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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR estimation
Justification for type of information:
KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate. KOWWIN™'s methodology is known as an Atom/Fragment Contribution (AFC) method. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values.

To estimate log P, KOWWIN initially separates a molecule into distinct atom/fragments. In general, each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom. Several functional groups are treated as core "atoms"; these include carbonyl (C=O), thiocarbonyl (C=S), nitro (-NO2), nitrate (ONO2), cyano (-C/N), and isothiocyanate (-N=C=S). Connections to each core "atom" are either general or specific; specific connections take precedence over general connections. For example, aromatic carbon, aromatic oxygen and aromatic sulfur atoms have nothing but general connections; i.e., the fragment is the same no matter what is connected to the atom. In contrast, there are 5 aromatic nitrogen fragments: (a) in a five-member ring, (b) in a six-member ring, (c) if the nitrogen is an oxide-type {i.e. pyridine oxide}, (d) if the nitrogen has a fused ring location {i.e. indolizine}, and (e) if the nitrogen has a +5 valence {i.e. N-methyl pyridinium iodide}; since the oxide-type is most specific, it takes precedence over the other four. The aliphatic carbon atom is another example; it does not matter what is connected to -CH3, -CH2-, or -CH< , the fragment is the same; however, an aliphatic carbon with no hydrogens has two possible fragments: (a) if there are four single bonds with 3 or more carbon connections and (b) any other not meeting the first criteria.
Qualifier:
according to guideline
Guideline:
other: KOWWIN v1.67
Deviations:
not applicable
Principles of method if other than guideline:
KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate. KOWWIN™'s methodology is known as an Atom/Fragment Contribution (AFC) method. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values.

To estimate log P, KOWWIN initially separates a molecule into distinct atom/fragments. In general, each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom. Several functional groups are treated as core "atoms"; these include carbonyl (C=O), thiocarbonyl (C=S), nitro (-NO2), nitrate (ONO2), cyano (-C/N), and isothiocyanate (-N=C=S). Connections to each core "atom" are either general or specific; specific connections take precedence over general connections. For example, aromatic carbon, aromatic oxygen and aromatic sulfur atoms have nothing but general connections; i.e., the fragment is the same no matter what is connected to the atom. In contrast, there are 5 aromatic nitrogen fragments: (a) in a five-member ring, (b) in a six-member ring, (c) if the nitrogen is an oxide-type {i.e. pyridine oxide}, (d) if the nitrogen has a fused ring location {i.e. indolizine}, and (e) if the nitrogen has a +5 valence {i.e. N-methyl pyridinium iodide}; since the oxide-type is most specific, it takes precedence over the other four. The aliphatic carbon atom is another example; it does not matter what is connected to -CH3, -CH2-, or -CH< , the fragment is the same; however, an aliphatic carbon with no hydrogens has two possible fragments: (a) if there are four single bonds with 3 or more carbon connections and (b) any other not meeting the first criteria.
GLP compliance:
no
Type of method:
other: QSAR estmation
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
-3.67
Remarks on result:
other: calculated value

SMILES : NCCNCCNCCNCCNCCN

CHEM  : Polyethylenepolyamine

MOL FOR: C10 H28 N6

MOL WT : 232.38

-------+-----+--------------------------------------------+---------+--------

 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE

-------+-----+--------------------------------------------+---------+--------

 Frag | 10 | -CH2-  [aliphatic carbon]               | 0.4911 | 4.9110

 Frag | 2 | -NH2   [aliphatic attach]               |-1.4148 | -2.8296

 Frag | 4 | -NH-   [aliphatic attach]               |-1.4962 | -5.9848

 Const |    | Equation Constant                        |        | 0.2290

-------+-----+--------------------------------------------+---------+--------

                                                        Log Kow  = -3.6744

 

Conclusions:
The calculated log Kow of the test substance is -3.67.
Executive summary:

The calculated log Kow (-3.67) is less than the bioconcentration threshold (log Kow = 3) indicating that the test substance is not expected to be susceptible to bioaccumulation.  

Description of key information

The calculated log Kow of the test substance is -3.67. Therefore, the test substance is not expected to be susceptible to bioaccumulation.   

Key value for chemical safety assessment

Log Kow (Log Pow):
-3.67
at the temperature of:
20 °C

Additional information