rasvaliukoinen

Rasvaliukoinen is a Finnish term used in chemistry, pharmacology and nutrition to describe substances that dissolve readily in fats or organic solvents but poorly in water. The word comes from rasva meaning fat and liukoinen meaning soluble. In practice, rasvaliukoinen compounds are typically nonpolar or weakly polar and exhibit high lipophilicity, often reflected by a high octanol–water partition coefficient (log P).

Biological and practical significance is central to the concept. Fat-soluble substances require dietary fat for intestinal absorption, are transported in the bloodstream by lipoproteins, and can accumulate in adipose tissue. They may persist in the body longer than water-soluble substances and can cause toxicity if consumed in excess (for example, hypervitaminosis A or D). In pharmacology, rasvaliukoinen drugs may be formulated in lipid-based delivery systems to improve oral bioavailability and targeting.

Examples commonly cited include fat-soluble vitamins A, D, E and K; many lipophilic pesticides and industrial chemicals such as certain polychlorinated biphenyls (PCBs) and DDT, as well as various lipophilic drugs.

Rasvaliukoinen is often contrasted with vesiliukoinen, meaning water-soluble. Some compounds are amphiphilic and can dissolve in both media under certain conditions, such as changes in polarity, temperature or pH. In environmental science, lipophilic substances tend to bioaccumulate in organisms and can be transported over long distances, influencing ecological risk assessments.