LogP

Overview

This module calculates the value of the octanol-water partition coefficient – LogP. Reliability of predictions is quantitatively estimated via the calculation of the Reliability Index value.

Features

• ...

Interface

ACD/LogP Classic

File:acdlogp classic.png

1. Species: rat, mouse.
   Administration type: intraperitoneal, oral, intravenous, subcutaneous.
2. Predicted LD50 in mg/kg
3. Reliability index (RI):
   RI < 0.3 – Not Reliable,
   RI in range 0.3-0.5 – Borderline Reliability,
   RI in range 0.5-0.75 – Moderate Reliability,
   RI >= 0.75 – High Reliability
4. Up to 5 most similar structures in the training set. The records include structure name, experimental value and similarity index. This index is based on QSAR analysis of logLD50 data. Similarity index varies from zero to unity. Only compounds with similarity index greater than 0.5 are presented.
5. Click the tab to browse for similar structures from various administration types. If no similar structures are found, the tab is disabled.
   

1. Lipophilic parts of the molecule are highlighted in green, hydrophilic groups in red, and the intensity of the color indicates the predicted degree of lipophilicity or hydrophilicity of an atom or a substructure
2. LogP predictions obtained using Two different LogP calculation algorithms (AB/LogP 2.0 and ACD/Labs) are provided. AB/Log 2.0 predictions are supplemented by the assessment of prediction reliability by the means of calculated Reliability Index value
3. Up to 5 most similar drug-like structures with experimental parameters

Note: Prediction reliability classification according to Reliability Index (RI) values:

• RI < 0.3 – Not Reliable,
• RI in range 0.3-0.5 – Bordeline Reliability,
• RI in range 0.5-0.75 – Moderate Reliability,
• RI >= 0.75 – High Reliability

ACD/LogP GALAS

File:acdlogp galas.png

1. Species: rat, mouse.
   Administration type: intraperitoneal, oral, intravenous, subcutaneous.
2. Predicted LD50 in mg/kg
3. Reliability index (RI):
   RI < 0.3 – Not Reliable,
   RI in range 0.3-0.5 – Borderline Reliability,
   RI in range 0.5-0.75 – Moderate Reliability,
   RI >= 0.75 – High Reliability
4. Up to 5 most similar structures in the training set. The records include structure name, experimental value and similarity index. This index is based on QSAR analysis of logLD50 data. Similarity index varies from zero to unity. Only compounds with similarity index greater than 0.5 are presented.
5. Click the tab to browse for similar structures from various administration types. If no similar structures are found, the tab is disabled.
   

1. Lipophilic parts of the molecule are highlighted in green, hydrophilic groups in red, and the intensity of the color indicates the predicted degree of lipophilicity or hydrophilicity of an atom or a substructure
2. LogP predictions obtained using Two different LogP calculation algorithms (AB/LogP 2.0 and ACD/Labs) are provided. AB/Log 2.0 predictions are supplemented by the assessment of prediction reliability by the means of calculated Reliability Index value
3. Up to 5 most similar drug-like structures with experimental parameters

Note: Prediction reliability classification according to Reliability Index (RI) values:

• RI < 0.3 – Not Reliable,
• RI in range 0.3-0.5 – Bordeline Reliability,
• RI in range 0.5-0.75 – Moderate Reliability,
• RI >= 0.75 – High Reliability

Consensus LogP

File:logp consensus.png

1. Species: rat, mouse.
   Administration type: intraperitoneal, oral, intravenous, subcutaneous.
2. Predicted LD50 in mg/kg
3. Reliability index (RI):
   RI < 0.3 – Not Reliable,
   RI in range 0.3-0.5 – Borderline Reliability,
   RI in range 0.5-0.75 – Moderate Reliability,
   RI >= 0.75 – High Reliability
4. Up to 5 most similar structures in the training set. The records include structure name, experimental value and similarity index. This index is based on QSAR analysis of logLD50 data. Similarity index varies from zero to unity. Only compounds with similarity index greater than 0.5 are presented.
5. Click the tab to browse for similar structures from various administration types. If no similar structures are found, the tab is disabled.
   

1. Lipophilic parts of the molecule are highlighted in green, hydrophilic groups in red, and the intensity of the color indicates the predicted degree of lipophilicity or hydrophilicity of an atom or a substructure
2. LogP predictions obtained using Two different LogP calculation algorithms (AB/LogP 2.0 and ACD/Labs) are provided. AB/Log 2.0 predictions are supplemented by the assessment of prediction reliability by the means of calculated Reliability Index value
3. Up to 5 most similar drug-like structures with experimental parameters

Note: Prediction reliability classification according to Reliability Index (RI) values:

• RI < 0.3 – Not Reliable,
• RI in range 0.3-0.5 – Bordeline Reliability,
• RI in range 0.5-0.75 – Moderate Reliability,
• RI >= 0.75 – High Reliability

Technical information

LogP module provides the estimate of the value of the octanol-water partitioning coefficient for neutral species. Reliability of each prediction is quantitatively estimated via the calculation of the Reliability Index value. In addition a color-coded representation of the predicted property distribution is provided indicating lipophilic and hydrophilic parts of the compound structure.

Training set size: 11,387
Internal validation set size: 4,890
Main sources of experimental data:

• Reference books:
  • The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals, O'Neil, M.J., Smith, A., Heckelman, P.E., Budavari, S., Eds. 13th Edition, Merck & Co., Inc., Whitehouse Station, NJ, 2001
  • Therapeutic Drugs, Dolery, C., Ed. 2nd Edition, Churchill Livingstone, New York, NY, 1999
  • Clarke's Isolation and Identification of Drugs, Moffat, A.C., Jackson, J.V., Moss, M.S., Widdop, B., Eds. 2nd Edition, The Pharmaceutical Press, London, 1986
• Various articles from peer-reviewed scientific journals*
• Other public data sources (online databases, handbooks, etc.)

* - Articles reporting LogP models by other authors were the predominant type among analyzed literature, meaning that each publication contained larger collections of experimental data (usually in the order of tens or hundreds compounds) compiled from corresponding original experimental articles.

Internal Validation

Table 1. ACD/LogP (AB/LogP v2.0) model performance statistics for the various fractions of the internal validation set.

Subset	Coverage of the entire internal validation set (N=4,890)	R2	RMSE
RI > 0.3 N = 4,872	99.6%	0.94	0.46
RI > 0.5 N = 4,772	97.6%	0.95	0.44
RI > 0.75 N = 3,345	68.7%	0.96	0.36