Editing Pseudoephedrine (section)

====Distribution====
Pseudoephedrine, due to its lack of [[Chemical polarity|polar]] [[Phenols|phenolic]] [[functional group|group]]s, is relatively [[lipophilic]].<ref name="ChuaBenrimojTriggs1989" /> This is a property it shares with related sympathomimetic and decongestant agents like [[ephedrine]] and [[phenylpropanolamine]].<ref name="ChuaBenrimojTriggs1989" /> These agents are widely [[distribution (pharmacology)|distributed]] throughout the body and cross the [[blood–brain barrier]].<ref name="ChuaBenrimojTriggs1989" /> However, it is said that pseudoephedrine and phenylpropanolamine cross the blood-brain barrier only to some extent and that pseudoephedrine has limited [[central nervous system]] activity, suggesting that it is partially [[peripherally selective drug|peripherally selective]].<ref name="ODonnell1995" /><ref name="BouchardWeberGeiger2002" /> The blood-brain barrier permeability of pseudoephedrine, ephedrine, and phenylpropanolamine is reduced compared to other [[substituted amphetamine|amphetamines]] due to the presence of a [[hydroxyl group]] at the β carbon which decreases their [[lipophilicity]].<ref name="BouchardWeberGeiger2002">{{cite journal | vauthors = Bouchard R, Weber AR, Geiger JD | title = Informed decision-making on sympathomimetic use in sport and health | journal = Clin J Sport Med | volume = 12 | issue = 4 | pages = 209–224 | date = July 2002 | pmid = 12131054 | doi = 10.1097/00042752-200207000-00003 | url = }}</ref> As such, they have a greater ratio of peripheral cardiovascular to central psychostimulant effect.<ref name="BouchardWeberGeiger2002" /> Besides entering the brain, these substances also cross the [[placenta]] and enter [[breast milk]].<ref name="ChuaBenrimojTriggs1989" />

The [[plasma protein binding]] of pseudoephedrine has been reported to be approximately 21 to 29%.<ref name="VolppHolzgrabe2019" /><ref name="Schmidt2023" /> It is bound to [[orosomucoid|α<sub>1</sub>-acid glycoprotein]] (AGP) and [[human serum albumin|albumin]] (HSA).<ref name="VolppHolzgrabe2019" /><ref name="Schmidt2023" />