Storax (balsam)

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Jul 2017-06 Nov 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

GLP compliance:

yes

Type of method:

other: slow-stirring flask method

Remarks:

In the preliminary test the water solubility of the test item was < 10-2 g/L. Based on the results of the preliminary test the slow-stirring flask method was chosen for the main study.

Test material

Test material information

Constituent 1

Reference substance name:

Storax (balsam)

EC Number:

232-458-4

EC Name:

Storax (balsam)

Cas Number:

8046-19-3

Molecular formula:

Not applicable, UVCB - NCS

IUPAC Name:

Storax (balsam)

Test material form:

other: liquid

Details on test material:

CAS : 8046-19-3 EINECS : 232-458-4
- Name of test material (as cited in study report): STYRAX RESINOID OIL
- Test Facility test item number: 208399/A
- Appearance: Orange viscous liquid
- Substance type: pure substance
- Physical state: liquid
- Analytical purity: 100%

Results and discussion

Water solubility

Water solubility 1

Key result

Water solubility:

0.268 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

1 mg/L

Temp.:

20 °C

pH:

>= 5.9 - <= 6

Water solubility 2

Key result

Water solubility:

1.25 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

10 mg/L

Temp.:

20 °C

pH:

>= 6.1 - <= 6.2

Water solubility 3

Key result

Water solubility:

8.02 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

100 mg/L

Temp.:

20 °C

pH:

>= 5.5 - <= 7.2

Details on results:

A small response at the retention time of the test item was detected in the chromatogram of the blank water mixture. It was considered to derive from carry-over in the analytical system since similar responses were found in the analytical blanks.
Main Study – loading 1 mg/L
The results for the samples taken at 24, 48 and 72 hours are given in Table 7.
The 24-hour measurement was significantly lower than the 48- and 72- hour measurements (maximum difference > 15%). Based on this, the water solubility of the test item was given as the mean value of the 48- and 72-hour measurements. At a loading rate of 1 mg/L 26.8% of the applied test-item loading was dissolved. Please see below Table 7.

Main Study – loading 10 mg/L
The results for the samples taken at 24, 48 and 72 hours are given in Table 8.
The maximum difference of the concentrations determined in the 24, 48 and 72 hour test samples was ≤ 15%. Based on this, the water solubility of the test item is given as the mean value of the analyzed concentrations. At a loading rate of 10 mg/L 12.5% of the applied test-item loading was dissolved. Please see below Table 8.

Main Study – loading 100 mg/L
The results for the samples taken at 24, 48 and 72 hours are given in Table 9. The maximum difference of the concentrations determined in the 24, 48 and 72 hour test samples was ≥ 15%: the sample stirred for 48 hours significantly deviated from the concentrations observed in the samples stirred for 24 and 72 hours. Please see below Table 9.

Based on this, these water solubility vessels were sampled again after 24 hours of additional stirring. The results for the samples taken at 48, 72 and 96 hours are given in Table 10. Please see below Table 10.

The maximum difference of the concentrations determined in the 48, 72 and 96 hour test samples was again ≥ 15%. A very similar set of results was obtained as after 24, 48 and 72 hours. The trend that the intermediate stirring time gave the lowest concentration remained. The same vessel of intermediate stirring time (first 24 h, then 48 h) contained significantly less dissolved test item than the other two samples. The value did not agree with what was observed in initial analysis after 48 hours of stirring. The variation in water solubility was, therefore, not a time-dependent phenomenon.
It rather seemed typical for this test item that water solubility varied more at higher loading rates. Therefore, the result of the water solubility at loading rate 100 mg/L was to calculate based on all analytical results: 8.02 mg/L. At a loading rate of 100 mg/L 8.02% of the applied test-item loading was dissolved.

Any other information on results incl. tables

Table 7          
Water Solubility of the Test Item at loading rate 1 mg/

Stirring time [hours]	Analyzed concentration [mg/L]	Mean [mg/L]	Maximum difference [%]	pH
24	0.160	0.268	4.2	5.9
48	0.262			6.0
72	0.273			6.0

Table 8          
Water Solubility of the Test Item at loading rate 10 mg/L

Stirring time [hours]	Analyzed concentration [mg/L]	Mean [mg/L]	Maximum difference [%]	pH
24	1.32	1.25	12	6.1
48	1.17			6.2
72	1.25			6.1

Table 9          
Water Solubility of the Test Item at loading rate 100 mg/L

Stirring time [hours]	Analyzed concentration [mg/L]	Mean [mg/L]	Maximum difference [%]	pH
24	9.56	7.38	86	5.9
48	3.81			7.0
72	8.77			7.2

Table 10        
Water Solubility of the Test Item at loading rate 100 mg/L

Stirring time [hours]	Analyzed concentration [mg/L]	Mean [mg/L]	Maximum difference [%]	pH
48	11.4	8.67	82	6.3
72	4.76			6.1
96	9.84			5.5

Applicant's summary and conclusion

Conclusions:

The slow-stirring flask method was applied for the determination of the water solubility of Styrax resinoid oil. Based on the obtained results it was concluded that the water solubility of the test item in absolute concentrations increased with increasing loading. Expressing the water solubility as a percentage of the applied loading, it decreased with increasing loading. Especially at high loading, the water solubility for replicate samples varied significantly.

The water solubility of the test item at 3 loading rates at 20°C was given in the Water Solubility Key Results section.

Executive summary:

The water solubility of Styrax resinoid oil was experimentally measured and determined based on the slow-stirring flask method and an ultra performance liquid chromatographic method with spectrophotometric detection (UPLC-UV) according to the following guidelines:

EC Guideline A.6, OECD Guideline 105, OPPTS 830.7840: Water Solubility: Column Elution Method; Shake Flask Method. March 1998.

The water solubility of Styrax resinoid oil at 3 loading rates at 20°C is as follows:

Loading Rate [mg/L]		Concentration water solubility [mg/L]		pH
1		0.268		5.9 - 6.0
10		1.25		6.1 - 6.2
100		8.02		5.5 - 7.2