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[2] [3] However, when a medication is administered via routes other than intravenous, its bioavailability is lower due to intestinal epithelium absorption and first-pass metabolism. Thereby, mathematically, bioavailability equals the ratio of comparing the area under the plasma drug concentration curve versus time (AUC) for the extravascular ...
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.
Factors that affect absorption include: The way a drug product is designed and manufactured; Its physical and chemical properties; Other ingredients it contains; The physiologic characteristics of the person taking the drug; How the drug is stored [11]
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.
Pulmonary drug delivery is mainly utilized for topical applications in the lungs, such as the use of inhaled beta-agonists, corticosteroids and anticholinergic agents for the treatment of asthma and COPD, the use of inhaled mucolytics and antibiotics for the treatment of cystic fibrosis (CT) and respiratory viral infections, [1] and the use of inhaled prostacyclin analogs for the treatment of ...
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]
Eczema, also known as atopic dermatitis, can cause a variety of symptoms ranging from scaly, dry skin to itchy rashes and oozing patches, depending on the severity of the flare-up.
Temperature may affect metabolic transformation, and bioenergetics. An example of this is the movement of the organism may change as well as rates of excretion. [15] If a contaminant is ionic, the change in pH that is influenced by a change in temperature may also influence the bioavailability [1]