N-isopropylmethacrylamide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was performed between 25 October 2007 and 21 November 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N-isopropylmethacrylamide

EC Number:

237-331-7

EC Name:

N-isopropylmethacrylamide

Cas Number:

13749-61-6

Molecular formula:

C7H13NO

IUPAC Name:

N-isopropylmethacrylamide

Test material form:

other: solid

Details on test material:

Sponsor's identification: N-Isopropyl methacrylamide (CAS number 13749-61-6) technical grade
Description: white crystalline solid
Batch number: 58838
Date received: 01 October 2007
Storage conditions: approximately 4°C in the dark

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Female Sprague-Dawley CD (Crl : CD® (SD) IGS BR) strain rats were supplied by Charles River (UK) Ltd. The females were nulliparous and non-pregnant.
- Age at study initiation: At the start of the study the animals were eight to twelve weeks of age.
- Weight at study initiation: 206 - 241 g. The bodyweight variation did not exceed ± 29% of the initial/mean bodyweight of any previously dosed animals.
- Fasting period before study: Overnight fast immediately before dosing and for approximately three to four hours after dosing.
- Housing: The animals were housed in groups of up to four in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet (e.g. ad libitum): Free access to food (Certified Rate and Mouse Diet) was allowed throughout the study.
- Water (e.g. ad libitum): Free access to mains drinking water was allowed throughout the study.
- Acclimation period: At least five days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Set to achieve limits of 19 to 25°C.
- Humidity (%): Set to acheive limits of 30 to 70%.
- Air changes (per hr): At least fifteen air changes per hour.
- Photoperiod (hrs dark / hrs light): lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

DMSO

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 30 mg/ml (for 300 mg/kg dose level) and 200 mg/ml (for 2000 mg/kg dose level).

- Justification for choice of vehicle: Dimethyl sulphoxide was used because the test material did not dissolve/suspend in distilled water or arachis oil BP.

MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg

DOSAGE PREPARATION: For the purpose of the study the test material was freshly prepared, as required, as a solution dimethyl sulphoxide.
All animals were dosed once only by gavage, using a metal cannula attached to a graduated syringe. The volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing. Treatment of animals was sequential. Sufficient time was allowed between each dose level to confirm the survival of the previously dosed animals.

Doses:

300 mg/kg and 2000 mg/kg

No. of animals per sex per dose:

1 female at 300 mg/kg.
5 females at 2000 mg/kg.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: Clinical observations were made 1/2, 1, 2, and 4 hours after dosing and then daily for fourteen days. Morbidity and mortality checks were made twice daily. Individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.

- Necropsy of survivors performed: yes - At the end of the observation period the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded.
No tissues were retained.

Results and discussion

Preliminary study:

Dose Level 300 mg/kg:
Individual clinical observations and mortality data are given in Table 1.

Mortality: There was no death
Clinical observations: No signs of systemic toxicity were noted during the observation period.
Bodyweight: Individual bodyweights and bodyweight changes are given in Table 2. The animal showed expected gains in bodyweight over the observation period.
Necropsy: Individual necropsy findings are given in Table 3. No abnormalities were noted at necropsy.

Based on this information, a dose level of 2000 mg/kg bodyweight was selected for the main test.

Effect levels

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

Dose Level 2000 mg/kg: Individual clinical observations and mortality data are given in Table 4.
There were no deaths.

Clinical signs:

other: Hunched posture, lethargy, ataxia and pilo-erection were noted in all animals treated at a dose level of 2000 mg/kg. One animal appeared normal one day after dosing and the remaining animals appeared normal two days after dosing.

Gross pathology:

Individual necropsy findings are given in Table 6.
No abnormalities were noted at necropsy.

Any other information on results incl. tables

See attached background material for Tables 1 -6.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral median lethal dose (LD50) of the test material in the female Sprague-Dawley CD strain rat was estimated to be greater than 2000 mg/kg bodyweight.

Executive summary:

Introduction.

The study was performed to assess the acute oral toxicity of the test material in the Sprague-Dawley CD strain rat. The method was designed to meet the requirements of the following:

• OECD Guidelines for Testing of Chemicals No 420 "Acute Oral Toxicity - Fixed Dose

Method" (200 I)

• Method BI bis Acute Toxicity (Oral) of Commission Directive 2004/73/EC

Method.

Following a sighting test at dose levels of 300 mg/kg and 2000 mg/kg, a further group of four fasted females was given a single oral dose of test material, as a solution in dimethyl sulphoxide, at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight

development were monitored during the study. All animals were subjected to gross necropsy.

Mortality.

There were no deaths.

Clinical Observations.

Signs of systemic toxicity noted in animals treated at a dose level of 2000 mg/kg were hunched posture, lethargy, ataxia and pilo-erection. There were no signs of systemic toxicity noted in the animal treated at a dose level of 300 mg/kg.

Bodyweight.

All animals showed expected gains in bodyweight.

Necropsy.

No abnormalities were noted at necropsy.

Conclusion.

The acute oral median lethal dose (LD₅₀) of the test material in the female Sprague-Dawley CD strain rat was estimated to be greater than 2000 mg/kg bodyweight.