Lipofiele

Lipofiele, also known as lipophilic, describes chemical substances that have an affinity for lipids and nonpolar solvents and limited solubility in water. Lipophilic compounds tend to partition into lipid-rich environments, such as cell membranes and adipose tissue, in contrast to hydrophilic compounds that prefer aqueous phases.

Lipophilicity is commonly quantified by partition coefficients, such as logP, the logarithm of the concentration ratio between octanol and water for the neutral form. For ionizable molecules, logD is used at a given pH. Higher logP or logD values indicate greater lipophilicity but usually lower water solubility.

Biologically, lipophilicity influences absorption, distribution, metabolism, and excretion (ADME). Lipophilic drugs cross membranes readily and can reach diverse tissues, including the brain, but may bind strongly to proteins and accumulate in fat. They are often metabolized to more polar, excretable forms; extreme lipophilicity can reduce solubility and increase risk of off-target effects and toxicity.

In medicine and environmental science, lipophilicity informs drug design, risk assessment, and formulation strategies. Lipinski's Rule of Five, for example, uses logP thresholds as a guideline for oral bioavailability. Lipophilic substances also tend to bioaccumulate in organisms and persist in the environment, guiding safety and regulatory considerations.