2-(chloromethyl)-4-methylquinazoline

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-07-23 to 2007-09-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Version / remarks:

2004

GLP compliance:

yes (incl. QA statement)

Remarks:

dated 2006-12-21

Analytical monitoring:

yes

Details on sampling:

- Sampling method: The samples were five hundredfold diluted with a mixture of Acetonitrile:Water = 4:6 and the content of the test item was determined by the reverse phase HPLC method.
- Sampling intervals/times for pH measurements: The test solutions were analysed at the start of the test and then at appropriate time intervals in order to get at least six other data points in the range of 20 to 70% hydrolysis. Three samples were analysed at each occasion. The pH of each buffer solution was checked with a calibrated pH meter.

Buffers:

- pH: 4.0; 7.0; 9.0
- Composition of buffer:
pH 4.0: 4 ml 0.2 M Sodium hydroxide and 500 ml 0.2 M Potassium hydrogen phthalate were diluted to 2000 ml with ultra-pure water
pH 7.0: 295.6 ml 0.2 M Sodium hydroxide and 500 ml 0.2 M Potassium dihydrogen phosphate were diluted to 2000 ml with ultra-pure water
pH 9.0: 214.0 ml 0.2 M Sodium hydroxide and 500 ml 0.2 M Boric acid and Potassium chloride were diluted to 2000 ml with ultra-pure water

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: HPLC system: Merck-Hitachi LaChrom HPLC system; balance: BP 221 S Sartorius; L2200 P Sartorius; pH Meter: OP-211/1, Radelkis; Thermostat: LP 132; Ultrasonic bath: Elmasonic S300 H
- Sterilisation method: Hot Air Steriliser: ATP line FED, WTB Binder; Water purification system: Millipore, Direct Q3, Fomno 7334I
- Measures taken to avoid photolytic effects: The hydrolysis reaction will be carried out using a dark thermostat to avoid photolytic effects.
- Measures to exclude oxygen: Nitrogen will be bubbled into the water for five minutes before the preparation of the solutions in order to exclude oxygen.

TEST MEDIUM
- Volume used/treatment: 1000 ml sterile solutions were prepared at pH 4, 7 and 9. Solutions were transferred into 20 ml stoppered tubes. 20 tubes were stored both at 25+-0.5°C and at 50+-0.5°C.
- Kind and purity of water: ultra-pure water (Millipore)
- Preparation of test medium: The test item concentration in the buffer solutions was approximately 1.5 mg/ml.

Duration:

740 h

pH:

4

Temp.:

25 °C

Initial conc. measured:

1 528 mg/L

Duration:

364 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

1 528 mg/L

Duration:

740 h

pH:

7

Temp.:

25 °C

Initial conc. measured:

1 536 mg/L

Duration:

364 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

1 536 mg/L

Duration:

740 h

pH:

9

Temp.:

25 °C

Initial conc. measured:

1 547 mg/L

Duration:

430 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

1 547 mg/L

Number of replicates:

one replicate per pH and temperature

Statistical methods:

A calibration curve was developed using the following concentrations: 0.02; 0.05; 0.1; 0.5; 1; 5; and 10 µg test item/ml. The measured intensities were plotted against the retention time.

Preliminary study:

In the course of the preliminary test (Study Code: 06/319-336AN) the test item proved to be hydrolytically unstable at pH 4, 7 and 9. Concentration decreased by more than 20% after 5 days at 50°C at each of the tested pH values.

Transformation products:

not specified

pH:

4

Temp.:

25 °C

DT50:

> 96 d

Type:

(pseudo-)first order (= half-life)

pH:

7

Temp.:

25 °C

DT50:

> 96 d

Type:

(pseudo-)first order (= half-life)

pH:

9

Temp.:

25 °C

DT50:

> 96 d

Type:

(pseudo-)first order (= half-life)

pH:

4

Temp.:

50 °C

Hydrolysis rate constant:

0.003 h-1

DT50:

224 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: y=-0.0013x+3.1708; R2=0.9979

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.003 h-1

DT50:

207 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: y=-0.0015x+3.1814; R2=0.9995

pH:

9

Temp.:

50 °C

Hydrolysis rate constant:

0.002 h-1

DT50:

294 h

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: y=-0.001x+3.1911; R2=0.9972

Details on results:

TEST CONDITIONS
- pH, sterility, temperature, and other experimental conditions maintained throughout the study: Yes

The hydrolysis of the test item was less than 20% after 31 days at 25°C in pH 4, 7, and 9 buffer solutions. Therefore the half-life of the test item is considered to be higher than 96 days at 25°C. (Estimated half-life was calculated assuming 20 % hydrolysis after 31 days based on equations 1 and 3 ( for equations refer to section „Any other information on materials and methods incl. tables”)).

For the tests carried out at 50°C the log transformed data of the test item concentrations against time were plotted. A line was fitted on the measured data and the rate constant and the half-life were obtained from its slope, according to equations 2 and 3. Results are summarised in table 1.

Equations:

k_obs= (2.303/t) * log (c₀/c_t)   (equation 1)

k_obs= - slope * 2.303              (equation 2)

Calculation of the half-life:

t_1/2= 0.693/k_obs                    (equation 3)

Table 1: Rate constants and half-lives measured at 50°C

pH	Slope	Kobs	t1/2
4	-0.001341	0.00309	224 h
7	-0.001456	0.00335	207 h
9	-0.001023	0.00236	294 h

Validity criteria fulfilled:

yes

Conclusions:

The hydrolysis half-lives were calculated to be >96 days at pH 4, 7, 9 and 25°C, 224 h at pH 4 and 50 °C, 207 h at pH 7 and 50 °C and 294 h at pH 9 and 50 °C.

Description of key information

 Hydrolysis half-life: >96 days at pH 4, 7, 9 at 25°C

Key value for chemical safety assessment

Half-life for hydrolysis:

96 d

at the temperature of:

25 °C

Additional information

A preliminary and a main test were conducted according to OECD 111 and GLP.

In the preliminary test it was determined, that the concentration of the test item decreased by more than 20 % after 5 days at 50°C at each of the tested pH values. Thus, the test item is considered to be hydrolytically unstable.

In the main test hydrolysis half-lives were determined at pH 4, 7 and 9 at 25°C to be > 96 days.

The identification of formed hydrolysis products in amounts of >= 10% was not conducted, as according to the version of OECD test guideline 111 used (12 May 1981) the identification of hydrolysis products was not required. However, it is generally known that heteroaromatic pyrimidine moities are stable towards hydrolysis and chlormethyl groups can hydrolyse to hydroxymethyl. This assumption is supported by the HPLC chromatograms in the study. Therefore the TIER 3 hydrolysis study is not required.