Distribution: Tissue Binding and StorageE.g. Usually with albumin a plasma protein and sometimes with fat tissueoOnly free or unbound drug molecules can act on a receptoro‘bound’ drug is unable to bind with a cell receptor so cannot actHow is drug binding and storage significant in drug therapy?

Drug binding and storage play a significant role in drug therapy. Here's why:

1. Distribution: When a drug enters the bloodstream, it can bind to plasma proteins, such as albumin, or be stored in fat tissue. This binding and storage affect the distribution of the drug throughout the body.

2. Free vs. Bound Drug: Only free or unbound drug molecules can interact with cell receptors and exert their therapeutic effects. Bound drugs, which are attached to plasma proteins or stored in fat tissue, cannot bind to receptors and therefore cannot act on them.

3. Therapeutic Effect: The ability of a drug to bind to its target receptors is crucial for achieving the desired therapeutic effect. If a significant portion of the drug is bound or stored, it may reduce the concentration of free drug available to interact with receptors, potentially diminishing the therapeutic response.

4. Drug Interactions: Drug binding and storage can also influence drug interactions. If two drugs compete for binding to the same plasma protein, one drug may displace the other, leading to altered drug concentrations and potentially affecting the therapeutic outcome.

5. Duration of Action: Drug binding and storage can affect the duration of action of a drug. Bound drugs are released slowly over time, providing a sustained release of the drug and prolonging its effects.

Understanding the binding and storage of drugs is essential in drug therapy as it helps determine the optimal dosage, dosing frequency, and potential drug interactions. By considering these factors, healthcare professionals can ensure that the drug reaches its target receptors and exerts its intended therapeutic effects.