A Study on Drug interaction with certain plasma Proteins and their subtitutes

Drug binding to various serum and tissue proteins can influence the therapeutic, pharmacodynamic and toxic logic actions of these drugs. Protein binding may also exert profound effect on the drug distribution. The protein-drug complex may act as a transport system to carry drug to the sites, of action; this transport is extremely important for drugs that exhibit, low solubility in the water portion of the plasma. Protein binding slows, the disappearance of free drug from the plasma into tissues by decreasing the concentration gradient. It also provides a source of free drug to replace that removed by various distribution and elimination processes. ,The binding equilibrium is often described by an association constant or constants together with the number of sites exhibiting each association constant. Such information is useful in establishing a proper dosage regimen. It is also of importance when .two or more drugs, that strongly bind to protein and compete for the same binding sites, are administered concurrently. Higher free drug concentrations are thereby produced and may precipitate a toxic response. Such increase in pharmacological activity of the displaced drug often necessitates an adjustment in dosage. The binding to human serum albumin of a new drug should be examined, especially if the drug is an acidic molecule, because competitive binding with serum protein among acidic .drugs has been shown to be particularly significant