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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Not stated
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
according to
Guideline:
other: OECD proposal, Document PC 84.1, draft May 1984, adapted by Duphar (Journal of Chromatography, 320: 271-279 and 352: 455-463
Deviations:
not specified
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
yes
Remarks:
Measurements were performed at a higher wavelength than recomended by the guideline.
GLP compliance:
no
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
2.7
Temp.:
22 °C
pH:
3
Details on results:
tr: 7.1/7.1
k' 4.83
log P 2.70

Table 2: Reference substance results

 Substance  Retention times (tr) - duplicate determinations  Capacity ratios (k')  Log capacity ratios (log k')
 Morphine  1.9/1.9  0.57  -0.24
 Atropine  3.9/3.9  2.25  0.35
 Nitrobenzene  3.8/3.9  2.20  0.34
 Benzophenone  9.5/9.5  6.90  0.84
 Naphthalene  11.8/11.7  8.80  0.94
 Diphenylamine  11.8/11.8  8.82  0.95
 Biphenyl  19.0/19.0  14.82  1.17
 Halopemide  17.6/17.5  13.65  1.13
 Dichromate (t0)  1.2/1.2    

The relationship between the logarithims of n-octanol/water partition coefficient (log P) and the logarithims of the capacity ratios of the reference substances can be described by the following equation:

log P = 2.54 log k' + 0.97

(n = 8; r = 0.999; s = 0.06; F = 3194)

Conclusions:
Under the conditions of the test, the partition coefficient of the test material was determined to be log Pow 2.70 using the HPLC method.
Executive summary:

In a non-GLP partition coefficient study conducted in accordance with a proposed OECD guideline, the partition coefficient was determined using the HPLC method. Under the conditions of the test, the log Pow of the test material was determined to be 2.70.

Description of key information

The log Pow of the test material was determined to be 2.70 according to a study performed in line with modified OCED method (OCED proposal, Document PC 84.1, draft May 1984, adapted by Duphar (Journal of Chromatography, 320: 271-279 and 352: 455-463).

Key value for chemical safety assessment

Log Kow (Log Pow):
2.7
at the temperature of:
20 °C

Additional information

The key study (Thus, 1985) was performed in line with a modified OECD method, but not to GLP, with a sufficient level of detail to assess the quality of the study. The study was performed to a good standard and was assigned a reliability score of 2 using the principle for assessing data quality as set out in Klimisch (1997) on the basis that the study was not performed to GLP.