Search results
Results from the WOW.Com Content Network
While the mechanisms by which a formulation affects bioavailability and bioequivalence have been extensively studied in drugs, formulation factors that influence bioavailability and bioequivalence in nutritional supplements are largely unknown. [21]
First-pass metabolism may occur in the liver (for propranolol, lidocaine, clomethiazole, and nitroglycerin) or in the gut (for benzylpenicillin and insulin). [4] The four primary systems that affect the first pass effect of a drug are the enzymes of the gastrointestinal lumen, [5] gastrointestinal wall enzymes, [6] [7] [8] bacterial enzymes [5] and hepatic enzymes.
Drug metabolism is the metabolic breakdown of drugs by living organisms, usually through specialized enzymatic systems. More generally, xenobiotic metabolism (from the Greek xenos "stranger" and biotic "related to living beings") is the set of metabolic pathways that modify the chemical structure of xenobiotics, which are compounds foreign to an organism's normal biochemistry, such as any drug ...
Cell membranes may act as barriers to some drugs. They are essentially lipid bilayers which form semipermeable membranes. Pure lipid bilayers are generally permeable only to small, uncharged solutes. Hence, whether or not a molecule is ionized will affect its absorption, since ionic molecules are charged. Solubility favors charged species, and ...
Drug delivery to the brain is the process of passing therapeutically active molecules across the blood–brain barrier into the brain.This is a complex process that must take into account the complex anatomy of the brain as well as the restrictions imposed by the special junctions of the blood–brain barrier.
Factors that affect distribution [ edit ] There are many factors that affect a drug's distribution throughout an organism, but Pascuzzo [ 1 ] considers that the most important ones are the following: an organism's physical volume, the removal rate and the degree to which a drug binds with plasma proteins and / or tissues.
The relationship between the biological and plasma half-lives of a substance can be complex depending on the substance in question, due to factors including accumulation in tissues, protein binding, active metabolites, and receptor interactions. [7]
This second process is where the absorbed food reaches the cells via the liver. Most foods are composed of largely indigestible components depending on the enzymes and effectiveness of an animal's digestive tract. The most well-known of these indigestible compounds is cellulose; the basic chemical polymer in the