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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
This endpoint study record is part of a Weight of Evidence approach. QSAR may be used in estimating the LogKow of the organic part, the acetate and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR INFORMATIONS : Quantitative Structure Activity Relationships (QSAR) are theoretical models that can be used to predict in a qualitative or quantitative manner the physico-chemical, toxicological, ecotoxicological and environmental fate properties of compounds from a knowledge of their chemical structure.

1. SOFTWARE : EPI Suite

2. MODEL (incl. version number) : EPIWEB 4.11 Kowwin Version 1.68 (september 2010)

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : SMILES of the substance :[Sr](OC(=O)C)OC(=O)C
Name : Strontium diacetate
CAS : 543-94-2

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "When no experimental data of high quality are available, or if experimental methods are known to be unreliable, valid (Q)SARs for log Kow may be used e.g. in a weight-of-evidence approach."
No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.
- Defined endpoint: Partition coefficient
- Methodology : 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 coeffici ent 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.
KOWWIN’s "reductionist" fragment constant methodology (i.e. derivation via multiple regression) differs from the "constructionist" fragment constant methodology of Hansch and Leo (1979) that is available in the CLOGP Program (Daylight, 1995). See the Meylan and Howard (1995) journal article for a more complete description of KOWWIN’s methodology.
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.

5. APPLICABILITY DOMAIN
No formal QMRF assessment of the model is currently available, however, the user's guide describes all the information.

- Descriptor domain: organic chemical
QSAR may be used in estimating the LogKow of the organic part (but not applicable to the ion pair).

- Structural and mechanistic domains:
Training Set Molecular Weights: Minimum MW: 18.02 Maximum MW: 719.92 Average MW: 199.98 Appendix D of the KOWWIN Help gives the maximum number of fragments that occur in any individual compound of the training set.
- Similarity with analogues in the training set: The KOWWIN training and validation datasets can be downloaded from the Internet at http://esc.syrres.com/interkow/KowwinData.htm
Qualifier:
according to guideline
Guideline:
other: Epi Suite v1.68
Version / remarks:
KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method.  
see Meylan, W.M. and P.H. Howard. 1995.  Atom/fragment contribution method for estimating octanol-water partition coefficients.  J. Pharm. Sci. 84: 83-92.
GLP compliance:
not specified
Type of method:
other: QSAR model
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
The substance is a mono-constituent substance; the prediction is done on the constituent.
Type:
log Pow
Partition coefficient:
-0.58
Remarks on result:
other: QSAR (KOWWIN) with strontium acetate. Sr2+ ion cannot be represented in the model.
Remarks:
Temperature and pH value are not specified by the QSAR model.
Conclusions:
The partition coefficient (log Pow) of the test item (strontium di(acetate)) was estimated to be -0.58 with (Q)SAR model EPI Suite software tool.
Executive summary:

The partition coefficient was estimated using the (Q)SAR model EPI Suite v1.68. This is a valid model for this substance which falls into its applicability domain.

The partition coefficient of strontium di(acetate) was estimated to be -0.58.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1.HYPOTHESIS FOR THE ANALOGUE APPROACH
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids under pH conditions can be seen as carboxilic cid, metal salt).

2. SOURCE AND TARGET CHEMICAL(S)
Analogue approach between acetic acid, strontium salt and acetic acid.

3. ANALOGUE APPROACH JUSTIFICATION
Thus, this endpoint study record is part of a Weight of Evidence approach comprising a read-across and a QSAR. QSAR may be used in estimating the LogKow of the organic part, the acetate and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR INFORMATIONS : Quantitative Structure Activity Relationships (QSAR) are theoretical models that can be used to predict in a qualitative or quantitative manner the physico-chemical, toxicological, ecotoxicological and environmental fate properties of compounds from a knowledge of their chemical structure.

a. SOFTWARE : EPI Suite

b. MODEL (incl. version number) : EPIWEB 4.1 Version 1.68

c. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : SMILES of the Read across substance (acetic acid).

d. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "When no experimental data of high quality are available, or if experimental methods are known to be unreliable, valid (Q)SARs for log Kow may be used e.g. in a weight-of-evidence approach."

e. APPLICABILITY DOMAIN
QSAR may be used in estimating the LogKow of the organic part.

f. ADEQUACY OF THE RESULT
This endpoint study record is part of a Weight of Evidence approach comprising a a QSAR (this study) and a read-across. Both data sources agree in the estimated value of log Kow and are sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
The read-across can be performed because of common functional group(s) (i.e. QSAR may be used in estimating the LogKow of the organic part).
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
other: EPI Suite v1.68
Version / remarks:
KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method.  
see Meylan, W.M. and P.H. Howard. 1995.  Atom/fragment contribution method for estimating octanol-water partition coefficients.  J. Pharm. Sci. 84: 83-92.
GLP compliance:
not specified
Type of method:
other: QSAR model
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
The substance is a mono-constituent substance; the prediction is done on the constituent.
Type:
log Pow
Partition coefficient:
0.09
Remarks on result:
other: QSAR (KOWWIN) with acetic acid.
Remarks:
Temperature and pH value are not specified by the QSAR model.
Conclusions:
The partition coefficient (log Pow) of the test item (acetic acid) was estimated to be 0.09 with (Q)SAR model EPI Suite software tool.
Executive summary:

The partition coefficient was estimated using the (Q)SAR model EPI Suite v1.68. This is a valid model for this substance which falls into its applicability domain.

The partition coefficient of acetic acid was estimated to be 0.09.

It is reasonable to think that the partition coefficient of strontium di(acetate) will be of this order of magnitude.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1.HYPOTHESIS FOR THE ANALOGUE APPROACH
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids).

2. SOURCE AND TARGET CHEMICAL(S)
Analogue approach between Strontium di(acetate) and Calcium di(acetate).

3. ANALOGUE APPROACH JUSTIFICATION
Thus, this endpoint study record is part of a Weight of Evidence approach comprising a read-across and a QSAR. QSAR may be used in estimating the LogKow of the organic part, the acetate and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR INFORMATIONS : Quantitative Structure Activity Relationships (QSAR) are theoretical models that can be used to predict in a qualitative or quantitative manner the physico-chemical, toxicological, ecotoxicological and environmental fate properties of compounds from a knowledge of their chemical structure.

a. SOFTWARE : EPI Suite

b. MODEL (incl. version number) : EPIWEB 4.1 Version 1.68

c. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : SMILES of the Read across substance (Calcium diacetate).

d. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "When no experimental data of high quality are available, or if experimental methods are known to be unreliable, valid (Q)SARs for log Kow may be used e.g. in a weight-of-evidence approach."

e. APPLICABILITY DOMAIN
QSAR may be used in estimating the LogKow of the organic part (but not applicable to the ion pair).

f. ADEQUACY OF THE RESULT
This endpoint study record is part of a Weight of Evidence approach comprising a a QSAR (this study) and a read-across. Both data sources agree in the estimated value of log Kow and are sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
The read-across can be performed because of common functional group(s) (i.e. QSAR may be used in estimating the LogKow of the organic part).
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
other: EPI Suite V1.68
Version / remarks:
KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method.  
see Meylan, W.M. and P.H. Howard. 1995.  Atom/fragment contribution method for estimating octanol-water partition coefficients.  J. Pharm. Sci. 84: 83-92.
GLP compliance:
not specified
Type of method:
other: QSAR model
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
The substance is a mono-constituent substance; the prediction is done on the constituent.
Type:
log Pow
Partition coefficient:
-1.377
Remarks on result:
other: QSAR (KOWWIN) with calcium acetate. Ca2+ ion cannot be represented in the model.
Remarks:
Temperature and pH value are not specified by the QSAR model.
Details on results:
QSAR was used to estimate the log Kow of the organic part of the substance (acetate) as the determination of partition coefficient octanol/water is not needed for the inorganic part of the substance (Ca2+).
Conclusions:
The partition coefficient (log Pow) of the test item (calcium di(acetate)) was estimated to be -1.3774 with (Q)SAR model EPI Suite software tool.

Executive summary:

The partition coefficient was estimated using the (Q)SAR model EPI Suite v1.68. This is a valid model for this substance which falls into its applicability domain.

The partition coefficient of calcium di(acetate) was estimated to be -1.3774.

It is reasonable to think that the partition coefficient of strontium di(acetate) will be of this order of magnitude.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1.HYPOTHESIS FOR THE ANALOGUE APPROACH
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids).

2. SOURCE AND TARGET CHEMICAL(S)
Analogue approach between Strontium di(acetate) and Sodium acetate.

3. ANALOGUE APPROACH JUSTIFICATION
Thus, this endpoint study record is part of a Weight of Evidence approach comprising a read-across and a QSAR. QSAR may be used in estimating the LogKow of the organic part, the acetate and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR INFORMATIONS : Quantitative Structure Activity Relationships (QSAR) are theoretical models that can be used to predict in a qualitative or quantitative manner the physico-chemical, toxicological, ecotoxicological and environmental fate properties of compounds from a knowledge of their chemical structure.

a. SOFTWARE : EPI Suite

b. MODEL (incl. version number) : EPIWEB 4.1 Version 1.68

c. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : SMILES of the Read across substance (Sodium acetate).

d. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "When no experimental data of high quality are available, or if experimental methods are known to be unreliable, valid (Q)SARs for log Kow may be used e.g. in a weight-of-evidence approach."

e. APPLICABILITY DOMAIN
QSAR may be used in estimating the LogKow of the organic part (but not applicable to the ion pair).

f. ADEQUACY OF THE RESULT
This endpoint study record is part of a Weight of Evidence approach comprising a a QSAR (this study) and a read-across. Both data sources agree in the estimated value of log Kow and are sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
The read-across can be performed because of common functional group(s) (i.e. QSAR may be used in estimating the LogKow of the organic part).
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
other: Epi Suite v1.68
Version / remarks:
KOWWIN’s methodology is known as an Atom/Fragment Contribution (AFC) method.  
see Meylan, W.M. and P.H. Howard. 1995.  Atom/fragment contribution method for estimating octanol-water partition coefficients.  J. Pharm. Sci. 84: 83-92.
GLP compliance:
not specified
Type of method:
other: QSAR model
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
The substance is a mono-constituent substance; the prediction is done on the constituent.
Type:
log Pow
Partition coefficient:
-3.72
Remarks on result:
other: QSAR (KOWWIN) with sodium acetate. Na+ cannot be represented in the model.
Remarks:
Temperature and pH value are not specified by the QSAR model.
Details on results:
QSAR was used to estimate the log Kow of the organic part of the substance (acetate) as the determination of partition coefficient octanol/water is not needed for the inorganic part of the substance (Na+).
Conclusions:
The partition coefficient (log Pow) of the test item (sodium acetate) was estimated to be -3.72 with (Q)SAR model EPI Suite software tool.
Executive summary:

The partition coefficient was estimated using the (Q)SAR model EPI Suite v1.68. This is a valid model for this substance which falls into its applicability domain.

The partition coefficient of sodium acetate was estimated to be -3.72.

It is reasonable to think that the partition coefficient of strontium di(acetate) will be of this order of magnitude.

Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1.HYPOTHESIS FOR THE ANALOGUE APPROACH
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids).

2. SOURCE AND TARGET CHEMICAL(S)
Analogue approach between Strontium di(acetate) and other di(acetate) salts and/or acetic acid.

3. ANALOGUE APPROACH JUSTIFICATION
Thus, this endpoint study record is part of a Weight of Evidence approach comprising a read-across and a QSAR. QSAR may be used in estimating the LogKow of the organic part, the acetate and allows to fulfil the information requirements as further explained in the provided endpoint summary.

QSAR INFORMATIONS : Quantitative Structure Activity Relationships (QSAR) are theoretical models that can be used to predict in a qualitative or quantitative manner the physico-chemical, toxicological, ecotoxicological and environmental fate properties of compounds from a knowledge of their chemical structure.

a. SOFTWARE : EPI Suite

b. MODEL (incl. version number) : EPIWEB 4.1 Version 1.68

c. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL : SMILES of the Read across substance.

d. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
According to the guidance R.7a - version 5 - December 2016, "When no experimental data of high quality are available, or if experimental methods are known to be unreliable, valid (Q)SARs for log Kow may be used e.g. in a weight-of-evidence approach."

e. APPLICABILITY DOMAIN
QSAR may be used in estimating the LogKow of the organic part (but not applicable to the ion pair).

f. ADEQUACY OF THE RESULT
This endpoint study record is part of a Weight of Evidence approach comprising a a QSAR (this study) and a read-across. Both data sources agree in the estimated value of log Kow and are sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
The read-across can be performed because of common functional group(s) (i.e. QSAR may be used in estimating the LogKow of the organic part).
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across: supporting information
Type:
log Pow
Partition coefficient:
-1.377
Remarks on result:
other: QSAR (KOWWIN) with calcium acetate. Ca2+ ion cannot be represented in the model.
Remarks:
Temperature and pH value are not available in the QSAR model.
Type:
log Pow
Partition coefficient:
-3.72
Remarks on result:
other: QSAR (KOWWIN) with sodium acetate. Na+ cannot be represented in the model.
Remarks:
Temperature and pH value are not available in the QSAR model.
Type:
log Pow
Partition coefficient:
0.09
Remarks on result:
other: QSAR (KOWWIN) with acetic acid. Temperature and pH value are not available in the QSAR model.
Conclusions:
An analogue approach between Strontium di(acetate) and other acetate metal salts has been also conducted.
The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids).
Indeed, the partition coefficient of the other metal acid acetate salts are of this order of magnitude, also estimated by QSAR model EPI Suite v1.68.

Description of key information

The partition coefficient of the test item (strontium di(acetate)) was estimated using the (Q)SAR model EPI Suite v1.68. This is a valid model for this substance which falls into its applicability domain.

The partition coefficient of strontium di(acetate) was estimated to be -0.58.

An analogue approach between Strontium di(acetate) and other acetate metal salts has been also conducted.

The hypothesis is that properties are likely to be similar or follow a similar pattern as a result of the presence of a common organic part. This is a reasonable assumption for the majority of organic salt compounds (e.g. metal salts of some organic acids).

Indeed, the partition coefficient of the other metal acid acetate salts are of this order of magnitude, also estimated by QSAR model EPI Suite v1.68.

Key value for chemical safety assessment

Log Kow (Log Pow):
-0.58
at the temperature of:
20 °C

Additional information