Myo-Inositol, hexakis(dihydrogen phosphate), sodium salt

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 15 August 2018 to 05 September 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

OECD Guidelines for the Testing of Chemicals, Method No. 105, adopted 27. Jul. 1995: “Water Solubility “

Deviations:

yes

Remarks:

- Sampling was not performed after 1 – 3 d shaking. - Fivefold excess as proposed in the guidelines could not be used The deviations were assessed by the study director and were stated as uncritical.

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Name: dermofeel PA-3 (dried)
- CAS No.: 14306-25-3
- EC No.: 238-242-6
- Source and lot/batch No.of test material: NA2253
- Appearance: white solid powder
- Production date: June 2016
- Expiration date of the lot/batch: June 2019

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: closed vessel; room temperature (20 +- 5 °C); protected from light and humidity

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- The test item was finely ground

Key result

Water solubility:

>= 1 163.43 - <= 1 216.41 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

2 860 g/L

Incubation duration:

ca. 8 d

Temp.:

20 °C

pH:

2

Measurements during Equilibration

Visual inspection was performed during equilibration time (flask 1A-C, days 2 – 4) only. Measurements were regarded to be not necessary, because flask 1A (time 2 d) showed definitely more residue than flask 1B (time 3 d), and no residue was noticed in flask 1C (time 4 d). Equilibration was not achieved after 2 d shaking. Sampling and measurement of flasks 1A-C was performed on days 5 - 7. The data are presented in the following table:

Table Equilibration Phase

Time [d] (flask)	Temperature [°C]	pH*	Dilution factor	Absorption	Absorption Mean	Mean Concentration Phosphate in the Measuring Solution [mg/L]	Mean Concentration Test Item in the Filtrate [g/L]	Difference to previous sample [%]
5d (1A)	20.3	2	40000	0.4782	0.4766	1.87	1228.19	-
				0.4750
6d (1B)	20.4	2	40000	0.4680	0.4658	1.83	1200.97	-2.2
				0.4636
7d (1C)	20.5	2	40000	0.4588	0.4639	1.82	1196.06	-0.4
				0.4689

* pH was tested using Tritest indicator paper Equilibration was regarded to be achieved after 5 d shaking, because no rising tendency

and no difference >15% of test item concentrations in the filtrates were detected.

Measurements at Plateau

Equilibration was regarded to be achieved after 5 d shaking, but the final measurement was performed after 8 d shaking for organizational reasons.

Table Measurements at Plateau

Time [d] (flask)	Temperature [°C]	pH*	Dilution factor	Absorption	Absorption Mean	Mean Concentration Phosphate in the Measuring Solution [mg/L]	Mean Concentration Test Item in the Filtrate [g/L]
Blank**	-	-	40000	-0.0008	-0.0004	<0.1	-
				0.0000
8 d (2)	20.3	2	40000	0.4576	0.4584	1.80	1182.20
				0.4591
8 d (3)	19.8	2	40000	0.4441	0.4501	1.77	1161.29
				0.4560
8 d (4)	20.2	2	40000	0.4585	0.4620	1.82	1191.27
				0.4654
8 d (5)	20.5	2	40000	0.4744	0.4753	1.87	1224.91
				0.4762

* pH was tested using Tritest indicator paper

**measured after 5 d shaking

Measurements of unbounded Phosphate at Plateau

Samples were measured without digestion exemplarily only at the end of the main test in the filtrates of vessels 2 and 3 to show the determined phosphate is mainly bounded phosphate.

The results are shown in Table "Measurements at Plateau of unbounded Phosphate"

Table Measurements at Plateau of unbounded Phosphate

Time [d] (flask)	Dilution factor	Absorption	Absorption Mean	Mean Concentration Phosphate in the Measuring Solution [mg/L]	Mean Concentration Test Item in the Filtrate  [g/L]
8 d (2)	40000	0.3991	0.3970	1.57	94.64
		0.3949
8 d (3)	40000	0.3553	0.3550	1.40	84.88
		0.3546
Mean ConcentrationTest Item in the Filtrate [g/L]					89.76

89.76 g/L unbounded phosphate (mean of vessels 2 and 3) corresponds to 7.5 % of the phosphate, measured after digestion. Therefore, phosphate determined after digestion during this study is mainly bounded Phosphate.

Results

The measurements of flasks 2-5 were used for the calculation of the mean.

Table Measurements used for Calculation of Solubility

Flask	Concentration Test Item [g/L]	Total Mean [g/L]	Total Standard Deviation [g/L]
2	1182.20	1189.92	26.49 (RSD 2.2%)*
3	1161.29
4	1191.27
5	1224.91

*RSD = relative standard deviation

Mean at the plateau is 1189.92 ± 26.49 g/L at 19.8 –20.5°C (20.0 ± 0.5°C).

Conclusions:

Water solubility of the test item (OECD 105, flask method): 1189.92 ± 26.49 g/L at 20 ± 0.5°C
= 1189.92 ± 26.49 kg/m3 (SI units)
(mean value ± standard deviation of four individual vessels)

Executive summary:

The solubility of the test item in water was determined by measurement of phosphate as ingredient of the test item in the filtrated test solutions using photometer. All replicates showed good correspondence. Standard deviation of the four flasks which were used for the calculation of water solubility at the plateau was

1189.92 ± 26.49 g/L at 20.0 ± 0.5°C (OECD 105, nominal load 2.86 kg/L)

corresponding to a relative standard deviation of 2.2 %. The pH value was 2 in all four flasks, the test temperature was in the acceptable range with 19.8 – 20.5 °C over the test duration (measured in the liquid at sampling time points).

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.

Description of key information

Water solubility of the test item (OECD 105, flask method):  1189.92 ± 26.49 g/L at 20 ± 0.5°C

= 1189.92 ± 26.49 kg/m3 (SI units)

(mean value ± standard deviation of four individual vessels)

Key value for chemical safety assessment

Water solubility:

1 189.92 g/L

at the temperature of:

20 °C

Additional information

The solubility of the test item in water was determined by measurement of phosphate as ingredient of the test item in the filtrated test solutions using photometer. All replicates showed good correspondence. Standard deviation of the four flasks which were used for the calculation of water solubility at the plateau was

1189.92 ± 26.49 g/L at 20.0 ± 0.5°C (OECD 105, nominal load 2.86 kg/L)

corresponding to a relative standard deviation of 2.2 %. The pH value was 2 in all four flasks, the test temperature was in the acceptable range with 19.8 – 20.5 °C over the test duration (measured in the liquid at sampling time points).

No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.