P is the logarithm of the partition coefficient of a compound between octanol and water.
It is a physico-chemical parameter that has a correlation with absorption of small molecules into physiological membranes. P refers to the neutral form of the compound. PrologP 5.1 is the latest version of CompuDrug's log P prediction program. A further developed version of Rekker's fragmental method, the atomic approaches of Broto et al. and Ghose et al. are applied. The predicted results of these methods are combined in order to minimize the error of the estimation.