Lipophilic-hydrophilic balance Partition coefficients

Inversely, the presence of ethanol and other alcohols in hydroalcoholic preparations may cause loss of solubility of hydrophilic peptides. In these products polypeptides with high hydrophobicity are preferred. The coefficient of ripartition 2-butanol/water (as nitrogen-partition coefficient) is used to estimate the lipophilic/hydrophilic balance of proteins for hydrophobic hydrolysates the nitrogen-partition coefficient value is 0.1-0.15 and lower for more hydrophilic derivatives (129). 

An important factor in determining the course of uptake, transport, and distribution of xenobiotics is their polarity. Compounds of low polarity tend to be lipophilic and of low water solubility. Compounds of high polarity tend to be hydrophilic and of low fat solubility. The balance between the lipophilicity and hydrophilicity of any compound is indicated by its octanol-water partition coefficient (K J, a value determined when equilibrium is reached between the two adjoining phases ... 

The hydrophile-lipophile balance is related to the solubility of a surfactant. At high HLB the surfactant is very water soluble while at low HLB the surfactant is very lipid soluble. Because HLB is solubility related, it is in turn related to the partition coefficient (or ratio of the solubility of the surfactant in a lipid phase to its solubility in an aqueous phase). A high HLB value suggests a low oil/water partition coefficient, and conversely a low HLB shows a high partition coefficient. Hence, an optimum surfactant HLB for enhancing biological activity also implies an optimum partition coefficient for activity enhancement. 

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