Drug-protein binding plays a key role in determining the pharmacokinetics of a drug. The distribution and protein binding ability of a drug changes over a lifetime, and are important considerations during pregnancy and lactation. Although proteins are a significant fraction in plasma composition, they also exist beyond the bloodstream and bind with drugs in the skin, tissues or organs. Protein binding influences the bioavailability and distribution of active compounds, and is a limiting factor in the passage of drugs across biological membranes and barriers: drugs are often unable to cross membranes mainly due to the high molecular mass of the drug-protein complex, thus resulting in the accumulation of the active compounds and a significant reduction of their pharmacological activity. This review describes the consequences of drug-protein binding on drug transport across physiological barriers, whose role is to allow the passage of essential substances-such as nutrients or oxygen, but not of xenobiotics. The placental barrier regulates passage of xenobiotics into a fetus and protects the unborn organism. The blood-brain barrier is the most important barrier in the entire organism and the skin separates the human body from the environment.

中文翻译：

---

生物屏障以及蛋白质结合对药物通过它们的影响。

药物-蛋白质结合在确定药物的药代动力学中起关键作用。药物的分布和蛋白质结合能力会在一生中发生变化，这是怀孕和哺乳期间的重要考虑因素。尽管蛋白质是血浆成分的重要组成部分，但它们也存在于血流之外，并与皮肤，组织或器官中的药物结合。蛋白质结合会影响活性化合物的生物利用度和分布，并且是药物穿过生物膜和屏障的通道中的限制因素：药物通常无法通过膜，主要是因为药物-蛋白质复合物的分子量很高，因此活性化合物的积聚和显着降低其药理活性。这篇综述描述了药物-蛋白质结合对跨生理障碍的药物转运的后果，其作用是允许必需物质（如营养素或氧气）通过，而异种生物则不然。胎盘屏障调节异生素进入胎儿的通道并保护未出生的生物。血脑屏障是整个生物体中最重要的屏障，皮肤使人体与环境隔离。