Sodium hydrogen L-aspartate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24.08.2017 to 29.08.2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Principles of method if other than guideline:

Test Temperature: 20 ± 1 °C

Apparatus

HPLC system: Merck-Hitachi LaChrom
HPLC Conditions
Detector: UV, 205 nm
Column: Acclaim® Trinity™ P1, 100x3 mm; 3 µm
Injection volume: 20 µL
Mobile Phase: Acetonitrile: Buffer Solution = 10 : 90
Flow rate: 0.4 mL/minutes
Retention time: 4 minutes
Run time: 9 minutes

Ultrapure water: ASTM Type 1, Prepared by Direct-Q5 system, Millipore
Acetonitrile: for HPLC, VWR, Lot No.: 17C161343, Expiry Date: March 2020

Analysis of Samples
The saturated samples were centrifuged at 20 °C, at 4000 rpm (5 min) and the concentration in the clear aqueous phase was determined by HPLC. The samples were diluted with mobile phase before HPLC measuring. The test item was measured using the previously validated reverse phase HPLC method with UV detection.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

631.68 g/L

Conc. based on:

test mat.

Incubation duration:

24 h

Temp.:

20 °C

pH:

7

Table 4. Results of the determination of water solubility of L-aspartic acid sodium salt monohydrate
Sampling time	Measured concentrationofTest Item (g/L )		Measured pH
	Test vessels	Mean
After 24h	632.42	628.77	7.16
	626.56		7.15
	627.34		7.16
After 48h	640.03	632.76	7.18
	625.04		7.17
	633.22		7.17
After 72h	628.47	633.51	7.19
	638.66		7.17
	633.39		7.18
Solubility ofthe test item (g/L):		631.68 ± 6.32	-
RSD%:		0.4	-

 

The repeatability of the determination was < 15% and thus within the range required by the guidelines.

Conclusions:

The water solubility of the test item was determined to be 631.7 ± 6.32 g/L (95% confidence interval) at 20 °C ± 0.5 °C and pH 7 using the shake-flask method for the performance of the main test. The result is also applicable for the water free form of the test item.

Executive summary:

The water solubility was determined according to OECD 105 and regulation (EC) No 440/2008 method A.6 using the shake flask method with HPLC analysis. About 27.75 g test item were weighed into stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 10 mL ultrapure water, the flasks were agitated at 30 °C. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The pH of each sample was recorded. The water solubility of the test substance was determined to be 631.68 ± 6.32 g/L (95 % confidence interval) at 20 °C ± 1 °C (pH 7.2). The result is also applicable for the water free form of the test item.

Description of key information

The water solubility of the test item was determined to be 631.7 ± 6.32 g/L (95% confidence interval) at 20 °C ± 0.5 °C and pH 7 using the shake-flask method for the performance of the main test. The result is also applicable for the water free form of the test item.

Key value for chemical safety assessment

Water solubility:

631.7 g/L

at the temperature of:

20 °C

Additional information

The water solubility was determined according to OECD 105 and regulation (EC) No 440/2008 method A.6 using the shake flask method with HPLC analysis (reference 4.8 -1). About 27.75 g test item were weighed into stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 10 mL ultrapure water, the flasks were agitated at 30 °C. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The pH of each sample was recorded. The water solubility of the test substance was determined to be 631.68 ± 6.32 g/L (95 % confidence interval) at 20 °C ± 1 °C (pH 7.2). The result is also applicable for the water free form of the test item.