Dilanthanum tricarbonate

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 Dec 2005 - 21 Apr 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline

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

GLP compliance:

yes (incl. QA statement)

Remarks:

Swiss federal office of public health, Bern, Switzerland

Type of method:

column elution method

Water solubility:

1.84 mg/L

Temp.:

20 °C

pH:

6.72 - 6.91

Remarks on result:

other: Test item Lanthanum carbonate (containing water)

Water solubility:

1.26 mg/L

Temp.:

20 °C

pH:

6.72 - 6.91

Remarks on result:

other: Dry test item (value given in the report: 1.12 mg/L; this was a calculation error)

Details on results:

The analytical method has been validated in a concentration range from 10 µg/L to 2000 µg/L.
The mean recoveries (triplicate measurements) of the spiked concentrations of 10 µg/L, 100 µg/L and 2000 µg/L were found to be 102.2%, 100.1% and 96.0 %, respectively.

Results of the water solubility of Lanthanum carbonate:

Experiment No.	Flow rate (mL/h)	Sample No.	Concentra- tion analysed (µg La/L)	Mean (µg La/L)	Water solubility calculated * (µg Test item/L)	Water solubility calculated (mg Test item/L)	Water solubility calculated (mg Test item/L)	pH
1	31	1.1 1.2	780 766	773.0	1860.230	1.83 SD = ± 0.03 Srel = ± 1.57%	1.84 SD = ± 0.04 Srel = ± 2.33%	6.79
		2.1 2.2	768 765	766.5	1844.588			6.85
		3.1 3.2	764 763	763.5	1837.368			6.91
		4.1 4.2	760 760	760.0	1828.945			6.75
		5.1 5.2	740 742	741.0	1783.222			6.87
		6.1 6.2	746 751	748.5	1801.271			6.85
2	16	7.1 7.2	760 776	768.0	1848.198	1.86 SD = ± 0.05 Srel = ± 2.76%		6.72
		8.1 8.2	736 735	735.5	1769.986			6.87
		9.1 9.2	775 772	773.5	1861.433			6.90
		10.1 10.2	785 786	785.5	1890.311			6.82
		11.1 11.2	768 774	771.0	1855.417			6.89
		12.1 12.2	800 798	799.0	1922.799			6.75

SD Standard deviation

* calculated with a content of lanthanum = 41.554%

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Aug - 18 Aug 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

yes

Type of method:

flask method

Water solubility:

0.8 mg/L

Temp.:

10 °C

pH:

7.9 - 8.1

Remarks on result:

other: Replicates of three days, standard deviation: 0.029

Water solubility:

1.24 mg/L

Temp.:

20 °C

pH:

7.7 - 7.9

Remarks on result:

other: Replicates of three days, standard deviation: 0.043

Water solubility:

1.81 mg/L

Temp.:

30 °C

pH:

7 - 7.3

Remarks on result:

other: Replicates of three days, standard deviation: 0.023

Details on results:

Preliminary test:
The water solubility of Dilanthanum tricarbonate was about 2.5 mg/L at 20.0 °C.

Main test:
The difference between the concentrations of the test substance of day 1 to 3 at 10 °C, 20 °C and 30 °C was <15 % and the concentrations of the test substance showed no relevant tendency. Therefore the mean of day 1 - 3 was taken as the solubility of the test substance at all temperatures, according to the guidelines.
As the temperature coefficient of the solubility of the test substance was >3 % (i.e. 3.8 to 4.6 % ) per °C, the solubility was determined at three temperatures, in agreement with the guideline.

Mass concentration of lanthanum determined at different times of stirring, two solutions used:

Nominal temperature	Equilibrium time	pH of the solutions		Concentration in La (mg/L)		mean	Deviation from the max. concentration (%)
		1st	2nd	1st	2nd
10 °C	1 day	7.9	8.0	0.45	0.45	0.45	- 10
	2 day	8.1	8.0	0.50	0.50	0.50	0
	3 day	8.1	8.1	0.50	0.50	0.50	0
					Mean±SD:	0.48±0.029
20 °C	1 day	7.7	7.8	0.71	0.70	0.71	-9.6
	2 day	7.9	7.9	0.78	0.78	0.78	0
	3 day	7.8	7.9	0.78	0.78	0.78	0
					Mean±SD:	0.76±0.043
30°C	1 day	7.1	7.2	1.07	1.07	1.07	-3.8
	2 day	7.0	7.2	1.11	1.11	1.11	0
	3 day	7.1	7.3	1.10	1.11	1.11	-0.6
					Mean±SD :	1.10±0.023

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

other information

Study period:

23 Mar - 16 Nov 2009

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study, but unsuitable analytical method

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

yes

Remarks:

As preliminary study only one flask was prepared: with 10 mg test substance, mixed with 1000 mL deionised water, skahen for 72 h

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

As preliminary study only one flask was prepared: with 10 mg test substance, mixed with 1000 mL deionised water, skahen for 72 h

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Type of method:

column elution method

Water solubility:

1.45 µg/L

Temp.:

20 °C

pH:

6.5

Details on results:

Water solubility of test item was stated as 1.45 ± 0.28 µg/L.
Standard deviation correlated to a relative standard deviation of 19.3 %.
Variation within the respective flow rates was unobtrusive, but all values showed large variations. The authors stated that this is considered to be due to, firstly, the variation of the analytical method (± 0.2 µg/L), secondly, variation within the samples, and thirdly, measurement uncertainties when determining the volume of the samples resp. adding buffer/Alizarin S.
Following Horwitz (equation: variation = 2^(1 - 0,5 * log c)), a relative standard deviation of 28.7% can be expected when analysing samples with concentrations of 1.45 µg/L. Therefore, the observed standard deviation of 19.3% is considered as uncritical.

Flow rate 1:

sample	Interval (min)	Volume (mL)	Flow rate (ml/h)
1-1	31	12.3	23.8
1-2	27	11.6	25.8
1-3	34	13.3	23.5
1-4	30	12.5	25.0
1-5	28	11.8	25.3
1-6	33	13.5	24.5
1-7	32	12.6	23.6
mean ± standard deviation			24.50 ± 0.921

Flow rate 2:

sample	Interval (min)	Volume (mL)	Flow rate (ml/h)
2-1	57	11.9	12.5
2-2	46	9.4	12.3
2-3	40	8.2	12.3
2-4	45	9.3	12.4
2-5	45	9.4	12.5
2-6	45	8.1	10.8
2-7	64	13.2	12.4
mean ±standard deviation			12.11 ± 0.649

Measurement of La concentration at flow rate 24.6 mL/h

sample	Measured La concentration (µg/L)	Calculated Dilanthanum tricarbonate concentration (µg/L]	Difference to previous sample (%)
1-1	0.65	1.07	-
1-2	0.75	1.24	15.48
1-3	0.83	1.37	10.71
1-4	0.88	1.46	6.26
1-5	0.94	1.55	6.29
1-6	0.98	1.62	4.44
1-7	1.11	1.84	13.67
mean	0.88	1.45

Measurement of La concentration at flow rate 12.11 mL/h

sample	Measured La concentration (µg/L)	Calculated Dilanthanum tricarbonate concentration (µg/L]	Difference to previous sample (%)
2-1	0.71	1.17	-
2-2	0.65	1.07	-9.31
2-3	1.02	1.68	19.42
2-4	0.99	1.63	14.55
2-5	1.13	1.87	9.73
2-6	0.98	1.61	-17.83
2-7	0.67	1.10	-15.39
mean	0.88	1.45

Description of key information

0.80 mg/L at 10°C, 1.24 mg/L at 20 °C, 1.81 mg/L at 30 °C

Key value for chemical safety assessment

Water solubility:

1.24 mg/L

at the temperature of:

20 °C

Additional information

The water solubility of Lanthanum carbonate was investigated with the flask method at three different temperatures according to OECD 105 under GLP conditions (Wenighofer 2010). Due to the water solubility of the test substance determined in the preliminary test, the column elution method should be used for the main test, but this method is not applicable for inorganic substances. In agreement with the guideline, the flask method using a slow stirring technique (< 100 rpm) was chosen. The pH of the solutions were 7.9 to 8.1 at 10 °C, 7.7 to 7.9 °C at 20 °C and 7.0 to 7.3 at 30 °C. The difference between the concentrations of the test substance of day 1 to 3 at 10 °C, 20 °C and 30 °C was < 15% and the concentrations of the test substance showed no relevant tendency. Therefore, the mean of day 1-3 was taken as the solubility of the test substance at all temperatures and the following values were stated: 0.80 mg/L (0.48 mg La/L) with a standard deviation of 0.029 at 10.0 °C, 1.24 mg/L (0.76 mg La/L) with a standard deviation of 0.043 at 20.0 °C and 1.81 mg/L (1.10 mg La/L) with a standard deviation of 0.023 at 30.0 °C.

A further study examined the water solubility with the column elution method also according OECD 105 under GLP-conditions (Weissenfeld 2006). The resulting value for the water solubility was stated as 1.26 mg/L at 20 °C, this is comparable to the value given in the study above.