Editing Permethrin (section)

== Pharmacokinetics ==

Permethrin is a chemical categorized in the pyrethroid insecticide group.<ref name=PermGen/> The chemicals in the pyrethroid family are created to emulate the chemicals found in the [[chrysanthemum]] flower.<ref name=PermGen/>

=== Absorption ===
Absorption of topical permethrin is minimal. One ''in vivo'' study demonstrated 0.5% absorption in the first 48 hours based upon excretion of urinary metabolites.<ref name="van der Rhee 1989 170–3">{{cite journal | vauthors = van der Rhee HJ, Farquhar JA, Vermeulen NP | title = Efficacy and transdermal absorption of permethrin in scabies patients | journal = Acta Dermato-Venereologica | volume = 69 | issue = 2 | pages = 170–173 | date = 1989 | pmid = 2564238 }}</ref>

=== Distribution ===
Distribution of permethrin has been studied in rat models, with highest amounts accumulating in fat and the brain.<ref>{{cite journal | vauthors = Tornero-Velez R, Davis J, Scollon EJ, Starr JM, Setzer RW, Goldsmith MR, Chang DT, Xue J, Zartarian V, DeVito MJ, Hughes MF | title = A pharmacokinetic model of cis- and trans-permethrin disposition in rats and humans with aggregate exposure application | journal = Toxicological Sciences | volume = 130 | issue = 1 | pages = 33–47 | date = November 2012 | pmid = 22859315 | doi = 10.1093/toxsci/kfs236 | s2cid = 20980566 | doi-access = free }}</ref> This can be explained by the lipophilic nature of the permethrin molecule.{{citation needed|date=December 2022}}

=== Metabolism ===
Metabolism of permethrin occurs mainly in the liver, where the molecule undergoes oxidation by the cytochrome P450 system, as well as hydrolysis, into non-toxic metabolites.<ref name="van der Rhee 1989 170–3" />

=== Excretion ===
The elimination of permethrin and its metabolites occurs mainly through urinary excretion, but also through feces. In rats, the excretion half-life is 12 hours for plasma and 9 to 23 hours for certain nervous tissue.<ref name="npic"/>