Dimethyldioctylammonium chloride

Hydrolysis

Link to relevant study record(s)

Reference

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 June to 27 August 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

A preliminary study was conducted to determine the approximate degradation rate and evaluate the test substance prior to defining the definitive test. The preliminary test was run using buffer solutions at pH 5, 7 and 9. At pH 7 both 'HEPES' and 'TRIS' buffers were tested. The nominal test concentration was 10 ug/mL Both silanised and non-silanised test vessels were used to evaluate adsorption. The test vessels were wrapped in foil to exclude light, placed on a mechanical shaker in an environmental chamber maintained at 25+/-1oC. Samples were taken after 0, 1, 4, 8, 21 and 96 hours for analysis by liquid scintillation counting (LSC) and thin-layer chromatography (TLC).

A 30-day hydrolysis study with C14 didecyldimethylammonium chloride was conducted at 25oC at pH 5, 7 and 9. All experiments were conducted at the nominal test concentration of 10 ug/mL under sterile conditions and in darkness. Samples were taken at 0, 4, 7, 14, 22 and 30 days and were quantified for test substance and hydrolysis products by liquid scintillation counting (LSC) and thin-layer chromatography (TLC).

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Supplied by Lonza Inc., batch/lot no. 7499-E
- Expiration date of the lot/batch: No data
- Purity test date: No data

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity:
- Specific activity: 5.49 x 10*7 dpm/mL
- Locations of the label: on an N-methyl group
- Expiration date of radiochemical substance: No data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
- Stability under test conditions:
- Solubility and stability of the test substance in the solvent/vehicle:
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

OTHER SPECIFICS:

Radiolabelling:

yes

Analytical monitoring:

yes

Details on sampling:

Preliminary study samples were taken after 0, 1, 4, 8, 21 and 96 hours
Definitive study samples were taken after 0, 4, 7, 14, 22 and 30 days
Duplicate aliquots from each sample were analysed by LSC and TLC.

Buffers:

- pH: 5
Addition of 59.2 mL 0.2M acetic acid to 140.8mL of 0.2M sodium acetate. The solution was dluted to 400mL in water

- pH: 7 (TRIS)
Addiition of 94mL of 0.2M hydrochliric acid to 100mL of 0.2M tris(hydroxymethyl)aminomethane. The solution was diluted to 400mL in water

- pH: 7 (HEPES)
Addition of 2.38g N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES) to 1000mL water (0.01M), then adding 2M potassium hydroxide until pH7 was achieved

- pH: 9
Addition of 100mL of 0.2M boric acid to 118mL of 0.2Mborax solution. The solution was diluted to 400mL with water.

All water used to prepare buffers was Millipore Milli-Q purified, filtered through 0.2um filter.

Preliminary study:

A preliminary test using pH 5, 7 and 9 buffers was conducted over 96 hours and indicated that DDAC was stable under the conditions of the test.

Transformation products:

not measured

pH:

5

Remarks on result:

hydrolytically stable based on preliminary test

pH:

7

Remarks on result:

hydrolytically stable based on preliminary test

pH:

9

Remarks on result:

hydrolytically stable based on preliminary test

Key result

pH:

5

Temp.:

30 °C

DT50:

>= 368 d

Type:

not specified

Key result

pH:

7

Temp.:

30 °C

DT50:

>= 175 d

Type:

not specified

Key result

pH:

9

Temp.:

30 °C

DT50:

>= 506 d

Type:

not specified

Preliminary test results

Sampling time (h)	pH 5 (preliminary test)
	Measured concn, non‑silanised (ug/mL)	Measured conc, silanised (ug/mL)	Mean measured conc (ug/mL)	% recovery of initial measured concn	TLC (% 14C as DDAC)
0	9.09	9.09	9.09	100	95.7
1	9.06	8.39	8.73	96	97.2
4	9.23	9.38	9.31	102	96.0
8	9.36	8.90	9.13	100	95.5
21	10.2	8.75	9.48	104	92.8
96	8.47	10.2	9.34	103	-

 

Sampling time (h)	pH 7 HEPES buffer (preliminary test)					pH 7 TRIS buffer (preliminary test)
	Measured concn, non‑silanised (ug/mL)	Measured conc, silanised (ug/mL)	Mean measured conc (ug/mL)	% recovery of initial measured concn	TLC (% 14C as DDAC)	Measured concn, non‑silanised (ug/mL)	Measured conc, silanised (ug/mL)	Mean measured conc (ug/mL)	% recovery of initial measured concn	TLC (% 14C as DDAC)
0	9.77	9.77	9.77	100	93.9	8.56	8.56	8.56	100	93.6
1	8.58	8.56	8.57	88	97.4	8.56	8.73	8.65	101	97.9
4	8.71	8.93	8.82	90	95.2	8.56	8.67	8.62	101	95.1
8	9.13	9.58	9.36	96	88.5	8.43	8.25	8.34	97	96.1
21	9.38	9.19	9.29	95	88.0	8.64	8.68	8.66	101	97.0
96	9.77	9.80	9.79	100	-	9.57	8.30	8.94	104	-

 

Sampling time (h)	pH 9 (preliminary test)
	Measured concn, non‑silanised (ug/mL)	Measured conc, silanised (ug/mL)	Mean measured conc (ug/mL)	% recovery of initial measured concn	TLC (% 14C as DDAC)
0	10.0	10.0	10.0	100	92.6
1	8.69	8.92	8.81	88	97.9
4	8.48	9.17	8.83	88	95.2
8	8.58	8.89	8.74	87	89.5
21	9.42	9.80	9.61	96	93.8
96	9.81	9.81	9.81	98	-

Definitive test results

Sample day	pH 5 (definitive test)
	Measured concn (ug/mL as DDAC)	% recovery of initial measured concn	TLC (% 14C as DDAC)	Mass balance (% of initial total activity)
0	7.98	100	92.8	100
4	8.26	104	92.7	104
7	8.23	103	92.0	104
14	7.98	100	92.8	100
22	8.13	102	95.9	98.6
30	7.56	94.8	92.0	95.6

 

Sample day	pH 5 HEPES buffer (definitive test)				pH 5 TRIS buffer (definitive test)
	Measured concn (ug/mL as DDAC)	% recovery of initial measured concn	TLC (% 14C as DDAC)	Mass balance (% of initial total activity)	Measured concn (ug/mL as DDAC)	% recovery of initial measured concn	TLC (% 14C as DDAC)	Mass balance (% of initial total activity)
0	7.98	100	94.2	100	8.33	100	95.9	100
4	8.47	106	93.9	106	8.32	99.9	93.5	102
7	7.89	98.9	92.4	101	8.09	97.1	93.1	100
14	7.90	99.0	94.5	98.7	8.30	99.6	95.8	100
22	7.45	93.4	94.0	93.6	7.67	92.0	97.9	90.1
30	7.45	93.4	89.9	97.9	7.52	90.3	94.5	91.6

 

Sample day	pH 9 (definitive test)
	Measured concn (ug/mL as DDAC)	% recovery of initial measured concn	TLC (% 14C as DDAC)	Mass balance (% of initial total activity)
0	8.28	100	95.5	100
4	7.88	95.2	92.0	98.8
7	7.80	94.2	93.5	96.2
14	8.12	98.0	95.7	97.8
22	7.74	93.4	96.7	92.3
30	7.80	94.1	94.6	95.0

Validity criteria fulfilled:

not specified

Conclusions:

A preliminary test using pH 5, 7 (HEPES & TRIS buffer) and 9 buffers over 96 hours indicated that DDAC was stable under the conditions of the test. It was also determined that the test substance did not adsorb to either silanised or non-silanised glass.
A definitive test using pH 5, 7 (HEPES & TRIS buffer) and 9 buffers over 30 days gave calculated half-lives of 368, 175, 194 and 506 days, respectively

Executive summary:

A hydrolysis study was conducted according to the principles of GLP but did not follow a specific test guideline. A preliminary test using pH 5, 7 and 9 buffers was conducted over 96 hours and indicated that DDAC was stable under the conditions of the test.

A definitive test using pH 5, 7 and 9 buffers was conducted over 30 days. Calculated half-lives of 368 (pH5), 175 (pH7), 194 (pH7) and 506 (pH9) days indicated the stability of the test substance to hydrolysis. TLC analysis demonstrated a decrease in C14 activity of less than 10% in the parent test substance.

The test substance is hydrolytically stable at pHs 5, 7 and 9 at 25oC under the conditions of the test.

Description of key information

There are no studies available for the determination of hydrolysis of the substance. However, there is a reliable study (Klimisch 2) available for the read-across substance, didecyldimethyl ammonium chloride (DDAC). A definitive test was conducted over 30 days at pH 5, 7 and 9. The calculated half-lives were all greater than 175 days indicating the test substance was hydrolytically stable under the conditions of the test. Supporting thin-layer chromatography (TLC) analysis indicated less than 10% decrease in C14 activity in the parent test substance. This study was conducted according to the principles of GLP but did not follow a specific test guideline.

Key value for chemical safety assessment

Half-life for hydrolysis:

175 d

at the temperature of:

25 °C