Drugs are present in the bloodstream in either bound to albumin or in the free state. Explain why equilibrium between the bound and unbound state is required for proper drug function. What is the role of the bound state

Equilibrium between bound and unbound state is necessary for proper drug function, depending on the target areas of the drug therapy.

Explanation:

Plasma protein binding is the degree to which medical drugs are attached to the blood protein, which in most cases is albumin. the efficacy of drug therapy is affected by the extent to which the drug is either bound or unbound to proteins in the bloodstream.

Role of bound state: Unbound drugs dissociate from the bloodstrream and can easily transverse the cell membranes or be diffused, which translates to absorption by the liver and other tissues and directly increases the rate of drug metabolism requirement. Hence the bound state keeps these drugs in the blood and body for a longer period of time.

Consequently, anti-infective drugs targeting the liver and other tissues, must be able to diffuse through capillary membranes to reach its target outside the plasma to the infection site typically located outside plasma.

Subsequently, the law of mass action dictates that the binding of drugs to plasma proteins is reversible, and equilibrium between the protein-bound and unbound drug is quickly established.

WHY EQUILIBRIUM BETWEEN BOUND AND UNBOUND STATE IS REQUIRED FOR PROPER DEUG FUNCTION.

A drug in blood exists in two forms: bound and unbound. Depending on a specific drug's affinity for plasma protein, a proportion of the drug may become bound to plasma proteins, with the remainder being unbound. If the protein binding is reversible, then a chemical equilibrium will exist between the bound and unbound states.

Notably, it is the unbound fraction which exhibits pharmacologic effects. For instance, if a drug fraction bound is 90%. That means that 90% of the drug in the blood is bound to protein and the remaining 10% is active and will eventually be excreted.

ROLE OF THE BOUND STATE.

The bound portion may act as a reservoir or depot from which the drug is slowly released as the unbound form. Since the unbound form is being metabolized and/or excreted from the body, the bound fraction will be released in order to maintain equilibrium.