pymetrozine (ISO); (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)-1,2,4-triazin-3(2H)-one

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Nov 1992 to 22 Mar 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

1981

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: US Federal Register 40 CFR part 796.1840

Version / remarks:

1985

Deviations:

no

GLP compliance:

yes

Type of method:

flask method

Specific details on test material used for the study:

Treatment of test material prior to testing:

Since test substance is known to hydrolyse at pH values below 7, solutions for the experiment were prepared containing around ten times the amount of the substance necessary for saturation to ensure that the solutions remained saturated during the experiment.
On each of the first three days of the experiment, 3 such samples were prepared in centrifuge tubes and equilibrated by continuous shaking at 30.0 °C (± 0.1 °C) in a thermostatically controlled water bath. On the fourth day the temperature was reduced to 25.0 °C (± 0.1 °C), at which temperature each sample was shaken further for at least 24 hours. The dispersions were then centrifuged for 40 minutes at 30000, 40000 or 50000 G in a thermostated (25.0 °C) centrifuge. After centrifugation it was noted that all the test solutions were still cloudy with residual test substance at the bottom of the centrifuge tube. The test solutions were therefore decanted into similar centrifuge tubes, taking care to remove much but not all of the excess test substance. The centrifuge tubes were then re-equilibrated by continuous shaking at 25.0 °C (± 0.1 °C) for a further 3 days. Thereafter the majority of the excess test substance was removed by pipette and the tubes then centrifuged for 80 minutes at 50000 G in the thermostated (25 °C) centrifuge. After centrifugation clear solutions were obtained. Each test solution, however, still contained excess test substance. Subsequently, an aliquot from each of the clear, saturated solutions was analysed by high performance liquid chromatography, HPLC. Equilibration at 30.0 °C for different lengths of time gave the same results indicating that true saturation had been reached and maintained.

Key result

Water solubility:

290 mg/L

Conc. based on:

test mat.

Incubation duration:

>= 5 - <= 7 d

Temp.:

25 °C

pH:

6.4

Remarks on result:

other: RSD: 0.91% (average of 9 samples)

Details on results:

An overview of the results is presented in ‘Any other information on results incl. tables’.

Table: Equilibration at 30.0 °C for 3, 2 and 1 days

sample number	1	2	3	4	5	6	7	8	9
Weight of test substance in 40.0 mL of water [mg]	80.3	80.1	80.2	79.7	78.6	82.0	84.3	82.0	82.3
number of days at 30.0 °C	3	3	3	2	2	2	1	1	1
number of days at 25.0 °C	4	4	4	4	4	4	4	4	4
Centrifugation [G]	50000	50000	50000	50000	50000	50000	50000	50000	50000
pH of clear solution	6.52	6.60	6.35	6.55	6.49	6.34	6.36	6.45	6.37
average pH value	6.5			6.5			6.4
water solubility in mg/L 1 determination 2 determination 3 determination average	287.210 292.564 291.560 290.445	285.942 285.751 286.733 286.142	286.502 287.719 282.898 285.142	290.344 287.923 288.638 288.968	289.784 290.583 291.534 290.634	287.190 286.787 286.411 286.796	292.335 292.448 286.286 290.356	290.590 290.394 292.585 291.190	291.015 291.568 290.501 291.028
total average	287.431 mg/L			288.799 mg/L			290.858 mg/L
rel. standard deviation	1.0 %			0.64 %			0.66 %

Conclusions:

The water solubility of the test item was determined to be 290 mg/L in water at 25 °C and pH 6.4.

Executive summary:

The water solubility of the test item has been determined using the flask method in accordance with OECD TG 105 and in compliance with GLP. The solubility (average of 9 samples), of the pure test substance in water was determined to be 290 mg/L at 25 °C and pH 6.4.

Description of key information

290 mg/L in water at 25 °C, OECD 105, flask method, Rodler 1993

Key value for chemical safety assessment

Water solubility:

290 mg/L

at the temperature of:

25 °C