What is "pamoic acid"

n. (context organic compound English) A derivative of naphthoic acid, whose salt form can be used in pharmacology to increase the solubility of a drug in water.

Pamoic acid, also called embonic acid, is a naphthoic acid derivative. Salts and esters of pamoic acid are known as pamoates or embonates. It can be prepared by the reaction of 2-hydroxy-3-naphthoic acid with formaldehyde.

In pharmacology, the salt form of pamoic acid (pamoate ion) can be used as a counter ion of a drug compound to increase the solubility of the drug in water. The presence of multiple oxygen atoms enables significant hydrogen bonding to occur. Hydrogen bonds facilitate the dissolution of compounds in water.

Pamoic acid has agonist activity for the orphan G protein-coupled receptor GPR35 by which it activates ERK and beta-arrestin2, and causes antinociceptive activity. Although (like other drug salts) it has been considered an inactive compound by the FDA, these recent data suggest that its permitted uses may need to be reexamined.