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Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study is well documented and well performed, according to OECD and GLP guidelines
Qualifier:
according to guideline
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
Qualifier:
according to guideline
Guideline:
EU Method C.7 (Degradation: Abiotic Degradation: Hydrolysis as a Function of pH)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 835.2110 (Hydrolysis as a Function of pH)
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
- Sampling intervals for the parent/transformation products: hydrolysis samples were collected from each pH after the test solution was placed into the test vessels (0h) and at 2h, 5h, 1d and 5days.
- Sample processing: at each sampling interval for each buffer test system, duplicate samples were taken and analyzed by HPLC.
- Sampling intervals/times for pH measurements: the pH of the buffer solutions were measured after preparation and sterile filtration. The pH was also documented after sample fortification of pH 4, 7 and 9 buffer test solution on day 0 and day 5.
- Sampling intervals/times for sterility check: sterility was determined at day 0 for sterile pH 4, 7 and 9 buffer test systems and at day 5 for pH 4, 7 and 9 buffer test systems.
Buffers:
STERILE PH4 BUFFER
- pH: 4
- Type and final molarity of buffer: 0.01M
- Composition of buffer: buffer was prepared by combining 410 ml of 0.01 M acetic acid solution with 90 ml of 0.01 M sodium acetate solution. Final pH adjustments were made with sodium hydroxide as necessary. The pH of the buffer solution was verified (4.04) following sterilization.
1/ a 0.01M acetic acid solution was prepared by adding 0.288 ml of glacial acetic acid to a 500 ml volumetric flask and diluting to volume with deionized water
2/ a 0.01M sodium acetate solution was prepared by adding 0.410 g sodium acetate to a 500 ml volumetric flask and diluting to volume with deionized water


STERILE PH7 BUFFER
- pH: 7
- Type and final molarity of buffer: 0.02M
- Composition of buffer: buffer was prepared by adding 195 ml of 0.01 M acetic acid solution with 90 ml of 0.01 M sodium phosphate monobasic and 305 ml of 0.02 M sodium phosphate dibasic to a 1000 ml volumetric flask. The contents were diluted with deionized water, to produce a 0.01 M pH 7.0 phosphate buffer solution. Final pH adjustments were made with sodium hydroxide. The pH of the buffer solution was verified (7.08) following sterilization.
1/ a 0.02 M sodium phosphate monobasic solution was prepared by adding approx 1.56 g of sodium phosphate monobasic (dihydrate) to a 500 ml volumetric flask and diluting to volume with deionized water.
2/ a 0.02 M sodium phosphate dibasic solution was prepared by adding approx 1.42 g sodium phosphate dibasic (anhydrous) to a 500 ml volumetric flask and diluting to volume with deionized water.


STERILE PH 9 BUFFER
- pH 9
- Type and final molarity of buffer: 0.5M
- Composition of buffer: A 0.5M boric acid solution was prepared by transferring 30.9 g of boric acid (61.83 g/mole) to a 1000 ml volumetric flask and diluting to volume with deionized water. A 20 ml sample of the 0.5M boric acid solution was transferred to a 1000 ml volumetric flask and diluted to volume with deionized water. This 0.01M boric acid solution was adjusted to pH 9 with 50% (w/w) sodium hydroxide solution to produce a 0.01 M pH 9.0 borate buffer solution. the pH of the buffer solution was 9.04 following sterilization.
Details on test conditions:
EXPERIMENTAL APPARATUS
- Individual test systems were composed of sterile buffer containing the test material in separate amber glass vessels with screw caps. The individual hydrolysis test vessels were placed in thermostatically temperature controlled chambers at 50 +/- 0.5°C for preliminary tests and the details of the experimental designed were listed.
- Each test system was sterilized at a minimum of 121°C and 15 lbs/inche² for 20 minutes prior to use in this study.


TEST SYSTEM (PRELIMINARY TEST)
- Test duration: 5d
- Test system: sterile pH 4, 7 and 9 buffers
- Test concentration: approx 5 mg/L
- No of reps: 2 replicates per test system
- Test apparatus: 5 ml amber vials. Test material dispensed into test vessels with the sterile buffer
- Traps for CO2 and organic volatiles: none
- Identity of solvent: nil
- Volume of test solution used for treatment: 1 ml/100 ml sterile pH 4, 7 and or 9 buffer
- Application method: pipette
- Evaporation of application solvent: not applicable
- Experimental conditions, temperature: 50 +/- 0.5°C
- Sampling intervals: duplicate samples per test system according to the following schedules. Immediately after the test material was placed into the test vessels 0, 2, 5h, 1d, 5d
- Sample storage before analysis: samples were analyzed on the sampling day
-The hydrolysis test vials were capped, wrapped in aluminium foil and stored in a dark thermostatically temperature controlled chamber
- Sterilisation method: Sterility measurements were checked by serial dilution plate techniques. Agar plates (nutrient agar for bacteria) were used to determine sterility of buffer test systems. One ml of each buffer test system were serially diluted up to 10^-4 dilutions. From 10^-6 to 10^-9 dilutions, one ml of diluted sample was aseptically transferred to labeled agar plates. Four replications were maintained for each dilution. The control agar plates (devoid of buffer test system) were maintained as standard check. After inoculation, all the agar plates were incubated in a BOD incubator 2 days at 35 +/- 2°C. After incubation, all the agar plates were carefully examined for determining bacterial growth as compared to control agar plates.


TEST MEDIUM
- Volume used/treatment: A 4.0 ml aliquot of the test solution was transferred into individual test vials
- Preparation of stock solution: N-n-Butylbenzenesulphonamide (Proviplast 024) solution was prepared in acetonitrile (50 ml). The stock solution was fortification was prepared by diluting BBSA solution with milli-Q water. The stock solution was analyzed by HPLC to determine chemical purity of the test item. The concentration of the BBSA (Proviplast 024) stock solution was approx 500 mg/L
- Preparation of test solution: test solutions were prepared by dilution of the stock solution with filter-sterilized buffer solution to obtain a final concentration of approx 5 mg/L BBSA (Proviplast 024). The test solutions were prepared in a dark room. For each buffer the test solution was prepared in a sterile glass bottle by mixing 100 ml of buffer with 1 ml of BBSA (proviplast 024) stock solution.

Duration:
5 d
Initial conc. measured:
4.9 mg/L
Number of replicates:
- 10 vials were prepared for each pH 4, 7 and 9 buffer
- 2 replicates per test system
Positive controls:
not specified
Negative controls:
not specified
Preliminary study:
pH 4: >90% of the recovered test item compared to the 0h analysis
pH 7: >90% of the recovered test item compared to the 0h analysis
pH 9: >90% of the recovered test item compared to the 0h analysis
BBSA was hydrolytically stable at Ph4, 7 and 9 based on the preliminary result. So definitive study was not conducted
Transformation products:
no
Remarks:
no transformation products exist as the substance was stable under the experimental conditions.
% Recovery:
> 90
pH:
4
Temp.:
50 °C
Duration:
5 d
% Recovery:
> 90
pH:
7
Temp.:
50 °C
Duration:
5 d
% Recovery:
> 90
pH:
9
Temp.:
50 °C
Duration:
5 d
Key result
Temp.:
50 °C
Hydrolysis rate constant:
ca. 0 min-1
Validity criteria fulfilled:
yes
Conclusions:
This study demonstrated that N-n-butylbenzenesulphonamide (Proviplast 024) was hydrolytically stable at pH 4, 7 and 9. Based on the results of this study, hydrolysis will not be a route of degradation of N-n-butylbenzenesulphonamide (Proviplast 024) in the environment.

Description of key information

> 90 % of BBSA is recovered in a standard hydrolysis test (OECD 111) in 5 days at 50°C and pH 4, 7 and 9. According to the test guidelines, this corresponds with an half-lif of > 1 year at  25°C.

The substance is hence not prone to hydrolysis.

Key value for chemical safety assessment

Half-life for hydrolysis:
1 yr
at the temperature of:
25 °C

Additional information