GSD (2.12). The proportion of respirable particles (<4 µm) was calculated to be 87.10 and 77.91% respectively.
Details on inhalation exposure:
Inhalation exposure was performed using a flow-past, nose-only exposure system. The animals were confined separately in restraint tubes which were positioned radially around the exposure chamber. The exposure system ensured a uniform distribution and provided a constant flow of test material to each exposure tube. The mean flow of air at each tube was approximately 1.137 L/min, which was sufficient to minimize rebreathing of the test aerosol. Exposure chambers type EC-FPC-232 (anodised aluminium, volume inside compartment: approximately 3 L), equipped with glass exposure tubes were used. The rats were individually exposed in glass tubes matching their size. Before treatment started, the homogeneity for the different levels of the exposure chamber was confirmed. The temperature and relative humidity of the test atmosphere in the exposure chamber were maintained as required by experimental conditions. Air flow was monitored regularly.

A liquid aerosol was generated from the test material using a nebulizer. The aerosol was diluted with filtered air from a compressor and conveyed via glass tubing, from the generator to the exposure chamber. The flow rate through the exposure chamber was adjusted as necessary. The test material usage was determined during exposure by weighing before and after exposure to determine the quantity used. The weight used was then divided by the total air-flow volume to give the nominal concentration. These data were used for the purpose of monitoring the performance of the generation system. Gravimetric determination of the aerosol concentration was performed twice each hour of exposure. Aerosol samples were collected using a filter sampling device for a sampling duration of 10 minutes. The filters were weighed before and immediately after sampling using a calibrated balance. The gravimetric aerosol concentration was calculated from the amount of test material present on the filter and the sample volume. The particle size distribution was determined gravimetrically twice during exposure; cumulative particle size distribution of the test aerosol was determined using a cascade impactor. The particle size distribution of the test material in the generated aerosol was measured by gravimetry analyzing the test item deposited on each stage of the cascade impactor. The mass median aerodynamic diameter (MMAD) and the geometric standard deviation (GSD) were calculated on the basis of the results from the impactor.

Temperature in the chamber was measured continuously during exposure; the target range was 19-25 ºC. The results were reported approximately hourly from the start of the inhalation exposure. Relative humidity in the chamber was measured continuously during exposure. The results were reported approximately hourly from the start of the inhalation exposure. The oxygen and CO2 concentration of the test atmosphere were measured during the exposure period using a portable gas detector. These concentrations were maintained above 19% and below 1% respectively. The results were reported approximately hourly from the start of the inhalation exposure. The exposure airflow rate was adjusted as appropriate before the start of the exposure using the pressure difference over a Venturi tube. The actual airflow rate was monitored at least hourly during exposure. The target range was 1.0 ± 0.5 L/min through each inhalation tube.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Remarks on duration:
4 hour (nose-only); standard expsosure conditions
Concentrations:
4.701 mg/L
No. of animals per sex per dose:
Five males
Control animals:
no
Preliminary study:
Not relevant.
Key result
Sex:
male
Dose descriptor:
LC50
Effect level:
> 4.701 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
not determinable due to absence of adverse toxic effects
Mortality:
No deaths occurred, either during the 4-hour exposure period or during the 14-day observation period.
Clinical signs:
other: Immediately after exposure, wet fur, chromorrhinorrhoea and/or chromodacryorrhoea were observed in all animals. These transient signs were considered to be related to the exposure procedure rather than to a direct effect of the test material. All signs
Body weight:
A decrease in mean bodyweight of approximately 5% was observed in all animals between Day 1-2. Bodyweight increased thereafter and had recoverd by Day 8. Total mean body weight gain of approximately 10% was recorded during the 14 day observation period (from Day 1-15).
Gross pathology:
No macroscopic findings were present in any of the animals at necropsy.
Other findings:
None.

Summary of findings

Exposed (#)

Mortality (#)

Clinical signs (#)

Bodyweight (g)

Day 1

Day 2

Day 8

Day 15

5

0/5

5/5

317.3

302.7

325.9

348.6

Exposure data

Analytical concentration (mg/L)

MMAD (µm)

GSD

% particles <4 µm

4.701

2.10, 2.40

(mean 2.25)

1.88, 2.12

87.10, 77.91

(mean 82.51)

Interpretation of results:
Category 5 based on GHS criteria
Conclusions:
The acute (4 -hour, nose-only) inhalation LC50 of DMP Tech was found to be >4.701 mg/L under the conditions of this study. In the absence of any mortality at this concentration, it can reliably be predicted that the LC50 will be >5 mg/L. DMP Tech does not therefore require classification for acute inhalation toxicity according to CLP criteria.
Executive summary:

The acute inhalation toxicity of DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol) was investigated in a Fixed Concentration Procedure study performed according to OECD 433. A single group of five male Sprague-Dawley rats was exposed for four hours (nose-only) to an atmosphere containing liquid aerosols of DMP Tech. at a gravimetric concentration of 4.701 mg/L and observed for 14 days. No deaths occurred, either during the 4-hour exposure period or during the 14-day observation period. Immediately after exposure, wet fur, chromorrhinorrhoea and/or chromodacryorrhoea were observed in all animals.  These transient signs were considered to be related to the exposure procedure rather than to a direct effect of the test material.  All signs had resolved by one hour after exposure.  From Day 2 (24 hours after exposure) until sacrifice at Day 15, no clinical signs were recorded in any animals and all of them exhibited normal behaviour. A decrease in mean bodyweight of approximately 5% was observed in all animals between Day 1-2.  Bodyweight increased thereafter and had recoverd by Day 8.  Total mean body weight gain of approximately 10% was recorded during the 14 day observation period (from Day 1-15). No macroscopic findings were present in any of the animals at necropsy. The acute (4 -hour, nose-only) inhalation LC50 of DMP Tech was found to be >4.701 mg/L under the conditions of this study.  DMP Tech does not therefore require classification for acute inhalation toxicity according to CLP criteria.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC50
Value:
4 701 mg/m³
Quality of whole database:
A modern, GLP- and Guideline-compliant study is available for the submission substance DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol)

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Acute oral toxicity

The acute toxicity of DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol) was investigated following a single oral administration to the Sprague Dawley rat followed by a 14-day observation period. A first group of three female rats was initially dosed at 2000 mg/kg bw (Step 1). No mortality occurred. Some clinical signs were observed in all animals on the day of dosing: hunched posture and ataxia were recorded from 30 minutes after dosing up to 4 hours after dosing, piloerection from two hours up to 4 hours and decreased activity at two hours after dosing. In addition, one animal showed rales at 30 minutes after dosing. A second group of three female rats was dosed at the same dose level (Step 2). No mortality occurred. Decreased activity was recorded in all animals from 30 minutes up to 4 hours after dosing, ataxia from 30 minutes up to two hours after dosing, hunched posture and piloerection at 4 hours after dosing. Bodyweight changes recorded during the study were within the expected range for this strain and age of animals. Gross necropsy did not reveal any effects of treatment. The acute oral LD50 of DMP Tech. was therefore found to the >2000 mg/kg bw under the conditions of this study.

Acute dermal toxicity

No testing is required; DMP Tech can b predicted to be of low acute dermal toxicity on the basis of its low acute oral toxicity.

Acute inhalation toxicity

The acute inhalation toxicity of DMP Tech. was investigated in a Fixed Concentration Procedure study performed according to OECD 433. A single group of five male Sprague-Dawley rats was exposed for four hours (nose-only) to an atmosphere containing liquid aerosols of DMP Tech. at a gravimetric concentration of 4.701 mg/L and observed for 14 days. No deaths occurred, either during the 4-hour exposure period or during the 14-day observation period. Immediately after exposure, wet fur, chromorrhinorrhoea and/or chromodacryorrhoea were observed in all animals.  These transient signs were considered to be related to the exposure procedure rather than to a direct effect of the test material.  All signs had resolved by one hour after exposure.  From Day 2 (24 hours after exposure) until sacrifice at Day 15, no clinical signs were recorded in any animals and all of them exhibited normal behaviour. A decrease in mean bodyweight of approximately 5% was observed in all animals between Day 1-2.  Bodyweight increased thereafter and had recoverd by Day 8.  Total mean body weight gain of approximately 10% was recorded during the 14 day observation period (from Day 1-15). No macroscopic findings were present in any of the animals at necropsy. The acute (4 -hour, nose-only) inhalation LC50 of DMP Tech was found to be >4.701 mg/L under the conditions of this study.  DMP Tech does not therefore require classification for acute inhalation toxicity according to CLP criteria.

Justification for classification or non-classification

Based on the results of the acute oral toxicity study, DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol) does not require classification for acute oral toxicity according to CLP criteria. This study reports an LD50 of >2000 mg/kg bw.

Based on the results of the acute inhalation toxicity study, DMP Tech. (reaction mass of 2-ethyl-2 -(methoxymethyl)-propane-1,3-diol and 2 -ethylpropane-1,3 -diol) does not require classification for acute oral toxicity according to CLP criteria. This study reports an LC50 of >4.701 mg/L. In the absence of any mortality at this concentration, it can reliably be predicted that the LC50 will be >5 mg/L.