Pamoic acid

Pamoic acid^[1]^[2]
Names

IUPAC name 4-[(3-Carboxy-2-hydroxynaphthalen-1-yl)methyl]-3-hydroxynaphthalene-2-carboxylic acid
Other names Embonic acid
Identifiers
Beilstein Reference	901319
CAS Registry Number	130-85-8^Y
ChEBI	CHEBI:50186
ChEMBL	ChEMBL177880^Y
ChemSpider	8228^Y
EC number	204-998-0
InChI InChI=1S/C23H16O6/c24-20-16(14-7-3-1-5-12(14)9-18(20)22(26)27)11-17-15-8-4-2-6-13(15)10-19(21(17)25)23(28)29/h1-10,24-25H,11H2,(H,26,27)(H,28,29)^Y Key: WLJNZVDCPSBLRP-UHFFFAOYSA-N^Y
Jmol-3D images	Image Image
MeSH	Pamoic+acid
PubChem	8546
RTECS number	QL2180000
SMILES OC(=O)C1=CC2=CC=CC=C2C(CC2=C(O)C(=CC3=CC=CC=C23)C(O)=O)=C1O C1=CC=C2C(=C1)C=C(C(=C2CC3=C(C(=CC4=CC=CC=C43)C(=O)O)O)O)C(=O)O
UNII	7RRQ8QZ38N^Y
Properties
Molecular formula	C₂₃H₁₆O₆
Molar mass	388.37 g·mol⁻¹
Melting point	≥300 °C
log P	6.169
Acidity (pK_a)	2.675
Hazards
Main hazards	Causes skin irritation Causes serious eye irritation May cause respiratory irritation
EU classification	Xi
R-phrases	R36/37/38
S-phrases	S26 S36
Except where noted otherwise, data is 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. 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.

References

↑ Merck Index, 12th Edition, 7136.
↑ 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.
↑ 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

Neubig, Richard R (2010). "Mind your salts: when the inactive constituent isn't". Molecular Pharmacology 78 (4): 558–9. doi:10.1124/mol.110.067645. PMID 20651116.