A-438079 HCl is a novel, potent, and selective P2X7 receptor antagonist with pIC50 of 6.9. A438079 protects against acetaminophen-induced liver injury by inhibiting p450 isoenzymes, not by inflammasome activation. A-438079 reduced electrographic and clinical seizure severity during status epilepticus and reduced seizure-induced neuronal death in the neocortex. Blockade of P2X(7) receptors may represent a novel protective strategy for striatal DA terminals in Parkinson's disease.

Physicochemical Properties

Molecular Formula	C13H10CL3N5
Molecular Weight	342.6110
Exact Mass	341
CAS #	899507-36-9
Related CAS #	A 438079 hydrochloride;899431-18-6
PubChem CID	11673921
Appearance	White to off-white solid powder
LogP	3.892
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	3
Heavy Atom Count	20
Complexity	319
Defined Atom Stereocenter Count	0
InChi Key	MBTJFFMIPPMRGR-UHFFFAOYSA-N
InChi Code	InChI=1S/C13H9Cl2N5.ClH/c14-11-5-1-4-10(12(11)15)13-17-18-19-20(13)8-9-3-2-6-16-7-9;/h1-7H,8H2;1H
Chemical Name	3-[[5-(2,3-dichlorophenyl)tetrazol-1-yl]methyl]pyridine;hydrochloride
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
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

ln Vitro	A 438079 inhibits BzATP-10 μM-induced fluctuations in intracellular calcium concentration in 1321N1 cells that express the rat P2X7 receptor stable, with an IC50 of 321 nM. At doses up to 100 μM, 438079 is likewise selective for the P2X7 receptor [1].
ln Vivo	In neuropathic rats, 438079 (80 μmol/kg, i.v.) decreases the evoked activity of many classes of spinal cord neurons, both painful and nonnoxious. In SNL and CCI models, the withdrawal threshold was dramatically enhanced by 438079 (100 and 300 μmol/kg, ip) [1]. Sixty minutes after convulsions began, an intraperitoneal dose of A 438079 (5 and 15 mg/kg) decreased intrahippocampal neuronal death and seizure severity. When compared to phenobarbital at the same dose (25 mg/kg), 438079 exhibits better neuroprotective properties [2]. The depletion of striatal DA reserves caused by 6-OHDA is somewhat but significantly prevented by 438079 [3]. In the HC model, a 438079 Pretreatment lowers nociceptive behavior scores [4].
References	[1]. P2X7-related modulation of pathological nociception in rats. Neuroscience. 2007 Jun 8;146(4):1817-28. [2]. CNS Neurosci Ther. 2014 Jun;20(6):556-64. [3]. On the role of P2X(7) receptors in dopamine nerve cell degeneration in a rat model of Parkinson's disease: studies with the P2X(7) receptor antagonist A-438079. J Neural Transm (Vienna). 2010 Jun;117(6):681-7. [4]. The role of P2X7 purinergic receptors in inflammatory and nociceptive changes accompanying cyclophosphamide-induced haemorrhagic cystitis in mice. Br J Pharmacol. 2012 Jan;165(1):183-96.

Solubility Data

Solubility (In Vitro)

DMSO : ~100 mg/mL (~326.64 mM) H2O : ~0.2 mg/mL (~0.65 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.17 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 25.0 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. Solubility in Formulation 2: ≥ 2.5 mg/mL (8.17 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.9188 mL	14.5939 mL	29.1877 mL
	5 mM	0.5838 mL	2.9188 mL	5.8375 mL
	10 mM	0.2919 mL	1.4594 mL	2.9188 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.