β,β-carotene

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 2005-09-22 to 2005-11-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline-conform study performed under GLP without deviations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

column elution method

Test material

Test material information

Constituent 1

Reference substance name:

β,β-carotene

EC Number:

230-636-6

EC Name:

β,β-carotene

Cas Number:

7235-40-7

Molecular formula:

C40H56

IUPAC Name:

β,β-carotene

Details on test material:

- Name of test material (as cited in study report): ß-Carotene crystalline
- Physical state: crystalline solid
- Analytical purity: 97.77%
- Lot/batch No.: WC00504271
- Expiration date of the lot/batch: July 2007 (in an unopened ampoule)
- Stability under test conditions: Light-sensitive
- Storage condition of test material: At room temperature in the unopened ampoule; in the freezer under argon when not stored in the ampoule. As the test item is light-sensitive, all test item handling was performed under red light.

Results and discussion

Water solubility

Water solubility:

< 0.015 mg/L

Temp.:

20 °C

pH:

ca. 7

Details on results:

The amount of test item in the samples, if any, was below the smallest calibration point with 0.1536 µg/mL.

During the test six samples in the first run (0.52 I/min) and six samples during the second run (0.26 I/min), each with a sampling interval of one hour were analyzed. Total elution time was 96.5 hours. The samples were measured after lyophilization and re-dissolving in hexane using an HPLC-system for the quantification.
The amount of test item in the samples, if any, was below the smallest calibration point with 0.1536 μg/ml, taking the concentration factor of 10 through lyophilization into consideration, the water solubility was calculated to be < 0.0154 μg/ml.

The r2 fit was 1.0000 (optimum). This reflects the linearity of the HPLC-system within the calibration range of 0.1536 μg/ml to 15.36 μg/ml of the test item.

Any other information on results incl. tables

Injected samples were quantified by peak area with reference to the calibration curve. The latter obtained by correlation of the peak area of the test item solutions with their corresponding concentration. The correlation was performed using at least squares fit of the function given below.

From this curve the concentration x of beta-carotene cryst. in the injected solutions was calculated by the following equation:

Y = b * x + a x = (Y - a) / b C = f * x

where Y = peak area of injected sample solutions; x = concentration of injected sample solution [ug/ml]; b = slope ; a = y-axis intercept; f = factor for dilution; C = concentration of the test item after saturation [ug/ml]

Results of water solubility of beta-carotene:

Experiment no.	flow rate [ml/]	sample no.	concentration analyzed [ug/ml]	water solubility calculated [mg/l]		pH
1	31	1	< 0.1536	< 0.015	<  0.015	6.52
		2	< 0.1536	< 0.015		6.56
		3	< 0.1536	< 0.015		6.49
		4	< 0.1536	< 0.015		6.45
		5	< 0.1536	< 0.015		6.83
		6	<   0.1536	<  0.015		6.48
2	16	7	< 0.1536	< 0.015		6.73
		8	< 0.1536	< 0.015		6.76
		9	< 0.1536	< 0.015		6.74
		10	< 0.1536	< 0.015		6.59
		11	<  0.1536	< 0.015		6.93
		12	< 0.1536	< 0.015		6.96

Applicant's summary and conclusion

Conclusions:

Interpretation of results: insoluble (< 0.1 mg/L) <0.015 mg/L
The water solubility was determined to be <0.015 mg/L at 20 °C.

Executive summary:

The determination of the water solubility of beta-Carotene cryst. was performed according to the EEC Directive 92/69, A.6 "Water Solubility" (1992) and the OECD guideline No. 105, "Water Solubility" (adopted July 27, 1995), using the column elution method.

During the test six samples in the first run (0.52 l/min) and six samples during the second run (0.26 l/min), each with a sampling interval of one hour were analyzed. Total elution time was 96.5 hours. The samples were measured after lyophilization and re-dissolving in hexane using an HPLC-system for the quantification. The amount of test item in the samples, if any, was below the smallest calibration point with 0.1536 ug/ml, taking the concentration factor of 10 through lyophilization into consideration, the water solubility was calculated to be < 0.0154 ug/ml.

The calibration tests are reflecting the linearity of the used HPLC-system withhin the calibration range of 0.1536 ug/ml and 15.36 ug/ml.

In conclution, the water solubility of beta-Carotene crystalline at 20 °C was determined to be < 0.015 mg/l using the clumn elution method.

The water solubility was not corrected for the purity of the test item.