How does tissue binding affect drug distribution?
For a drug that is highly tissue-bound, very little drug remains in the circulation; thus, plasma concentration is low and volume of distribution is high. Drugs that remain in the circulation tend to have a low volume of distribution.
In what way does tissue storage affects the action of drug?
Accumulation of drugs in tissues or body compartments can prolong drug action because the tissues release the accumulated drug as plasma drug concentration decreases.
What does drug distribution depend on?
The distribution of a drug between tissues is dependent on vascular permeability, regional blood flow, cardiac output and perfusion rate of the tissue and the ability of the drug to bind tissue and plasma proteins and its lipid solubility.
How are drugs distributed through the body?
The average circulation time of blood is 1 minute. As the blood recirculates, the drug moves from the bloodstream into the body’s tissues. Once absorbed, most drugs do not spread evenly throughout the body.
What is tissue permeability of drug?
Tissue permeability (κ): Tissue permeability characterizes the capacity of brain tissue to enable substances’ transport through the tissue extracellular matrix. It depends on the local tissue microstructure, arrangement of nerve fibers, etc.
Which drugs Cannot be filtered through glomerulus?
Which drugs cannot be filtered through glomerulus? Explanation: Drugs that are bound to plasma behave as macromolecules don’t get filtered through the glomerulus. Unbound free drug which are less than 300 Dalton get filtered by the glomerulus. 12.
How are drugs absorbed distributed metabolized and eliminated in the body?
Following administration, the drug must be absorbed and then distributed, usually via vessels of the circulatory and lymphatic systems; in addition to crossing membrane barriers, the drug must survive metabolism (primarily hepatic) and elimination (by the kidney and liver and in the feces).
Why do drugs need to be soluble?
Solubility is one of the important parameters to achieve desired concentration of drug in systemic circulation for achieving required pharmacological response [12]. These poorly water soluble drugs having slow drug absorption leads to inadequate and variable bioavailability and gastrointestinal mucosal toxicity.
What is the blood brain barrier?
The blood-brain barrier (BBB) is a crucial immunological feature of the human central nervous system (CNS). Composed of many cell types, the BBB is both a structural and functional roadblock to microorganisms, such as bacteria, fungi, viruses or parasites, that may be circulating in the bloodstream.
What is non linear pharmacokinetics?
Nonlinear pharmacokinetics (in other words, time or dose dependences in pharmacokinetic parameters) can arise from factors associated with absorption, first-pass metabolism, binding, excretion and biotransformation. Often, in these cases, parameters based on free drug concentration appear linear.
Where are drugs secreted in the nephron?
Free drug is filtered at the glomerulus and it can also be actively secreted into the proximal tubule.