lipophobic

Lipophobic describes substances that exhibit little or no affinity for lipids. In chemistry, lipophobic compounds have low solubility in lipid or nonpolar environments and tend to be more soluble in polar solvents such as water. The term is often used in contrast with lipophilic, which denotes fat-loving or lipid-soluble substances. Lipophobicity is commonly associated with polarity, ionic charge, or strong hydrogen-bonding capability, which discourages dissolution in nonpolar lipid phases.

The behavior of lipophobic substances can be characterized by partitioning measurements, such as the octanol-water partition coefficient (log P). Lipophobic compounds typically have low log P values, indicating a preference for aqueous over lipid phases. However, interactions with oils or synthetic nonpolar solvents can vary with molecular structure, so lipophobicity is not an absolute property across all lipid-like environments.

In biology and pharmacology, lipophobic compounds may face challenges crossing lipid membranes, potentially limiting systemic distribution or cellular uptake. Formulation strategies often seek to improve lipid compatibility or use delivery systems that bypass purely lipid-based barriers.

Applications of the concept include the design of lipid-repellent or oil-repellent surfaces, selection of solvents and reaction media for sensitive compounds, and assessment of material compatibility in environments where lipid contamination is a concern. Lipophobic principles also inform discussions of solvent quality, extraction methods, and the behavior of compounds in biological and industrial contexts.

See also: lipophilicity, hydrophilicity, oleophobic, partition coefficient.