Pamoic acid

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Pamoic acid[1][2]
Structural formula of pamoic acid
IUPAC name
4-[(3-Carboxy-2-hydroxynaphthalen-1-yl)methyl]-3-hydroxynaphthalene-2-carboxylic acid
Other names
Embonic acid
130-85-8 YesY
ChEMBL ChEMBL177880 YesY
ChemSpider 8228 YesY
EC Number 204-998-0
Jmol interactive 3D Image
MeSH Pamoic+acid
PubChem 8546
RTECS number QL2180000
Molar mass 388.38 g·mol−1
Melting point ≥300 °C
log P 6.169
Acidity (pKa) 2.675
Main hazards Causes skin irritation

Causes serious eye irritation
May cause respiratory irritation

Irritant Xi
R-phrases R36/37/38
S-phrases S26 S36
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.[3] The presence of multiple oxygen atoms enables significant hydrogen bonding to occur. Hydrogen bonds facilitate the dissolution of compounds in water.

It was demonstrated that 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.[citation needed] Although (like other drug salts) it has been considered an inactive compound by the FDA, these recent data suggest that its use may be reexamined.[citation needed]


  1. ^ Merck Index, 12th Edition, 7136.
  2. ^ Zhao, P.; Sharir, H.; Kapur, A.; Cowan, A.; Geller, E. B.; Adler, M. W.; Seltzman, H. H.; Reggio, P. H.; et al. (2010). "Targeting of the Orphan Receptor GPR35 by Pamoic Acid: A Potent Activator of Extracellular Signal-Regulated Kinase and -Arrestin2 with Antinociceptive Activity". Molecular Pharmacology 78 (4): 560–8. doi:10.1124/mol.110.066746. PMC 2981393. PMID 20826425. 
  3. ^ Saesmaa, T; Tötterman, AM (1990). "Dissolution studies on ampicillin embonate and amoxycillin embonate". Journal of pharmaceutical and biomedical analysis 8 (1): 61–5. doi:10.1016/0731-7085(90)80007-c. PMID 2102266. 

External links[edit]