Plasma protein binding

As protein binding, and plasma protein binding called (ppb) or plasma protein binding (PEB), the reversible binding of substances of protein components of the blood ( plasma proteins, erythrocyte proteins ), or the body tissue is indicated. At this protein binding, various forms of chemical bonds may be involved, including ionic bonds, hydrogen bonds, dipole- dipole interactions and hydrophobic interactions. Protein binding has the consequence that the bound substances, including drugs and various endogenous substances, their normal effect or only decreased exercise, because how else they can not react with the environment. The bound proteins by percentage of a substance is thus pharmacologically inactive. Small molecules gain by binding a greatly extended half-life, are so excreted only very slowed over the kidney.

The substances which are bound to a large extent in the plasma of proteins include, for example, the drugs sulfonamides, sulfonylureas, acetylsalicylic acid, phenylbutazone, warfarin, and the endogenous substances bilirubin and calcium.

The total amount of a substance that can be bonded is limited by the capacity of the proteins. Through mutual displacement from plasma protein binding substances can mutually their actual effective (since unbound ) increased concentration in the blood. For this reason, for instance, enhance the sulfonamides neonatal jaundice by displacement of bilirubin from albumin and is therefore contraindicated in neonates. On administration of various drugs based drug-drug interactions in the occurrence of adverse drug reactions (side effects) can lead to this principle.

• Pharmacology