Editing Bioavailability (section)

== Definitions ==

=== In pharmacology ===

Bioavailability is a term used to describe the percentage of an administered dose of a xenobiotic that reaches the systemic circulation.<ref>{{cite book|last1=Shargel|first1=L.|last2=Yu|first2=A. B.|date=1999|title=Applied Biopharmaceutics & Pharmacokinetics|edition=4th|location=New York|publisher=McGraw-Hill|isbn=978-0-8385-0278-5|url-access=registration|url=https://archive.org/details/appliedbiopharma0000shar_a7d4}}{{page needed|date=February 2013}}</ref>
It is denoted by the letter ''f'' (or, if expressed in percent, by ''F'').

=== In nutritional science ===

In [[nutritional science]], which covers the intake of nutrients and non-drug dietary ingredients, the concept of bioavailability lacks the well-defined standards associated with the pharmaceutical industry. The pharmacological definition cannot apply to these substances because utilization and absorption is a function of the nutritional status and physiological state of the subject,<ref>{{cite journal |pmid=11285351 |year=2001 |last1=Heaney |first1=Robert P. |title=Factors Influencing the Measurement of Bioavailability, Taking Calcium as a Model |volume=131 |issue=4 Suppl |pages=1344–1348S |journal=The Journal of Nutrition |doi=10.1093/jn/131.4.1344S |doi-access=free }}</ref> resulting in even greater differences from individual to individual (inter-individual variation). Therefore, bioavailability for dietary supplements can be defined as the proportion of the administered substance capable of being absorbed and available for use or storage.<ref name="Srinivasan">{{cite journal |pmid=11285352 |year=2001 |last1=Srinivasan |first1=V. Srini |title=Bioavailability of Nutrients: A Practical Approach to In Vitro Demonstration of the Availability of Nutrients in Multivitamin-Mineral Combination Products |volume=131 |issue=4 Suppl |pages=1349–1350S |journal=The Journal of Nutrition |doi=10.1093/jn/131.4.1349S |doi-access=free }}</ref>

In both [[pharmacology]] and nutrition sciences, bioavailability is measured by calculating the [[Area under the curve (pharmacokinetics)|area under curve]] (AUC) of the drug concentration time profile.

===In environmental sciences or science===

Bioavailability is the measure by which various substances in the environment may enter into living organisms.  It is commonly a limiting factor in the production of crops (due to solubility limitation or absorption of plant nutrients to soil colloids) and in the removal of toxic substances from the food chain by microorganisms (due to sorption to or partitioning of otherwise degradable substances into inaccessible phases in the environment). A noteworthy example for agriculture is plant phosphorus deficiency induced by precipitation with iron and aluminum phosphates at low [[soil pH]] and precipitation with calcium phosphates at high soil pH.<ref>{{cite journal |doi=10.1023/A:1013351617532 |year=2001 |last1=Hinsinger |first1=Philippe |title=Bioavailability of soil inorganic P in the rhizosphere as affected by root-induced chemical changes: a review |journal=Plant and Soil |volume=237 |issue=2 |pages=173–195|s2cid=8562338 }}</ref> Toxic materials in soil, such as lead from paint may be rendered unavailable to animals ingesting contaminated soil by supplying phosphorus fertilizers in excess.<ref>{{cite journal |doi=10.1021/es00046a007 |title=In situ lead immobilization by apatite |year=1993 |last1=Ma |first1=Qi-Ying |last2=Traina |first2=Samuel J. |last3=Logan |first3=Terry J. |last4=Ryan |first4=James A. |journal=Environmental Science & Technology |volume=27 |issue=9 |pages=1803–1810|bibcode=1993EnST...27.1803M }}</ref> Organic pollutants such as solvents or pesticides<ref>{{cite book|last1=Sims|first1=G.K. |first2=M. |last2=Radosevich |first3=X.-T. |last3=He |first4=S. J. |last4=Traina|contribution=The effects of sorption on the bioavailability of pesticides|editor-first=W. B. |editor-last=Betts |title=Biodegradation of Natural and Synthetic Materials |publisher=Springer |location=London|year=1991|pages=119–137}}</ref>  may be rendered unavailable to microorganisms and thus persist in the environment when they are adsorbed to soil minerals<ref>{{cite journal |doi=10.1002/etc.5620190904 |title=Effects of sorption on the biodegradation of 2-methylpyridine in aqueous suspensions of reference clay minerals |year=2000 |last1=O'Loughlin |first1=Edward J. |last2=Traina |first2=Samuel J. |last3=Sims |first3=Gerald K. |journal=Environmental Toxicology and Chemistry |volume=19 |issue=9 |pages=2168–2174|s2cid=98654832 }}</ref> or partition into hydrophobic organic matter.<ref>{{cite journal |doi=10.1002/(SICI)1096-9063(199905)55:5<598::AID-PS962>3.0.CO;2-N |title=Factors controlling degradation of pesticides in soil |year=1999 |last1=Sims |first1=Gerald K. |last2=Cupples |first2=Alison M. |journal=Pesticide Science |volume=55 |issue=5 |pages=598–601}}</ref>