Medication Bioavailability Measure
A Medication Bioavailability Measure is a Medication Absorption Measure that estimates the fraction of a medication that is absorbed or used by a body.
- AKA: Bioavailability.
- Context:
- It can measure the fraction of a medication that reaches the circulatory system.
- It can range from being a Absolute Bioavailability Measure to being a Relative Bioavailability Measure.
- Example(s):
- Bioavailability is the ratio of the area calculated for oral route of administration to the intravenous route of administration. It is determined by comparing the plasma levels of a drug after administration with plasma drug level achieved by I/V injection.
$Bioavailability = \dfrac{AUC (oral)}{AUC (I/V)} \times 100$
where AUC is the area under the curve (In: HowMed, 2021).
- …
- Bioavailability is the ratio of the area calculated for oral route of administration to the intravenous route of administration. It is determined by comparing the plasma levels of a drug after administration with plasma drug level achieved by I/V injection.
- Counter-Example(s):
- See: Clinical Trial, Dietary Supplements, Pharmacology, Medication, Systemic Circulation, Intravenous, Route of Administration, First-Pass Metabolism, Standard Deviation.
References
2021a
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Bioavailability Retrieved:2021-11-21.
- In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation.[1]
By definition, when a medication is administered intravenously, its bioavailability is 100%. [2] However, when a medication is administered via routes other than intravenous, its bioavailability is generallylower than that of intravenous due to intestinal endothelium 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 formulation to the AUC for the intravascular formulation.[3] AUC is used because AUC is proportional to the dose that has entered the systemic circulation.[4] Bioavailability of a drug is an average value; to take population variability into account, deviation range is shown as ±.[3] To ensure that the drug taker who has poor absorption is dosed appropriately, the bottom value of the deviation range is employed to represent real bioavailability and to calculate the drug dose needed for the drug taker to achieve systemic concentrations similar to the intravenous formulation.[3] To dose without knowing the drug taker's absorption rate, the bottom value of the deviation range is used in order to ensure the intended efficacy, unless the drug is associated with a narrow therapeutic window.[3] For dietary supplements, herbs and other nutrients in which the route of administration is nearly always oral, bioavailability generally designates simply the quantity or fraction of the ingested dose that is absorbed. [5] [6]
- In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation.[1]
- ↑ Hebert, Mary F. (2013). “Impact of Pregnancy on Maternal Pharmacokinetics of Medications". Clinical Pharmacology During Pregnancy. Elsevier. pp. 17–39. doi:10.1016/b978-0-12-386007-1.00003-9. ISBN 978-0-12-386007-1.
- ↑ Griffin, J. P. (7 December 2009). The Textbook of Pharmaceutical Medicine (6th ed.). Jersey: BMJ Books. ISBN 978-1-4051-8035-1.
- ↑ 3.0 3.1 3.2 3.3 Davis, Jennifer L. (2018). “Pharmacologic Principles". Equine Internal Medicine. Elsevier. pp. 79–137. doi:10.1016/b978-0-323-44329-6.00002-4. ISBN 978-0-323-44329-6.
- ↑ Johanson, G. (2010). “Modeling of Disposition". Comprehensive Toxicology. Elsevier. pp. 153–177. doi:10.1016/b978-0-08-046884-6.00108-1. ISBN 978-0-08-046884-6.
- ↑ Heaney, Robert P. (2001). “Factors Influencing the Measurement of Bioavailability, Taking Calcium as a Model". The Journal of Nutrition. 131 (4): 1344S–8S. doi:10.1093/jn/131.4.1344S. PMID 11285351.
- ↑ SANDSTEAD, HAROLD H.; AU, WILLIAM (2007). “Zinc**Dr. Carl-Gustaf Elinder was the author of this chapter in the 2nd edition of the Handbook on Toxicology of Metals; his text provided guidance.". Handbook on the Toxicology of Metals. Elsevier. pp. 925–947. doi:10.1016/b978-012369413-3/50102-6. ISBN 978-0-12-369413-3. Bioavailability is the major factor affecting dietary requirements (Sandstrom, 1997). Flesh foods facilitate bioavailability, although indigestible Zn-binding ligands decrease bioavailability (Mills, 1985)."
2021b
- (HowMed, 2021) ⇒ http://howmed.net/pharmacology/bioavailability-of-drugs/ Retrieved:2021-11-21
- QUOTE: Fraction of the dose of a drug contained in any dosage form that reaches the systemic circulation in unchanged or active form administered through any route is known as bioavailability.
Drugs injected using intravenous route of administration have 100% bioavailability, while others have much less bioavailability, because:
- All of the drug may not be adsorbed
- Metabolism of the drug might occur before reaching the site of action
- QUOTE: Fraction of the dose of a drug contained in any dosage form that reaches the systemic circulation in unchanged or active form administered through any route is known as bioavailability.
2021c
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Glossary_of_clinical_research Retrieved:2021-11-21.
- QUOTE: Bioavailable
- The ability of a drug or other substance to be absorbed and used by the body. Orally bioavailable means that a drug or other substance that is taken by mouth can be absorbed and used by the body. (NCI)
- QUOTE: Bioavailable
2021d
- (NIH, 2021) ⇒ https://www.cancer.gov/publications/dictionaries/cancer-terms/def/bioavailable Retrieved:2021-11-21.
- QUOTE: bioavailable
- The ability of a drug or other substance to be absorbed and used by the body. Orally bioavailable means that a drug or other substance that is taken by mouth can be absorbed and used by the body.
- QUOTE: bioavailable