lipophiles

Lipophiles, or lipophilic substances, are chemical entities that preferentially associate with lipids or other nonpolar environments rather than with water. They dissolve readily in fats, oils, and nonpolar organic solvents and typically exhibit limited water solubility. Lipophilicity is commonly quantified by partition coefficients such as logP or logD, which describe how a compound distributes between a nonpolar phase (often octanol) and an aqueous phase.

In pharmacology and toxicology, lipophilicity influences a compound’s absorption, distribution, metabolism, and excretion. Lipophilic drugs tend to cross cell membranes by passive diffusion and often distribute widely within the body, including into fatty tissues and the central nervous system. High lipophilicity can improve membrane permeability and oral bioavailability but may reduce aqueous solubility and complicate formulation. Excessively lipophilic molecules may be rapidly metabolized or exhibit greater potential for off-target effects and interactions. Consequently, medicinal chemists aim to balance lipophilicity to achieve sufficient permeability while maintaining solubility and safety.

In environmental science and industry, lipophiles can bioaccumulate in the fatty tissues of organisms and may biomagnify through food webs. They are also central to solvent extraction, chromatography (notably reversed-phase systems), and formulation science, where lipophilicity governs solubility in oils or organic solvents and interactions with nonpolar sorbents.

Terminology commonly uses lipophile as the noun form and lipophilic as the adjective; in practice, lipophiles and lipophilicity are used interchangeably with lipophilic substances and their affinity for lipids.