D-mannose

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7550 (Partition Coefficient, n-octanol / H2O, Shake Flask Method)

Deviations:

no

GLP compliance:

yes

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

-2.71

Temp.:

25 °C

pH:

>= 8.04 - <= 8.73

Details on results:

The feasibility trial at a 1:1 n-octanol/water volume ratio yielded a mean estimated partition coefficient of 0.00187 (log (Pow) = -2.73). Based on these results, it was concluded that n-octanol to water volume ratios of 1:1, 2:1 and 1:2 would be appropriate for use in the definitive test.
The stock solution of D-Mannose in reagent water saturated with n-octanol used to fortify the definitive partition samples had a mean measured concentration of 3.18 mg a.s./mL (n = 3), which corresponded to 106% of the nominal D-Mannose concentration.

Prior to the definitive test, the measured pH of the aqueous partition phase (reagent water saturated with n-octanol) was 8.04. The measured pH value of the aqueous phase from a selected partition sample was 8.73.
The total mass recovered was calculated for each of the six definitive test vessels. Mass balance was obtained for D-Mannose in all vessels. The overall mean percent recovery for D-Mannose for the six partition test vessels was 107 ± 13%. The 1:2 ratio partition samples had higher mass balances than the partition samples from the other two ratios possibly due to a fortification/dilution error, however the Pow results agreed with the other two ratios.
Partition coefficients were calculated from the measured concentrations of D-Mannose in each phase for each of six samples. Overall mean n-octanol/water partition coefficients and overall mean of the logarithm (base 10) of the n-octanol/water partition coefficients were calculated for each of the six samples. The mean Pow values for D-Mannose at n-octanol/water solvent ratios of 1:1, 1:2 and 2:1 were determined to be 0.00214, 0.00168 and 0.00204, respectively. The corresponding mean log (Pow) values were -2.67, -2.78 and -2.69, respectively. The overall mean log (Pow) was -2.71 ± 0.065 (n = 6).

Measured Concentrations and Partition Coefiicient Results of the n-Octanol/Water Partition Coefficient Definitive Test with D-Mannose

Sample ID^1	Solvent Ratio^2	Measured Concentration (M)	Pow	Mean Pow	Log Pow	Mean Log Pow
1-oct	1:1	1.24x10^-5	0.00241	0.00214	-2.62	-2.67
1-aq		5.15x10^-3
2-oct	1:1	1.06x10^-5	0.00187		-2.73
2-aq		5.66x10^-3
3-oct	1:2	7.83x10^-6	0.00158	0.00168	-2.80	-2.78
3-aq		4.95X10^-3
4-oct	1:2	9.21C10^-6	0.00177		-2.75
4-aq		5.21x10^-3
5-oct	2:1	1.61x10-5	0.00191	0.00204	-2.72	-2.69
5-aq		8.44x10^-3
6-oct	2:1	1.78x10-5	0.00217		-2.66
6-aq		8.22x10^-3
Overall Mean:			0.00195		-2.71
Standard Deviation:			0.00030		0.065
% RSD			15		2.4
^1“oct” = n-octanol phase and “aq” = aqueous phase of a given test system. ^2Expressed as the volume ratio of n-octanol to water.

Conclusions:

This study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).
The overall mean n-octanol/water partition coefficient of D-Mannose at 25ºC in reagent water was 0.00195 corresponding to a log (Pow) of -2.71 ± 0.065 (n = 6, %RSD = 2.4%).

Executive summary:

A study was performed to determine the n-octanol/water partition coefficient of the test substance using the HPLC method in accordance with OECD guideline 107. The n-octanol/water partition coefficient of D-Mannose was determined in reagent water (unbuffered at neutral pH) using the flask-shaking method. The method consisted of shaking the solute (D-Mannose) with the two immiscible solvents (n-octanol and reagent water) at 25°C for a minimum of 25 minutes and analyzing the n-octanol and aqueous phases for the solute concentration using HPLC/UV and LC/MS/MS. Partition coefficients were calculated from the measured concentrations of D-Mannose in each phase for each of six samples. Overall meann-octanol/water partition coefficients and overall mean of the logarithm (base 10) of then-octanol/water partition coefficients were calculated for each of the six samples. The mean Pow values for D-Mannose atn-octanol/water solvent ratios of 1:1, 1:2 and 2:1 were determined to be 0.00214, 0.00168 and 0.00204, respectively. The corresponding mean log (Pow) values were -2.67, -2.78 and -2.69, respectively. The overall mean log (Pow) was -2.71 ± 0.065 (n = 6).

Description of key information

OECD Guideline 107

Key value for chemical safety assessment

Log Kow (Log Pow):

-2.71

at the temperature of:

25 °C