4,6-bis(octylthiomethyl)-o-cresol

Hydrolysis

Administrative data

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 January 2011 to 26 January 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to EU & OECD test guidance in compliance with GLP and reported with a valid GLP certificate

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 111 (Hydrolysis as a Function of pH)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4,6-bis(octylthiomethyl)-o-cresol

EC Number:

402-860-6

EC Name:

4,6-bis(octylthiomethyl)-o-cresol

Cas Number:

110553-27-0

Molecular formula:

C25H44OS2

IUPAC Name:

4,6-bis(octylthiomethyl)-o-cresol

Details on test material:

Name: THANOX 1520
Batch No.: 031006013
Purity: 99.7 %
Description: pale yellow to colourless liquid
Manufacture date: 25 June 2010
Expiry date: 25 June 2011
Manufacturer: Rianlon Chemical Co. Ltd.
Storage: room temperature, protect from light and humidity, under N2

The test item and safety instructions, required for the handling and disposal of the test substance, were received from the Sponsor.
Identification of THANOX 1520 was carried out by Central Dispensary Unit of LAB Research Ltd. and was based on its appearance and colour.

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
No data

Radiolabelling:

no

Study design

Analytical monitoring:

not required

Details on sampling:

Sampling: The reaction solutions were analysed at the start of the test and after five days with five replicate samples each.

Buffers:

pH: Hydrolysis was examined at three different pH values: 4.0, 7.0 and 9.0 in the dark. Buffer solutions:
pH 4.0: 2 ml 0.2 M Sodium hydroxide and 250 ml 0.2 M Potassium hydrogen phthalate will be diluted to 1000 ml with ultra-pure water
pH 7.0: 147.8 ml 0.2 M Sodium hydroxide and 250 ml 0.2 M Potassium dihydrogen phosphate will be diluted to 1000 ml with ultra-pure water
pH 9.0: 107.0 ml 0.2 M Sodium hydroxide and 250 ml 0.2 M Boric acid and Potassium chloride will be diluted to 1000 ml with ultra-pure water.

These sterile buffer solutions were prepared using reagent grade chemicals and ultra-pure, sterile water.
The pH of each buffer solution was checked with a calibrated pH meter.

Estimation method (if used):

No data

Details on test conditions:

APPARATUS
HPLC: Thermo-Finnigan Surveyor MS Pump, Serial No.: 54075
Thermo-Finnigan Surveyor Autosampler, Serial No.: 55097
Thermo-Finnigan Surveyor PDA Detector, Serial No.: 56138
Balances: BP221S Sartorius, No.: 11809117
L2200P Sartorius, No.: 38100037
Thermostat: LP 132, No.: 870595
pH meter: Mettler Toledo SevenEasy S20, No.: 1231025119
Water purification system: MILLIPORE, DIRECT Q3, FOMNO 7334I
Ultrasonic bath: Elmasonic S300H, ELMA, No.: 010890105
Refrigerator: Zanussi, No.: ZLKI-262
Magnetic Stirrer: Heoidolph, No.: 5041000000
Hot Air Steriliser:ATP line FED, WTB Binder, No.: 9110-0035

HPLC Conditions:
Column: Zorbax Eclipse XDB-C18 150 x 4.6 mm, 5um No.: USKH019457
Mobil Phase: Methanol
Flow: 1.0 ml/min.
Injection volume: 10 μl
Temperature: 25 °C
Detector: UV at 220 nm
Retention time:5.0 min ± 0.5 min

TEST CONDITIONS
Test temperature: 50 ± 0.5 °C
Light: The hydrolysis reaction was carried out using a dark thermostat to avoid photolytic effects.
Oxygen: Nitrogen was bubbled into the water for five minutes before the preparation of the solutions in order to exclude oxygen.

PERFORMANCE OF THE TEST
Test solutions: 500 ml sterile solutions were prepared. The pH of each buffer solution was checked with a calibrated pH meter.
Storage of the solutions: Solutions were transferred into 25 ml screw cap tubes. From each test solution eight tubes were prepared. The tubes were thermostated at 50 °C ± 0.5 °C.
Sampling: The reaction solutions were analysed at the start of the test and after five days with five replicate samples each.
Analysis of the samples: Samples were diluted with MeOH, then they were analysed with the above presented HPLC method.

Duration of test

Duration:

5 d

Temp.:

50

Number of replicates:

five replicate samples each.

Positive controls:

no

Negative controls:

no

Statistical methods:

Evaluation: The chromatograms were evaluated with the help of "Xcalibur". Calculations were carried out using "EXCEL for Windows".

Results and discussion

Preliminary study:

In the course of the preliminary test at pH 7 the initial concentration was lower than quantitatioin limit therefore the hydrolysis of THANOX 1520 could not be measured.

Significant decomposition was observed at pH 4 and 9; 27 and less than 44 % of the original concentration was measured. Hence the higher tier test should be performed at these pH values.

Test performance:

Significant decomposition was observed at pH 4 and 9; 27 and less than 44 % of the original concentration was measured. Hence the higher tier test should be performed at these pH values.

Transformation products:

not measured

Details on hydrolysis and appearance of transformation product(s):

Not assessed.

Details on results:

In the course of the preliminary test at pH 7 the initial concentration was lower than quantitation limit therefore the hydrolysis of THANOX 1520 could not be measured.

Significant decomposition was observed at pH 4 and 9; 27 and less than 44 % of the original concentration was measured. Hence the higher tier test should be performed at these pH values.

Any other information on results incl. tables

Measured data

pH	Sampling time, hour	Concentration of Test Item, μg/ml			Measured pH
		Results of the separate test vessels	Mean with the 95% confidence intervals	End/Start, %
4	0 (Start)	Control buffer		-	4.05
		0.520	0.546 ± 0.031	-	4.06
		0.545
		0.586
		0.548
		0.529
	120	Control buffer		-	4.01
		0.131	0.147 ± 0.053	27	4.00
		0.127
		0.119
		0.222
		0.137
7	0 (Start)	Control buffer		-	7.01
		-	BQL	-	7.05
		-
		-
		-
		-
	120	Control buffer		-	7.01
		-	BQL	-	6.96
		-
		-
		-
		-
9	0 (Start)	Control buffer		-	9.03
		0.229	0.281 ± 0.07	-	9.05
		0.263
		0.355
		0.331
		0.225
	120	Control buffer		-	9.02
		-	BQL	Less than 44%	8.92
		-
		-
		-
		-

BQL; Below quantitation limit

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In the course of the preliminary test at pH 7 the initial concentration was lower than quantitatioin limit therefore the hydrolysis of THANOX 1520 could not be measured.

Significant decomposition was observed at pH 4 and 9; 27 and less than 44 % of the original concentration was measured. Hence the higher tier test should be performed at these pH values.

Executive summary:

This study has been performed in accordance with the study plan, the Organisation for Economic Co-operation and Development (OECD), OECD Guidelines for Testing of Chemicals, Guideline No. 111, "Hydrolysis as a Function of pH", adopted 13 April 2004, Commission Regulation (EC) No 440/2008, Part C, C.7 "Degradation: Abiotic Degradation: Hydrolysis as a Function of pH", Official Journal of the European Union L 142 of 31 May 2008 and the Principles of Good Laboratory Practice (GLP) and reported with a valid GLP certificate.

 

In the course of the preliminary test at pH 7 the initial concentration was lower than quantitation limit therefore the hydrolysis of THANOX 1520 could not be measured.

 

Significant decomposition was observed at pH 4 and 9; 27 and less than 44 % of the original concentration was measured. Hence the higher tier test should be performed at these pH values.

 

Summary of the results of the preliminary test:

pH 7:     Concentration was below the quantitation limit

pH 4 and 9:  Significant decomposition was observed.