3,7-dihydropurin-6-one;sodium

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-10-25 to 2018-01-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted December 2001

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dihydropurin-6-one;sodium

Cas Number:

45738-97-4

Molecular formula:

C5H3N4NaO

IUPAC Name:

3,7-dihydropurin-6-one;sodium

Test material form:

solid: particulate/powder

Details on test material:

- Appearance: White powder
- Purity / Composition: 98%
- Test item storage: Room temperature

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: approx. 8 weeks old
- Weight at study initiation: 143 - 162 g
- Housing: up to 5 animals of the same sex and same dosing group together) in polycarbonate cages containing sterilized sawdust as bedding material (Lignocel S 8-15) equipped with water bottles.
- Diet (e.g. ad libitum): Yes, pelleted rodent diet (SM R/M-Z from SSNIFF Spezialdiäten GmbH, Soest, Germany)
- Water (e.g. ad libitum): Yes, tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 47 - 56
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

A single dose of test item was administered to the appropriate animals by oral gavage on Day 1, using a syringe with a plastic gavage cannula attached (dosing volume: 10 mL/kg bw). Animals were deprived of food overnight (for a maximum of 20 hours) prior to dosing and until 3-4 hours after administration of the test item. Water was available.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

6 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: Throughout the study, animals were observed for general health/mortality and moribundity twice daily, in the morning and at the end of the working day. Animals were not removed from cage during observation, unless necessary for identification or confirmation of possible findings.
- Frequenvy of weighing: Animals were weighed individually on Day 1 (predose), 8 and 15. A fasted weight was recorded on the day of dosing.
- Necropsy of survivors performed: yes, all animals surviving to the end of the observation period were sacrificed by oxygen/carbon dioxide procedure. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded
- Clinical signs: Postdose observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter. The observation period was 14 days. All the animals were examined for reaction to dosing. The onset, intensity and duration of these signs was recorded (if appropriate). Signs were graded for severity and the maximum grade was predefined at 3 or 4. Grades were coded as slight (grade 1), moderate (grade 2), severe (grade 3) and very severe (grade 4). For certain signs, only its presence (grade 1) or absence (grade 0) was scored.

Statistics:

No statistical analysis was performed (the method used is not intended to allow the calculation of a precise LD50 value).

Results and discussion

Preliminary study:

n.a.

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No test item related mortality occurred. One animal was killed in extremis on Day 1, due to technical dosing error.

Clinical signs:

other: Hunched posture, piloerection and/or uncoordinated movements were noted for the animals on Days 1 and/or 2. Abnormal posture of the left foreleg, head tilt, rales, shallow respiration, gasping and salivation were noted directly after dosing for the animal

Gross pathology:

No test item related abnormalities were found at macroscopic post mortem examination of the animals. Perforation of the Esophagus was noted for the animal killed in extremis on Day 1. This technical dosing error was considered not toxicologically relevant.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute oral toxicity study in rats conducted according to OECD 423 no mortality occurred at the limit dose of 2000 mg/kg bw. Hence, the LD50 value was determined to be greater than 2000 mg/kg bw.

Executive summary:

In an acute oral toxicity study (acute toxic class method, OECD 423), six 8 weeks old, female Wistar rats were given a single oral dose of the test item (98% purity) in water at the limit dose of 2000 mg/kg bw and were observed for 14 days. All animals survived until the end of the study showing only mild signs of toxicity, except one animal, which was killed in extremis on Day 1, due to technical dosing error. The most relevant clinical findings were hunched posture, piloerection and/or uncoordinated movements during Day 1 and/or 2. Throughout the 14-day observation period, the body weight gain of the test animals was within the normal range of variation for this strain. At necropsy, no treatment-related macroscopic findings were observed in any animal. Based on the results from this study, the oral LD50 in rats is considered to exceed 2000 mg/kg bw.