4,6-Pyrimidinediamine, 2-[5-fluoro-1-[(2-fluorophenyl)methyl]-1H-pyrazolo[3,4-b]pyridin-3-yl]-5-[(1E)-2-phenyldiazenyl]-

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 Apr - 20 Nov 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment, No. 23, "Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures"

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-{5-fluoro-1-[(2-fluorophenyl)methyl]-1H-pyrazolo[3,4-b]pyridin-3-yl}-5-[(1E)-2-phenyldiazen-1-yl]pyrimidine-4,6-diamine

EC Number:

811-933-5

Cas Number:

1350653-29-0

Molecular formula:

C23 H17 F2 N9

IUPAC Name:

2-{5-fluoro-1-[(2-fluorophenyl)methyl]-1H-pyrazolo[3,4-b]pyridin-3-yl}-5-[(1E)-2-phenyldiazen-1-yl]pyrimidine-4,6-diamine

Test material form:

solid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test medium of the only test concentration and the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the only test item concentration during the test period, duplicate samples from the test medium of the only test concentration and the control were collected at the end of the test (after 48 hours) by pouring together the contents of the test beakers of each treatment.
All samples were diluted by a factor of 2 with acetonitrile.
Additional samples of the control and the dilution solvent were taken at each sampling test start and test end without any sample treatment.

Test solutions

Vehicle:

no

Details on test solutions:

Test Concentration:
Nominal: Filtrate of 100 mg test item/L and a control. The concentration was measured analytically and was below the limit of quantification (LOQ) of 0.1 µg test item/L.
Control:
In the control, test water was used without addition of the test item.
Dosage of Test Item:
The test item was not well soluble in test water. To avoid physical effects of undissolved test item on the daphnids, no concentration above the solubility limit of the test item in test water was tested. Therefore, a supersaturated stock solution of nominal 100 mg test item/L was prepared by suspending 100.0 mg of test item in 1000 mL test water. The stock solution was stirred for 23.5 hours in the dark to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration (0.45 µm cellulose acetate filter) and the filtrate was used as test medium.
The test medium was prepared just before introduction of the daphnids (= start of the test).

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna (Straus), clone 5
Age at Test Start: From 1 to 18 hours old Origin:
The daphnids introduced in the test were taken from ibacon's in house laboratory culture.
Breeding Conditions:
The daphnids were bred in the laboratories of ibacon under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in Elendt M4 medium. The test organisms were not first brood progeny. The daphnids in the stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus) freshly grown in the laboratories of ibacon.
Acclimatisation:
Was not necessary, since the test was performed in the same medium as the culturing.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

Water Hardness: 2.5 mmol/L (= 250 mg/L) as Calcium Carbonate

Test temperature:

19.8 to 21.1 °C at test start; 20.1 °C at test end

pH:

7.9 at test start; 7.8 to 7.9 at test end; and thus the pH-value did not vary by more than 1.5 units

Dissolved oxygen:

6.1 to 8.9 mg/L at test start; 8.4 to 8.9 mg/L at test end

Nominal and measured concentrations:

Nominal: Filtrate of 100 mg test item/L and a control. The concentration was measured analytically and was below the limit of quantification (LOQ) of 0.1 µg test item/L.

Details on test conditions:

Test Environment:
Controlled environment room
Measurement of pH, Dissolved Oxygen and Water Temperature:
The water temperature, pH-values and dissolved oxygen concentrations were determined at test start and test end in each treatment group.
Water Temperature:
19.8 to 21.1 °C at test start; 20.1 °C at test end
pH-Values:
7.9 at test start; 7.8 to 7.9 at test end
Dissolved Oxygen Concentration:
6.1 to 8.9 mg/L at test start; 8.4 to 8.9 mg/L at test end
Light Regime: 16 h light : 8 h dark
Light Intensity: The light intensity was 700 to 970 lux (measured once during the test).
Recording: Test conditions were recorded with suitable instruments and documented in the raw data.

Reference substance (positive control):

yes

Remarks:

For the evaluation of the quality of the Daphnia clone and the consistency of the experimental conditions, the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Value refer to measured test concentrations below the LOQ of 0.1 µg test. item/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 0.1 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

After 48 hours of exposure to Fluoroazopyrimidine no immobilisation of the test animals were observed in the control and in the only test concentration of nominal 100 mg test item/L.

Results with reference substance (positive control):

In the most recent test with the reference item potassium dichromate the EC50 after 24 hours was determined to be 0.932 mg test item/L, indicating that the sensitivity of the Daphnia was consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg potassium dichromate/L).

Reported statistics and error estimates:

No statistical analysis was performed.
The EC50 could not be quantified due to the absence of toxicity of the test item. The NOEC and the LOEC were determined directly from the raw data.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

Control Immobilisation Rate was 0 % and furthermore no daphnid showed signs of disease or stress. Dissolved Oxygen Concentration was above or equal 7.8 mg O2/L in the control and test vessels at the end of the test.

Conclusions:

The toxic effect of the test item Fluoroazopyrimidine to Daphnia magna was assessed in a static limit test. The 48-hour NOEC was determined to be at least the filtrate of nominal 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominal 100 mg test item/L or the limit of solubility have not been tested according to the recommendations of the test guidelines. The 48-hour LOEC and the 48-hour EC50 were clearly higher than the filtrate of nominal 100 mg test item/L. These values could not be quantified due to the absence of toxicity of Fluoroazopyrimidine up to the filtrate of nominal 100 mg test item/L, the concentration representing the limit of solubility.
The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to the Limit of Quantification.

Executive summary:

Title:

Fluoroazopyrimidine: Acute Toxicity to Daphnia magna in a Static 48-hour Immobilisation Limit Test

Purpose:

The purpose of this study was to determine the influence of the test item Fluoroazopyrimidine on the mobility of Daphnia magna.

For this purpose, young daphnids (< 24 hours old) were exposed in a static test to the only concentration of 100 mg/L under defined conditions for 48 hours. The recorded effects were the mobility of the daphnids after 24 and 48 hours.

This limit-test was performed in compliance with the test guidelines in order to demonstrate that the test item has no toxic effects on the daphnids up to this concentration.

The test method of application and the test system are recommended by the test guidelines and Daphnia magna is the recommended test species. The purpose of the analytical part of this study was to verify the concentration of the test item in the test medium.

Guidelines:

OECD Guideline for Testing of Chemicals No. 202: "Daphnia sp., Acute Immobilisation Test" adopted April 13, 2004

OECD Series on Testing and Assessment, No. 23, "Guidance Document on Aqueous-phase Aquatic Toxicity Testing of Difficult Test Chemicals", 2nd Ed., February 08, 2019

SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II (part A; Section 4) and Annex III (part A; Section 5) of directive 91/414

 

Materials and Methods

Test Item: Fluoroazopyrimidine

Test Species: Daphnia magna, clone 5; 1 to 18 hours old

Source: The daphnids introduced in the test were taken from ibacon's in-house laboratory culture.

Test Design: This study encompassed two treatment groups (one test item measured concentration of 0.1 µg test item/L and one control) each containing 20 individuals. The mobility of the daphnids was determined in a static 48-hour test by visual observation after 24 and 48 hours.

Endpoints: Number of immobile organisms after 24 and 48 hours

Test Concentrations: Nominal: Filtrate of 100 mg test item/L and a control. The concentration was measured analytically and was below the limit of quantification (LOQ) of 0.1 µg test item/L.

Test Conditions: Water temperature: 19.8 to 21.1 °C; pH value: 7.8 to 7.9; dissolved oxygen concentration: 6.1 to 8.9 mg/L; photoperiod: 16 h light - 8 h dark; light intensity: 700 to 970 lux; and thus were within the ranges requested by guideline OECD 202.

 

Results

Biological test results:

After 48 hours of exposure no immobilisation of the test animals was observed in the control and in the only tested concentration of < 0.1 µg test item/L.

Analytical test results:

The quantification of the test item Fluoroazopyrimidine in the test samples was performed using liquid chromatography with MS/MS detection.

The measured values are below the Limit of Quantification but indicate a recovery in the low nano gram range for the filtrate and a decrease of test concentration over the course of the test.

 

Conclusion:

The toxic effect of the test item Fluoroazopyrimidine to Daphnia magna was assessed in a static limit test. The 48-hour NOEC was determined to be at least the filtrate of nominal 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominal 100 mg test item/L or the limit of solubility have not been tested according to the recommendations of the test guidelines. The 48-hour LOEC and the 48-hour EC50 were clearly higher than the filtrate of nominal 100 mg test item/L. These values could not be quantified due to the absence of toxicity of Fluoroazopyrimidine up to the filtrate of nominal 100 mg test item/L, the concentration representing the limit of solubility.

The initial concentrations and the maintenance of the exposure concentrations during the test were determined in the analytical part. All reported results refer to the Limit of Quantification. This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.