Computer programs CLOGP

In the following, the atom/fragment contribution method (AFC method) developed by Meylan and Howard (1995) is used to illustrate the approach. This method is similar to the CLOGP method, but it is easier to see its application without using a computer program. Here, we confine ourselves to a few selected examples of fragment coefficients and correction factors. This will reveal how the method is... 

A computer calculation often can detect errors in published values that may not be immediately apparent to the average researcher. For instance, a measured log P(oct) value for toluene diamine was reported as 3.16 (Veith, 1979) but three computer programs show it to be three log units lower ACD = -0.36 KOWWIN = 0.16 CLOGP = 0.14. One then wonders if a typographical error occurred, and the measured value was 0.16, not 3.16. 

Volume 2 of "Exploring QSAR" by Hansch and Leo (1995) contains the most extensive hard-copy database of log Poct values — about 18,000 values for over 16,500 structures. Sangster (1989) has published log P measurements and offers a comparable computer database on diskettes. Several of the computerized calculation programs access a similar log Poct database. If values in other solvent/ water systems are needed, the MASTERFILE database can accompany the CLOGP program on VAX and UNIX systems and contains about 40,000 measured log P values in over 300 solvent systems in addition to about 10,000 measured values of pKa. 

The methodology of the CLOGP program is somewhat unique in that fragments are determined by the computer—not preset by the designer. As will become evident, this has advantages in how much valuable latent information ... 

This is the program UDRIVE which provides access to CLOGP and CMR calculation algorithms, as well as the database routine THOR running on DEC VAX computers. See Software appendix for more details. 

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