Pyrimidine, 4-chloro-6-ethenyl-5-fluoro-

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 November 2016 to 29 November 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-chloro-6-ethenyl-5-fluoropyrimidine

EC Number:

940-222-3

Cas Number:

1403893-61-7

Molecular formula:

C6 H4 Cl F N2

IUPAC Name:

4-chloro-6-ethenyl-5-fluoropyrimidine

Test material form:

liquid

Details on test material:

received as orange brown liquid

Specific details on test material used for the study:

Batch 2000533255 Purity/Composition 99.2% Test item storage In refrigerator (2-8°C) Stable under storage conditions until Not indicated

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

Species Rat, Wistar strain Crl:WI (Han) (outbred, SPF-Quality). Recognized by international guidelines as the recommended test system (e.g. OECD, EC).
Source: Charles River Deutschland, Sulzfeld, Germany.
Number of animals 6 Females (nulliparous and non-pregnant). Each dose group consisted of 3 animals.
Age and body weight Young adult animals (approx. 8-10 weeks old) were selected. Body weight variation did not exceed +/- 20% of the sex mean.
Identification Earmark and tail mark
Health inspection At least prior to dosing. It was ensured that the animals were healthy and without any abnormality that might have affected the study integrity.
Conditions
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, at least 10 air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.
Accommodation
Group housing of 3 animals per cage in labeled Makrolon cages (MIV type; height 18 cm.) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) and paper as cage-enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
Acclimatization period was at least 5 days before start of treatment under laboratory conditions.
Diet Free access to pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
Water
Free access to tap water.
Diet, water, bedding and cage enrichment evaluation for contaminants and/or nutrients was performed according to facility standard procedures. There were no findings that could interfere with the study.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Details on oral exposure:

Method Oral gavage, using plastic feeding tubes. The test item preparations were stirred on a magnetic stirrer during dosing.
Fasting Animals were deprived of food overnight prior to dosing and until 3-4 hours after administration of the test item. Water was available ad libitum.
Frequency Single dosage on Day 1.
Dose level (volume) 300 mg/kg (10 mL/kg) body weight. 50 mg/kg (10 mL/kg) body weight.

Doses:

Initially, PF-06645243 was administered by oral gavage to three female Wistar rats at 300 mg/kg body weight. In a stepwise procedure one additional group of three females was dosed at 50 mg/kg body weight.

No. of animals per sex per dose:

3f/group

Control animals:

not specified

Details on study design:

The toxicity of the test item was assessed by stepwise treatment of groups of 3 females. The first group was treated at a dose level of 300 mg/kg. The absence or presence of mortality of animals dosed at one step determined the next step, based on the test procedure defined in the guidelines. The onset, duration and severity of the signs of toxicity were taken into account for determination of the time interval between the dose groups.

Method Oral gavage, using plastic feeding tubes. The test item preparations were stirred on a magnetic stirrer during dosing.
Fasting Animals were deprived of food overnight prior to dosing and until 3-4 hours after administration of the test item. Water was available ad libitum.
Frequency Single dosage on Day 1.
Dose level (volume) 300 mg/kg (10 mL/kg) body weight. 50 mg/kg (10 mL/kg) body weight.

Observations
Mortality/Viability Twice daily. Animals showing pain, distress or discomfort, which was considered not transient in nature or was likely to become more severe, were sacrificed for humane reasons based on OECD guidance document on humane endpoints (ENV/JM/MONO/ 2000/7). The time of death was recorded as precisely as possible.
Body weights Days 1 (pre-administration) 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. The signs were graded according to fixed scales and the time of onset, degree and duration were recorded: Maximum grade 4: grading slight (1) to very severe (4) Maximum grade 3: grading slight (1) to severe (3) Maximum grade 1: presence is scored (1).
Necropsy The animal surviving to the end of the observation period was sacrificed by oxygen/carbon dioxide procedure. All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities recorded.

Interpretation
The oral LD50 value of the test item was ranked within the following ranges: 0-5, 5-50, 50300 or 300-2000 mg/kg b.w. or as exceeding 2000 mg/kg b.w. The LD50 cut-off value was established based on OECD guideline 423. No statistical analysis was performed (The method used is not intended to allow the calculation of a precise LD50 value).
The results were evaluated according to:
• Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments).
• Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Statistics:

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

Results and discussion

Effect levels

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

< 50 mg/kg bw

Based on:

test mat.

Mortality:

At 300 mg/kg, all animals were found dead within three hours after dosing.
At 50 mg/kg, one animal was found dead on Day 1 and one animal was found dead on Day 2.

Clinical signs:

other: At 300 mg/kg, lethargy, hunched posture, quick breathing, shallow respiration and piloerection were noted for all animals on Day 1. At 50 mg/kg, lethargy, hunched posture, lateral recumbency, piloerection, salivation, lean appearance, ptosis, slow brea

Gross pathology:

Abnormalities of the stomach (glandular mucosa and/or forestomach: discolouration, dark red) and gastrointestinal tract contents (stomach, duodenum, jejunum, and ileum: gelatinous) were noted for the animals treated at 300 and 50 mg/kg, found dead during the study
No abnormalities were found at macroscopic post mortem examination of the surviving animal.
Beginning autolysis was noted for one of the animals found dead. This was considered not toxicologically relevant.

Applicant's summary and conclusion

Interpretation of results:

Category 1 based on GHS criteria

Conclusions:

In consultation with the Sponsor, the study was terminated after treating one group at 300 mg/kg and one group at 50 mg/kg due to severe effects and for animal welfare reasons.
The oral LD50 value of PF-06645243 in Wistar rats was established to be below 50 mg/kg body weight.
Based on these results:
• according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments), PF-06645243 should be classified as: fatal if swallowed (Category 1 or 2) for acute toxicity by the oral route.
• according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments), PF-06645243 should be classified as Category 1 and should be labeled as H300: Fatal if swallowed or Category 2 and should be labeled as H300: Fatal if swallowed.

Executive summary:

Assessment of acute oral toxicity with  PF-06645243 in the rat (Acute Toxic Class Method).

The study was carried out based on the guidelines described in: OECD No.423 (2001) "Acute Oral Toxicity, Acute Toxic Class Method" Commission Regulation (EC) No 440/2008, B1  tris:  "Acute Oral Toxicity, Acute Toxic Class Method" EPA, OPPTS 870.1100 (2002), "Acute Oral Toxicity" JMAFF Guidelines (2000), including the most recent revisions.

Initially,  PF-06645243 was administered by oral  gavage  to three female Wistar rats at 300 mg/kg body weight. In a stepwise procedure one additional group of three females was dosed at 50 mg/kg body weight. All animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed on the day of death or after terminal sacrifice (Day 15).

At 300 mg/kg, all animals were found dead within three hours after dosing.

At 50 mg/kg, one animal was found dead on Day 1 and one animal was found dead on Day 2.

At 300 mg/kg, lethargy, hunched posture, quick breathing, shallow respiration and piloerection were noted for all animals on Day 1.

At 50 mg/kg, lethargy, hunched posture, lateral recumbency, piloerection, salivation, lean appearance,  ptosis,  slow breathing and/or shallow respiration were noted for the animals between Days 1 and 13.

The surviving animal showed body weight loss between Days 1 and 8 but gained body weight over the whole study period.

Abnormalities of the stomach (glandular  mucosa  and/or forestomach: discolouration, dark red) and gastrointestinal tract contents (stomach, duodenum, jejunum, and ileum: gelatinous) were noted for the animals treated at 300 and 50 mg/kg, found dead during the study

No abnormalities were found at macroscopic post  mortem  examination of the surviving animal.

In consultation with the Sponsor, the study was terminated after treating one group at 300 mg/kg and one group at 50 mg/kg due to severe effects and for animal welfare reasons.

The oral LD50 value of  PF-06645243 in Wistar rats was established to be below 50 mg/kg body weight.

Based on these results:

• according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments),  PF-06645243 should be classified as: fatal if swallowed (Category 1 or 2) for acute toxicity by the oral route.

• according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments),  PF-06645243 should be classified as Category 1 and should be labeled as H300: Fatal if swallowed or Category 2 and should be labeled as H300: Fatal if swallowed.