lipofili

Lipofili, also known as lipophilicity or lipophily, is a chemical property that describes the affinity of a compound for lipids and nonpolar environments relative to water. It characterizes how readily a substance partitions into oily or fatty phases versus aqueous ones, and it is a key factor in predicting behavior in biological systems and the environment.

Lipophilicity is commonly expressed by the partition coefficient between octanol and water, or P, often summarized as logP for the neutral form of a molecule. For ionizable compounds, logD is used to reflect lipophilicity at a specific pH. Values vary widely: more positive logP/logD indicate greater lipophilicity, while negative values indicate hydrophilicity. Measurements can be experimental (shake-flask methods, chromatography) or computed from molecular structure.

Several factors influence lipofili: molecular size and shape, the number and arrangement of hydrophobic moieties (alkyl and aryl groups), polar surface area, hydrogen-bond donors and acceptors, and the ionization state determined by pH (pKa). Ionized species are typically less lipophilic than their neutral counterparts.

Implications for biology and medicine are significant. Lipophilicity affects membrane permeability and oral absorption, as well as distribution into tissues and crossing of barriers such as the blood–brain barrier. It also influences solubility in water, plasma protein binding, metabolism, and excretion. In environmental science, higher lipophilicity often correlates with greater bioaccumulation and persistence, guiding risk assessments and regulatory decisions.

In drug design and toxicology, lipofili is balanced with solubility and specificity to optimize pharmacokinetic properties and safety.