Pamoic acid disodium is a potent GPR35 agonist/activator with EC50 of 79 nM. Pamoic acid disodium induces GPR35 internalization and activates ERK1/2 with EC50s of 22 nM and 65 nM respectively. Pamoic acid disodium effectively recruits β-arrestin2 to GPR35 and has antinociceptive effects.

Physicochemical Properties

Molecular Formula	C23H14NA2O6
Molecular Weight	432.33
Exact Mass	432.058
CAS #	6640-22-8
Related CAS #	130-85-8 (Parent)
PubChem CID	54676156
Appearance	Off-white to light yellow solid powder
Boiling Point	642.7ºC at 760 mmHg
Melting Point	300 °C
Flash Point	356.5ºC
LogP	1.722
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	4
Heavy Atom Count	31
Complexity	569
Defined Atom Stereocenter Count	0
InChi Key	YGLLICRFEVEWOZ-UHFFFAOYSA-L
InChi Code	InChI=1S/C23H16O6.2Na/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);;/q;2*+1/p-2
Chemical Name	disodium;3-carboxy-1-[(3-carboxy-2-oxidonaphthalen-1-yl)methyl]naphthalen-2-olate
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	EC50: 79 nM (GPR35), 65 nM (ERK1/2)[1]
ln Vitro	Pamoic acid (0.1 nM-0.1 mM) stimulates GPR35a internalization with an EC50 value of 22 nM[1]. Pamoic acid (0-10 μM) promotes ERK1/2 activation [1].
ln Vivo	In the abdominal contraction test, dose-related antinociceptive effects are induced by pamoic acid disodium (0-100 mg/kg; sc; once)[1].
Cell Assay	Western Blot Analysis[1] Cell Types: U2OS cells Tested Concentrations: 1, 10, 100 nM and 1, 10 μM Incubation Duration: 15 min Experimental Results: A concentration-dependent activation of ERK1/2 was observed with an EC50 of 65 nM.
Animal Protocol	Animal/Disease Models: Swiss-Webster mice (30–35 g)[1] Doses: 25, 50, and 100 mg/kg Route of Administration: subcutaneous (sc) injection, once Experimental Results: Elicited dose-related antinociception, the dose causing 50% antinociception being 40.5 mg /kg.
References	[1]. Targeting of the orphan receptor GPR35 by pamoic acid: a potent activator of extracellular signal-regulated kinase and β-arrestin2 with antinociceptive activity. Mol Pharmacol. 2010 Oct;78(4):560-8.
Additional Infomation	See also: Disodium pamoate monohydrate (annotation moved to).

Solubility Data

Solubility (In Vitro)

DMSO: 100 mg/mL (231.30 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 7.5 mg/mL (17.35 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 75.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 7.5 mg/mL (17.35 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 75.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.3130 mL	11.5652 mL	23.1305 mL
	5 mM	0.4626 mL	2.3130 mL	4.6261 mL
	10 mM	0.2313 mL	1.1565 mL	2.3130 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.