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Diss Factsheets

Administrative data

Description of key information

DHX2 was tested in rats in an acute oral toxicity study performed according to OECD 423 test guideline, in an acute dermal toxicity study performed according to OECD 402 guideline and in an acute inhalation toxicity study performed according to OECD 403 guideline.

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:
August 20, 2004 - September 07, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Version / remarks:
(2001)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Version / remarks:
(1996)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
Version / remarks:
(2002)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nousan, Notification No 8147, November 2000, including the most recent partial revisions.
Deviations:
no
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals or test system and environmental conditions:
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Young adult animals (approx. 8-9 weeks old)
- Weight at study initiation: Body weight variation was within +/- 20% of the sex mean.
- Fasting period before study: Food was withheld overnight (for a maximum of 20 hours) prior to dosing until 3-4 hours after administration of the test substance.
- Housing: Group housing of 3 animals per cage in labeled Macrolon cages
- Diet: Free access to to standard pelleted laboratory animal diet (from Altromin (code VRF 1), Lage, Germany).
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.1 – 23.5
- Humidity (%): 40 - 77
- Air changes (per hr): approx 15
- Photoperiod (hrs dark / hrs light): 12/12

Cleaning procedures in the room might have caused the temporary fluctuations above the optimal maximum level of 70% for relative humidity. Based on laboratory historical data, these fluctuations were considered not to have affected the study integrity.
Route of administration:
oral: gavage
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
GAVAGE METHOD: stainless steel stomach tube.

Frequency: single dosage, on Day 1.

MAXIMUM DOSE VOLUME APPLIED: 2000 mg/kg (1.754 ml/kg) body weight. Dose volume calculated as dose level : density.

DOSAGE PREPARATION: The test substance was dosed undiluted as delivered by the sponsor.

Doses:
2000 mg/kg body weight
No. of animals per sex per dose:
6 (2 groups of three females in a stepwise manner)
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality/Viability: Twice daily.
Body weights: Days 1 (pre-administration), 8 and 15.
Clinical signs: At periodic intervals on the day of dosing (Day 1) and once daily thereafter, until Day 15.
- Necropsy of survivors performed: All animals were sacrificed and subjected to necropsy. Descriptions of all internal macroscopic abnormalities were recorded.
- Other examinations performed: none.
Statistics:
No statistical analysis was performed (The method used is not intended to allow the calculation of a precise LD50 value).
Sex:
female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No mortality occurred.
Clinical signs:
other: Hunched posture and /or piloerection were noted among the animals on days 1 and/or 2. One animal showed alopecia on the tail base between days 4 and 9. Alopecia is commonly seen in group housed rats and therefore no toxicological significance was attache
Gross pathology:
No abnormalities were found at macroscopic post mortem examination of the animals.
Interpretation of results:
GHS criteria not met
Conclusions:
In an acute oral toxicity study with rats, performed according to OECD/EC test guidelines, an LD50 >2000 mg/kg bw was determined.
Executive summary:

DHX2 was administered by oral gavage in six female Wistar rats according to OECD 423 guideline and GLP principles.

No mortality occurred. Hunched posture and /or piloerection were noted among the animals on days 1 and/or 2.

No effect on body weight gain was noted. No abnormalities were found at macroscopic post mortem examination of the animals.

The oral LD50 value of DHX2 in female rats was established as exceeding 2000 mg/kg body weight.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The study has a Klimisch score of 1.

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:
June 04 - June 19, 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study has been performed according to OECD guideline 403 and GLP principles.
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Version / remarks:
(1981 and draft document 1996)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Version / remarks:
(1992)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1300 (Acute inhalation toxicity)
Version / remarks:
(1998)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Japanes Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nousan, Notification No 8147, November 2000, including the most recent partial revisions
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: young adult animals (13 weeks old)
- Weight at study initiation: +/- 20% of sex mean
- Housing: group housing (5/cage) in labelled Macrolon cages containing sterilised sawdust as bedding material and paper as cage-enrichment
- Diet: free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany) except during exposure to the test substance
- Water: free access to tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.3-21.4
- Humidity (%): 41-78
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: 4-19 June 2008
Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
air
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The chamber consisted of 3 animal sections with 8 animal ports each. The inlet of the test atmosphere was located in the top section and the outlet was located in the bottom section.
- Exposure chamber volume: not indicated
- Method of holding animals in test chamber: restraining tube
- Source and rate of air: pressurized air; 2.0 L/min
- System of generating aerosols: generated by two nebulizers (type 950, Hospitak Inc. Lindenhurst, NY, USA)
- Method of particle size determination: gravimetrically, samples collected with an 8-stage Marple personal cascade impactor fiber glass filters (FG-033450-GA, AE Fiber glass, SKC Omega Specialty Division, Chelmsford, MA, USA) and a fiber glass back-up filter (SEC-290-F1, Westech, Upper Stondon, Bedfordshire, England)
- Treatment of exhaust air: passed through a filter to determine the nominal concentration
- Temperature, humidity, pressure in air chamber: 21.0-21.4 °C; relative humidity was not measured; pressure was not reported

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetrical analysis: Samples were drawn through a glass fiber filter (type APFC04700, Millipore, Billerica, MA, USA). The filters were dried in a kiln for 5 minutes before weighing to allow the volatile part of the test substance to evaporate. The collected amount of the non-volatile part of the test substance in the air sample was measured gravimetrically. Sample volumes were measured by means of a dry gas meter (type G 1.6, Actaris Meterfabriek B.V., Dordrecht, The Netherlands).
- Samples taken from breathing zone: yes, from one of the free animal ports

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: determined twice
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 1.7 µm/1.9 at both occasions

Analytical verification of test atmosphere concentrations:
yes
Remarks:
gravimetrically, 8 times 3L sample during exposure
Duration of exposure:
4 h
Concentrations:
nominal 14.1 mg/L; actual 5.2 +/- 0.3 mg/L
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: during exposure, 3 times for mortality, behavioural signs of distress and effects on respiration; twice daily for mortality/viability; twice on the day of dosing and once daily thereafter for clinical signs; days 1 (pre-administration), 8 and 15 for body weights
- Necropsy of survivors performed: yes
Statistics:
None
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.2 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Mortality:
No mortality occurred.
Clinical signs:
other: During exposure irregular breathing was noted in all animals at 1 hour after initiation of exposure. No symptoms were noted at 2 and 3 hours after initiation of the exposure. After exposure, between Days 1 and 5, chromodacryorrhoea on the snout, hunched p
Body weight:
During the first week after exposure the animals showed body weight loss or reduced body weight gain, The body weight gain during the second week after exposure shown by the animals was considered to be similar to that expected of normal untreated animals of the same age and strain.
Gross pathology:
No abnormalities were found at macroscopic post mortem examination of the animals.
Interpretation of results:
GHS criteria not met
Conclusions:
The inhalatory LC50, 4h value of DHX2 in Wistar rats was established to exceed 5 mg/L.
Executive summary:

Rats (5/sex) were exposed to 5.2 mg/L of the test substance by inhalation according to OECD 403 and GLP principles.

No mortality occurred. During exposure irregular breathing was noted in all animals. Day 1 to 5 after exposure chromodacryorrhoea on the snout, hunched posture, laboured respiration, lethargy and rales were noted in the majority of the animals and piloerection in females. Body weight loss/reduced body weight gain was seen during the first week of exposure only. No abnormalities were found at macroscopic examination.

The inhalation LC50 (4 -hours) of the test substance in rats was established to exceed 5.2 mg/L.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The study has a Klimisch score of 1.

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
Study period:
August 25, 2004 - September 08, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Version / remarks:
(1987)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Version / remarks:
(1992)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1200 (Acute Dermal Toxicity)
Version / remarks:
(1998)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nousan, Notification No 8147, November 2000; including the most recent partial revisions.
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
other: Wistar strain, Crl:(WI) BR
Sex:
male/female
Details on test animals or test system and environmental conditions:
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Young adult animals (approx. 8 weeks old)
- Weight at study initiation: Body weight variation was within +/- 20% of the sex mean.
- Housing: Individually housed in labelled Macrolon cages
- Diet: Free access to standard pelleted laboratory animal diet (from Altromin (code VRF 1), Lage, Germany).
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.1 – 23.5
- Humidity (%): 41 - 74
- Air changes (per hr): approx 15
- Photoperiod (hrs dark / hrs light): 12/12

Cleaning procedures in the room might have caused the temporary fluctuations above the optimal maximum level of 70% for relative humidity. Based on laboratory historical data, these fluctuations were considered not to have affected the study integrity.
Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
One day before exposure (Day -1) an area of approximately 5x7 cm on the back of the animal was clipped.

The test substance was applied in an area of approx. 10% of the total body surface, i.e. approx. 25 cm² for males and 18 cm² for females. The test substance was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D), successively covered with aluminium foil and Coban elastic bandage. A piece of Micropore tape was additionally used for fixation of the bandages in females only.

Frequency: Single dosage, on Day 1.

Washing: Following application, dressings were removed and the skin cleaned of residual test substance using water.
Duration of exposure:
24 hours.
Doses:
2000 mg/kg

No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
Dose volume: (1.754 ml/kg) body weight. Dose volume calculated as follows: dose level : density.

DOSAGE PREPARATION: The test substance was dosed undiluted as delivered by the sponsor.

Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality/Viability: Twice daily.
Body weights: Days 1 (pre-administration), 8 and 15 and at death (if found dead after day 1).
Clinical signs: At periodic intervals on the day of dosing (day 1) and once daily thereafter, until day 15.
- Necropsy of survivors performed: All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities recorded.
Statistics:
None.
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
One male was found dead on day 1.
Clinical signs:
other: Hunched or flat posture, chromodacryorrhoea, diarrhoea and/or hypothermia were noted among all animals on days 1 and/or 2. General or maculate erythema, scales and/or scabs were seen in the treated skin-area of all animals during the observation period.
Gross pathology:
Isolated gray-white foci on the liver and enlargement of the liver were noted in the animal found dead on day 1. Macroscopic post mortem examination of the other animals did not reveal any abnormalities.
Interpretation of results:
GHS criteria not met
Conclusions:
In an acute dermal toxicity study with rats, performed according to OECD/EC test guidelines, an LD50 >2000 mg/kg bw was determined.
Executive summary:

DHX2 was administered to five Wistar rats of each sex by a single dermal occlusive application at 2000 mg/kg bw according to OECD 402 guideline and GLP principles.

One male was found dead on day 1. Hunched or flat posture, chromodacryorrhoea, diarrhoea and/or hypothermia were noted among all animals on days 1 and/or 2. General or maculate erythema, scales and/or scabs were seen in the treated skin-area of all animals during the observation period. No body weight gain effects were observed. Isolated gray-white foci on the liver and enlargement of the liver were noted in the animal found dead on day 1. Macroscopic post mortem examination of the surviving animals did not reveal any abnormalities.

The dermal LD50value of DHX2 in Wistar rats was established to exceed 2000 mg/kg body weight.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The study has a Klimisch score of 1.

Additional information

Acute oral:

DHX2 was administered by oral gavage in six female Wistar rats according to OECD 423 guideline and GLP principles.

No mortality occurred. Hunched posture and /or piloerection were noted among the animals on days 1 and/or 2.

No effect on body weight gain was noted. No abnormalities were found at macroscopic post mortem examination of the animals.

The oral LD50 value of DHX2 in female rats was established as exceeding 2000 mg/kg body weight.

Acute inhalation:

Rats (5/sex) were exposed to 5.2 mg/L of the test substance by inhalation according to OECD 403 and GLP principles.

No mortality occurred. During exposure irregular breathing was noted in all animals. Day 1 to 5 after exposure chromodacryorrhoea on the snout, hunched posture, laboured respiration, lethargy and rales were noted in the majority of the animals and piloerection in females. Body weight loss/reduced body weight gain was seen during the first week of exposure only. No abnormalities were found at macroscopic examination.

The inhalation LC50 (4 -hours) of the test substance in rats was established to exceed 5.2 mg/L.

Acute dermal:

DHX2 was administered to five Wistar rats of each sex by a single dermal occlusive application at 2000 mg/kg bw according to OECD 402 guideline and GLP principles.

One male was found dead on day 1. Hunched or flat posture, chromodacryorrhoea, diarrhoea and/or hypothermia were noted among all animals on days 1 and/or 2. General or maculate erythema, scales and/or scabs were seen in the treated skin-area of all animals during the observation period. No body weight gain effects were observed. Isolated gray-white foci on the liver and enlargement of the liver were noted in the animal found dead on day 1. Macroscopic post mortem examination of the surviving animals did not reveal any abnormalities.

The dermal LD50value of DHX2 in Wistar rats was established to exceed 2000 mg/kg body weight.


Justification for selection of acute toxicity – oral endpoint
One key study available.

Justification for selection of acute toxicity – inhalation endpoint
One key study available.

Justification for selection of acute toxicity – dermal endpoint
One key study available.

Justification for classification or non-classification

Based on the results it can be concluded that DHX2 does not need to be classified for acute oral, dermal or inhalation toxicity according to Regulation (EC) No 1272/2008.