(4aR*, 8aR*)-1-bromo-4a,5,9,10,11,12-hexahydro-3-methoxy-6H-benzofuro[3a,3,2-ef] [2]benzazepin-6-one hydrochloride (1:1)

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-06-18 to 2002-03-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

yes

Remarks:

The lighting conditions during the incubation period not reported

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

The lighting conditions during the incubation period not reported

GLP compliance:

yes (incl. QA statement)

Remarks:

The Federal Office of Public Health, the Swiss Agency for the Environment, Forests and Landscape and the Intercantonal Office for the Control of Medicines with respect to the compliance with the Swiss legislation on Good Laboratory Practice.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals for the parent/transformation products: at the beginning and after 2.4 and 120 hours
- Sampling method: no data
- Sampling methods for the volatile compounds, if any: not applicable
- Sampling intervals/times for pH measurements: not applicable
- Sampling intervals/times for sterility check: not applicable
- Sample storage conditions before analysis: not applicable
- Other observation, if any: no data

Buffers:

- pH: 4.0, 7.0, and 9.0
- Type and final molarity of buffer: buffer pH 4 biphthalate, buffer pH 7 phosphate, buffer pH 9 borate, no final molarity reported
- Composition of buffer: no data

Details on test conditions:

TEST SYSTEM
- Type, material and volume of test flasks, other equipment used: glass flasks which were stoppered or sealed with an inert material
- Sterilisation method: no data
- Lighting: no data
- Measures taken to avoid photolytic effects: no data
- Measures to exclude oxygen: Nitrogen was passed through the buffer solutions for about 5 minutes except when freshly sterilized.
- Details on test procedure for unstable compounds: no data
- Details of traps for volatile, if any: not applicable
- If no traps were used, is the test system closed/open: not applicable
- Is there any indication of the test material adsorbing to the walls of the test apparatus? no

TEST MEDIUM
- Volume used/treatment: 50mL
- Kind and purity of water: Milli-Q
- Preparation of test medium:
Hydrolysis at 50°C
*pH 4.0: A 12.00 mg sample of T002102 was dissolved in 100 mL buffer solution (pH 4.0) to prepare a test solution of 120.0 µg/mL.
*pH 7.0, Preliminary Test: A 11.55 mg sample of T002102 was dissolved in 100 mL buffer solution (pH 7.0) to prepare a test solution of 115.5 µg/mL.
*pH 7.0, Main Test: A 10.75 mg sample of T002102 was dissolved in 100 mL buffer solution (pH 7.0) to prepare a test solution of 107.5 µg/mL.
*pH 9.0: A 10.33 mg sample of T002102 was dissolved in 100 mL buffer solution (pH 9.0) to prepare a test solution of 103.3 µg/mL.

These solutions were ultrasonicated for 10 minutes and filtrated (0.45 pm). Two aliquots of each test solution of approximately 50 ml each were transferred into 50 ml Erlenmeyer flasks in order to perform a duplicate test.

Hydrolysis at 39 °C
*pH 7.0: A 10.91 mg sample of T002102 were dissolved in 100 mL buffer solution (pH 7.0) with aid of sonication to prepare a test solution of 109.1 µg/mL. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

Hydrolysis at 29°C
*pH 7.0: A 11.46 mg sample of T002102 were dissolved in 100 mL buffer solution (pH 7.0) with aid of sonication to prepare a test solution of 114.6 ug/mL. Two aliquots of this test solution of approximately 50 mL each were transferred into 50 mL Erlenmeyer flasks in order to perform a duplicate test.

- Renewal of test solution: not applicable
- Identity and concentration of co-solvent: not applicable

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Dissolved oxygen: no data

Duration:

840 h

pH:

4

Temp.:

50 °C

Initial conc. measured:

118.5 - 118.7 other: µg/mL

Duration:

120 h

pH:

7

Temp.:

50 °C

Initial conc. measured:

111.3 - 111.5 other: µg/mL

Duration:

120 h

pH:

9

Temp.:

50 °C

Initial conc. measured:

83.8 - 88.4 other: µg/mL

Duration:

28 h

pH:

7

Temp.:

39 °C

Initial conc. measured:

111.4 - 114.3 µg/L

Duration:

162 h

pH:

7

Temp.:

29 °C

Initial conc. measured:

71.1 - 74.5 µg/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Statistical methods:

no data

Preliminary study:

The preliminary hydrolysis tests were performed at 50°C at pH 4.0, pH 7.0 and pH 9.0. Aliquots of each test solution were analyzed at the beginning and after 2.4 and 120 hours. Further hydrolysis tests were performed at 50°C, 39°C and 29°C in the buffered test solution at pH 7.0, due to the instability of the test item found in the preliminary test at 50°C.

pH 4.0
The decrease of test item concentration at pH 4.0 between 0 hours and 5 days was about 18%. Between 5 days and 35 days only 11 % of additional degradation have been observed, which indicates a very slow degradation at this pH value. If the concentration found after 23 hours is considered 100 %, the decrease is only 3 % in the following 100 hours and 12 to 18 % in the following 820 hours. A peak at about 19 minutes indicates a slight increase of a degradation product. According to the data obtained during prolonged incubation period, T002102 seems to be hydrolytically stable at pH 4.0 with an estimated half-life time from about 200 days at 50°C. Therefore, no further testing was performed.

pH 7.0
Preliminary tests show T002102 is not stable at pH 7.0. Therefore the test at 50 °C was repeated in the range of 20 % to 70 % degradation. The half-life time of T002102 at 50 °C and pH 7.0 was calculated to be 4 hours. The half-life time at pH 7.0 and 39 °C was calculated to be 23 hours. The half-life time at pH 7.0 and 29 °C was calculated to be 92 hours (4 days).

pH 9.0
The results of pH 9.0 show that T002102 is very unstable at 50 °C. The degradation of T002102 at pH 9.0 was determined to be > 50 % after 2.4 hours of incubation. According to the EEC Directive 92/69, Section C.7, it can be concluded, that the estimated half-life time at pH 9.0 is shorter than one day under representative environmental conditions. Therefore, no further testing was necessary at this pH-value.

Transformation products:

not measured

pH:

4

Temp.:

50 °C

DT50:

ca. 200 d

Type:

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

pH:

9

Temp.:

25 °C

DT50:

< 1 d

Type:

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

pH:

7

Temp.:

50 °C

Hydrolysis rate constant:

0.18 h-1

DT50:

4 h

Type:

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

Remarks on result:

other: rate constant = 0.018313 1/hours

pH:

7

Temp.:

39 °C

Hydrolysis rate constant:

0.03 h-1

DT50:

23 h

Type:

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

Remarks on result:

other: rate constant = 0.03196 1/hours

pH:

7

Temp.:

29 °C

Hydrolysis rate constant:

0.01 h-1

DT50:

92 h

Type:

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

Remarks on result:

other: rate constant = 0.00747 1/hours

Validity criteria fulfilled:

yes

Conclusions:

T002102 was found to be hydrolytically stable at pH 4.0 with an estimated half-life time of about 200 days at 50°C, therefore no further testing was performed. T002102 was not stable at pH 7.0 and additional testing determined a half-life time of 187 hours (8 days) at 25°C. T002102 was found to be very unstable at pH 9.0 at 50°C, therefore no further testing was performed. The half-life time of T002102 at pH 9.0 is less than one day at 25°C.

Description of key information

One study (Peither, 2002) is included in this dossier and regarded as a key study (Klimisch score of 1).  A half-life time of 187 hours at 25 °C and pH 7 was determined for T002102.

Key value for chemical safety assessment

Half-life for hydrolysis:

187 h

at the temperature of:

25 °C

Additional information

One study on the hydrolysis of T002102 was included in this dossier (Peither, 2002). T002102 was found to be hydrolytically stable at pH 4.0 with an estimated half-life time from about 200 days at 50 °C, therefore no further testing was performed. T002102 was not stable at pH 7.0 and additional testing determined a half-life time of 187 hours at 25 °C. T002102 was found to be very unstable at pH 9.0 at 50 °C, therefore no further testing was performed. The half-life time of T002102 at pH 9.0 is less than one day at 25 °C.