Chromatographic parameter-1-octanol-water partition coefficient

The empirical physicochemical parameters have a good informative value for determining the mechanism of retention operating in a given chromatographic sy.stem. There are exhaustive compilations of such parameters like >/-octanol-water partition coefficients [45,46] or the LSER-based analyte parameters [47,48]. The problem is. however, that there is a lack of such descriptors for many analytes of interest in actual QSRR studies. 

The first exploitation of this relationship in a biological context was by Boyce and Milbarrow [28], who showed a relationship between the molluscicidal activity of some A -alkyltritylamines and their Rm values on TLC plates. Many publications have reported the application of TLC to determine the relative lipophilicity of compounds. The first chapter of the book Chromatographic Determination of Molecular Interactions Applications in Biochemistry, Chemistry, and Biology [29[ summarises the theory and presents the major application fields of the TLC method. The advantage of the method for the determination of lipophilicity is that the layers can be easily covered by octanol and by using an aqueous buffer the retention parameter would be directly proportional to the octanol-water partition coefficients. The drawbacks of this method are the limited reproducibility and precision. 

Generally, the transport parameter used is the logarithm of the partition coefficient of the bas (bioactive substance) or some quantity derived from it. The partition coefficient is almost always determined between water and 1-octanol. Parameters obtained by chromatographic methods are being used with increasing frequency however. The term in t2 is introduced to account for the frequently observed parabolic dependence of a data set of bas on the transport parameter. Models other than... 

---