Relationship between Polysorbate 80 solubilization descriptors and octanol–water partition coefficients of drugs

Abstract

The molar solubilization capacities ( κ) and the molar micelle–water partition coefficients ( K M N) in Polysorbate 80 of several drugs (including barbiturates, steroids, and benzoic acid derivatives) are related to their log octanol–water partition coefficients (log P). Both κ and K M N values were calculated from solubility versus Polysorbate 80 concentration profiles, which were either experimentally determined or obtained from the literature. There is a linear relationship between log P of the tested compounds and the logarithm of the molar micelle–water partition coefficient (log K M N). On the other hand molar solubilization capacities are nearly independent of log P. It is shown that the ability of Polysorbate 80 to solubilize a drug can be predicted from its log P value.