Hexan-4-olide

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

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)

GLP compliance:

yes

Specific details on test material used for the study:

Test substance: Gamma-Dodecanolactone
Chemical name (IUPAC): Dihydro-5-octylfuran-2(3H)-one (1)
CAS RN: 2305-05-7 (1)
Molecular mass (a.i.): 198.3 g·mol-1 (1)
Molecular formula (a.i.): C12H22O2 (1)
Structural formula (a.i.): (1)
Received on: 08/Nov/2017
Bioagri Laboratórios Ltda. code: AGR-0830/17
Declared concentration (a.i.): 99.02% (w/w) (1)
Analyzed concentration (a.i.) (Bioagri Laboratórios Ltda.): 99.01% (w/w)
Certificate of Analysis (CoA): CA TH - 0314/17 (homogeneous sample)
Batch nº: 050170905
Test item sent by: Anhui Hyea Aromas Co., Ltd.
Physical state: Colorless liquid (1)
Water solubility (a.i.): 0.06 g·L-1 (1)
Manufacturing date: 19/Sep/2017 (1)
Expiry date: 18/Sep/2018 (1)
Manufacturer: Anhui Hyea Aromas Co., Ltd.
Address of manufacturer: Pengling Industrial Area, Qianshan County Anhui Province, China.

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

A stock solution was prepared by adding 60.60 mg of AGR-0830/17 (purity: 99.01%) in a 10 mL volumetric flask and completed with methanol (SS-A). Taking the mass concentration of the active ingredient, the calculated concentration in this stock solution was 6.00 mg·L-1. An aliquot of 1 mL of this solution was withdrawn, added to a 100 mL volumetric flask and completed with ultrapure water (SS-B).

Buffers:

pHs 4, 7, 9 and 10 sterilized buffers (buffer solution of pH 10 was used only for calibration of pHmeter);
Ultrapure water (sterilized);
Acetic acid - Purity: 100%;
Acetonitrile HPLC grade - Purity: 99.9%;
Methanol HPLC grade - Purity: 99.9%;
TSA - Tryptone Soya Agar;
SAB - Sabouraud Dextrose Agar.

Details on test conditions:

A preliminary test was performed at 50.0 +- 0.5°C at pHs 4, 7 and 9 in order to determine the hydrolytic stability of the test substance under these conditions.

Duration:

5 d

pH:

4

Temp.:

50 °C

Initial conc. measured:

ca. 0.6 mg/L

Duration:

5 d

pH:

7

Temp.:

50 °C

Initial conc. measured:

ca. 0.6 mg/L

Duration:

5 d

pH:

9

Temp.:

50 °C

Initial conc. measured:

ca. 0.6 mg/L

Number of replicates:

2

Positive controls:

no

Negative controls:

no

Preliminary study:

The concentrations of the test substance in the solutions prepared for the preliminary test were determined by the LC-MS method described in section 7.1. The analytical method was calibrated by a set of solutions prepared from the analytical standard. The representative chromatogram of the analytical standard is shown in Figure 2.

All sets of calibration data were prepared using the analytical standard at concentrations above and below the nominal concentration and showed excellent linear correlations between the active ingredient concentration and the peak area of the chromatograms. The correlation coefficient for the calibration curve was 0.99 (Figure 1). Thus, the LC-MS method described in section 7.1. was suitable for this study.

Representative chromatograms of the buffers solutions without application of the test substance are showed in Figure 3 for pH 4, Figure 4 for pH 7 and Figure 5 for pH 9.

The results of the initial concentration determination, and those performed after 5 days of incubation at 50 ± 0.5oC are presented in Table 3. Figure 6 show a graphic with the variation of temperature during the incubation period. The results of the preliminary test showed that the test substance concentration decreased at pH 7 and 9, indicating that the test substance is stable at pH 4, but unstable at pHs 7 and 9. Figures 7 and 8 show the chromatograms obtained for pH 4, Figures 9 and 10 show the chromatograms obtained for pH 7, Figures 11 and 12 the chromatograms obtained for pH 9.

Transformation products:

not measured

Key result

pH:

4

Temp.:

50 °C

Remarks on result:

hydrolytically stable based on preliminary test

Remarks:

The test substance in function of pH is considered stable for a half-life period exceeding one year (t1/2 > 1 year) at pH 4. For pHs 7 and 9 a definitive test (Tier II) is required to determine the half-life of the test substance.

Details on results:

According to the results of Tier I, the test substance (Gamma-Dodecanolactone) did not degrade more than 10% of the initial concentration at 50 ± 0.5°C at pH 4, but at pHs 7 and 9 the concentration of the test substance decreased from the initial concentration. The test substance in function of pH is considered stable for a half-life period exceeding one year (t1/2 > 1 year) at pH 4. For pHs 7 and 9 a definitive test (Tier II) is required to determine the half-life of the test substance.

Table 2 - Concentrations used in the calibration curve.

 

Calibration solution	Solution used for preparation	Volume taken in the preparation of the solution (mL)	The total volume of solution (mL)	(mg·L^-1)
A^(a)	-	-	10.00^(b)	975.80
B	A	0.082	2.00	40.01
C	B	0.500	1.00	20.01
D	B	0.075	1.00	3.00
E	B	0.025	1.00	1.00
F	B	0.002	1.00	0.08

 ^(a)Data not used in the calibration curve.                                       

^(b)The preparation of SS-C is described in section 6.7.3.

Table 3 - Concentration of the test substance in the buffer solutions as a function of pH at 50^oC (preliminary test).

 

Incubation Time (days)	Buffer pH	4	7	9
0	Test solution pH	3.99	7.00	9.01
	Analysis 1	17.86	20.47	36.29
	Analysis 2	18.24	20.18	36.28
	c1 mg·L^-1)	18.05	20.32	36.29
	Analysis 1	18.46	20.35	36.03
	Analysis 2	18.58	20.17	35.82
	c2(mg·L^-1)	18.52	20.26	35.92
	Caverage(mg·L^-1)	18.28	20.29	36.10
5	Analysis 1	*	15.34	0.69
	Analysis 2	18.89	15.29	0.44
	c1 (mg·L^-1)	18.89	15.31	0.57
	Analysis 1	19.60	15.66	0.46
	Analysis 2	19.97	15.27	0.30
	c2(mg·L^-1)	19.78	15.46	0.38
	Caverage(mg·L^-1)	19.34	15.39	0.47
	D^[a](%)	0.00	24.16	98.69

 [a]        Variation after 5 days of incubation at 50±0.5°C, calculated from the average concentrations obtained at times 0 and 5 days (see equation [2]).

* Analytical error.

Table 4 - Microbiological analysis.

 

Samples	Incubation Temperature  (^oC)	Incubation Time (days)	Results
TSA Plate (bacterial count)	32.5	3	< 1.0 CFU · time^-1
SAB Plate (count of yeasts and molds)	22.5	7	< 1.0 CFU · time^-1

 

Table 5 - Composition of buffered solutions used in the study.

 

Buffer solution	Composition	Buffer
pH 4	Citric acid, sodium hydroxideand hydrogen chloride.	Citrate buffer
pH 7	Disodium hydrogen phosphate and potassium dihydrogen phosphate.	Phosphate buffer
pH 9	Boric acid, potassium chlorideand sodium hydroxide.	Borate buffer
pH 10	Boric acid, potassium chlorideand sodium hydroxide.	Borate buffer

 

 

 

 

Description of key information

The test substance in function of pH is considered stable for a half-life period exceeding one year (t1/2 > 1 year) at pH 4. For pHs 7 and 9 a definitive test (Tier II) is required to determine the half-life of the test substance.