liposoluble

Liposoluble describes a substance’s tendency to dissolve in fats or lipids rather than in water. It is closely related to lipophilicity, the affinity for nonpolar solvents. Liposoluble compounds typically exhibit a high partition coefficient (logP) and show much greater solubility in organic solvents such as hexane than in water.

Fat-soluble vitamins A, D, E and K are classic examples of liposoluble substances; they require dietary fats for efficient intestinal absorption and are stored in the liver and adipose tissue. Because they can accumulate with excess intake, liposoluble vitamins carry a higher risk of toxicity compared to water-soluble vitamins. Many liposoluble drugs are also highly lipophilic, allowing them to diffuse across cell membranes and distribute widely into fatty tissues, sometimes persisting longer in the body.

Measurement and implications: liposolubility is commonly quantified by partitioning behavior between aqueous and lipid phases, such as the octanol–water partition coefficient (logP). In practice, liposoluble compounds tend to be poorly water-soluble but soluble in fats and nonpolar solvents, influencing formulation, dosing, and elimination. The term is often used interchangeably with lipophilic, though lipophilicity more broadly describes affinity for lipids rather than solubility alone.