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HandWiki. Biological Half-life. Encyclopedia. Available online: https://encyclopedia.pub/entry/35021 (accessed on 24 September 2026).
HandWiki. Biological Half-life. Encyclopedia. Available at: https://encyclopedia.pub/entry/35021. Accessed September 24, 2026.
HandWiki. "Biological Half-life" Encyclopedia, https://encyclopedia.pub/entry/35021 (accessed September 24, 2026).
HandWiki. (2022, November 17). Biological Half-life. In Encyclopedia. https://encyclopedia.pub/entry/35021
HandWiki. "Biological Half-life." Encyclopedia. Web. 17 November, 2022.
Biological Half-life
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The content is sourced from: https://handwiki.org/wiki/Biology:Biological_half-life

The biological half-life of a biological substance is the time it takes for half to be removed by biological processes. This concept is used when the rate of removal is roughly exponential. It is often denoted by the abbreviation [math]\displaystyle{ t_{\frac{1}{2}} }[/math]. This is used to measure the removal of things such as metabolites, drugs, and signalling molecules from the body. Typically, the biological half-life refers to the body's natural cleansing through the function of the liver and through the excretion of the measured substance through the kidneys and intestines. In a medical context, half-life explicitly describes the time it takes for the blood plasma concentration of a substance to halve (plasma half-life) its steady-state when circulating in the full blood of an organism. This measurement is useful in medicine and pharmacology because it helps determine how much of a drug needs to be taken and how frequently it needs to be taken if a certain average amount is needed constantly. In contrast, the stability of a substance direct in plasma is described with plasma stability that is essential to ensure accurate analysis of drugs in plasma and for Drug discovery. 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.

plasma stability blood plasma stability

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