Nitrile hydratase recombinant from E.coli

Endpoint summary

Description of key information

Acute toxicity: oral key study (Nakamura, 2004):

Under the conditions of this study, the test material was found to have a LD50 > 2000 mg/kg bw when it was administered orally to rats once.

Acute toxicity: inhalation and dermal

In accordance with Column 2 of REACH Annex VIII, acute toxicity need only be addressed in one route if there is only one route of human exposure that is likely. Information on the acute toxicity of the substance is provided for the oral route of exposure, since human exposure via the dermal and inhalation routes of exposure are not considered to be likely routes of human exposure. In vivo acute dermal and/or inhalation toxicity studies will not add any value and cannot be expected to provide valuable knowledge and are thus considered scientifically and ethically unjustified.

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:

20 November 2003 to 12 December 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Crj: CD(SD)

Remarks:

Crj:CD(SD)IGS strain

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 weeks
- Weight at study initiation: 167 - 179 kg at start of quarantine acclimation. body weight of each animal of each group was within ± 20% of the average body weight of all animals at the time of administration.
- Fasting period before study: 18 hours 30 minutes to 19 hours 30 minutes before administration.
- Housing: Rodents were housed in stainless steel suspended-type cages (32.5 cm (D) x 19.5 cm (W) x 18 cm (H)). There was one rat per cage.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature: 21.7 – 22.2°C
- Humidity: 34 – 51%
- Air changes: 15 times/hour
- Photoperiod: 12 hours/day artificial lighting (06:00 – 18:00 lamp-lighting)

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: Concentration not provided.
- Justification for choice of vehicle: The test material readily mixed with water and is stable in water.

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg

DOSAGE PREPARATION: A specified amount of the test material was added to water for injection and suspended. A liquid at a specified concentration was prepared when it was used. Further, at the time of weighing, the test substance stock solution was regarded as 100 %, and no purity conversion was made.

Doses:

2000 mg/kg

No. of animals per sex per dose:

Six females were treated at a dose level of 2000 mg/kg.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All animals were observed once a day from the day following the day of completion of quarantine/acclimation to the day preceding the day of administration. 10 times a day on the day of administration. Twice a day (in the morning and afternoon) during the period from one day after administration to 13th day and once on the day of autopsy. The body weights of all animals were measured on the day before the day of administration, immediately before administration, after 1, 2, 3, 6, 10 and 13 day from administration and on the day of autopsy.
- Necropsy of survivors performed: yes, the body weight of all animals was measured 14 days after administration (17 to 18 hours after fasting), and aqueous solution (64.8 mg/mL, 5 mL/kg) of pentobarbital sodium was administered into the abdominal cavity of the animals to anesthetise and euthanise them. The external surface, internal organs and tissues were visually observed. Since there was no organ or tissue observed that was considered to have undergone a change in weight, no weight measurement was made. Liver and kidneys (right and left) were removed and fixed in 10 % neutral buffered formalin solution.

Statistics:

No statistical verification was carried out. The body weight, the average values and standard deviations of all animals at the time of each measurement and at administration were calculated.

Preliminary study:

Three females (Group 1) were treated at a dose level of 2000 mg/kg bw. In the absence of mortality or toxicity at a dose level of 2000 mg/kg bw, an additional group of 3 animals (Group 2) were treated at a dose level of 2000 mg/kg bw.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mL/kg bw

Based on:

test mat.

Mortality:

There was no mortality at a dose level of 2000 mL/kg bw for any of the animals.

Clinical signs:

other: There were no clinical signs observed during the study.

Gross pathology:

There was no abnormality observed in either of the groups.

Interpretation of results:

other: Not classified according to EU Criteria

Conclusions:

Under the conditions of this study, the test material was found to have a LD50 > 2000 mg/kg bw when it was administered orally to rats once.

Executive summary:

The acute oral toxicity of the test material using rats was investigated in accordance with the standardsied guideline OECD 423, under GLP conditions using the acute toxic class method.

2000 mg/kg bw of test material was administered orally once to Crj:CD(SD) IGS rats of 3 female animals of each group (totaling 6 animals) to investigate its toxicity. During the 2-week observation period, there was no death of any of the animals of each group, and any of them showed no abnormality. None of the animals showed any abnormality in their body weight and autopsy.

Under the conditions of this study, the test material was found to have a LD50 > 2000 mg/kg bw when it was administered orally to rats once.

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

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute toxicity: oral key study (Nakamura, 2004):

The acute oral toxicity of the test material using rats was investigated in accordance with the standardsied guideline OECD 423, under GLP conditions using the acute toxic class method. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).  

2000 mg/kg bw of test material was administered orally once to Crj:CD(SD) IGS rats of 3 female animals of each group (totaling 6 animals) to investigate its toxicity. During the 2-week observation period, there was no death of any of the animals of each group, and any of them showed no abnormality. None of the animals showed any abnormality in their body weight and autopsy.

Under the conditions of this study, the test material was found to have a LD50 > 2000 mg/kg bw when it was administered orally to rats once.

 

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance does not require classification with respect to acute toxicity.