MEG (Mercaptoethylguanidine) hemisulfate is a potent and specific inhibitor of inducible NO synthase (iNOS). It inhibits iNOS in tissue homogenates with EC50s of 11.5, 110 and 60 μM for ecNOS and bNOS, respectively. MEG hemisulfate is also an effective peroxynitrite scavenger and inhibits peroxynitrite-induced oxidation processes. MEG hemisulfate has protective effects in many experimental models of inflammation such as ischemia/reperfusion injury, periodontitis, hemorrhagic shock, inflammatory bowel disease, and endotoxin and septic shock.

Physicochemical Properties

Molecular Formula	C6H20N6O4S3
Molecular Weight	336.45600
Exact Mass	336.07
CAS #	3979-00-8
PubChem CID	16219710
Appearance	Typically exists as solid at room temperature
Boiling Point	645.7ºC at 760 mmHg
Flash Point	344.3ºC
LogP	1.608
Hydrogen Bond Donor Count	8
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	4
Heavy Atom Count	19
Complexity	148
Defined Atom Stereocenter Count	0
SMILES	C(CS)NC(=N)N.C(CS)NC(=N)N.OS(=O)(=O)O
InChi Key	XJKZAAUVINNNNC-UHFFFAOYSA-N
InChi Code	InChI=1S/2C3H9N3S.H2O4S/c2*4-3(5)6-1-2-7;1-5(2,3)4/h2*7H,1-2H2,(H4,4,5,6);(H2,1,2,3,4)
Chemical Name	2-(2-sulfanylethyl)guanidine;sulfuric acid
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

Targets	IC50: 11.5 μM (iNOS), 110 μM (ecNOS), 60 μM (bNOS)[1]
ln Vitro	In the supernatant of cultured J774.2 macrophages stimulated with LPS (10 μg/mL) and INF (50 μg/mL), MEG (0.1-1000 μM; 18 h) decreases nitrite buildup. In lung homogenates from rats given LPS, MEG suppresses iNOS activity[1]. MEG (1 μM-3 mM; 3 min) suppresses the hydroxylation of benzoate and the oxidation of cytochrome c2+ caused by peroxynitrite in a dose-dependent manner[2]. MEG (1–300 μM) prevents J774 cells from suppressing mitochondrial respiration and breaking DNA strands individually in response to peroxynitrite[2]. In thoracic aortic rings, MEG (300 μM; 30 min) prevents the inhibition of vascular contractility in response to peroxynitrite[2].
ln Vivo	In rats with caustic burn injuries to their esophagus, MEG (10 mg/kg; intraperitoneally for 5 days) reduces the amount of lipid peroxidation, protein oxidation, and peroxynitrites while also improving the decline in antioxidant enzyme activity[3]. MEG (30–60 mg/kg; one intraperitoneal) lowers normal rats' mean arterial blood pressure (MAP)[1]. MEG (10 mg/kg; one intraperitoneal; i.p.) ameliorates tissue damage and renal dysfunction brought on by ischemia/reperfusion (I/R) in the rat kidney[4].
Animal Protocol	Animal/Disease Models: SD (Sprague-Dawley) rats (200-250 g) were injured the esophagus[3] Doses: 10 mg/kg Route of Administration: Ip for 5 days Experimental Results: decreased the stenosis index (SI ) and the histopathologic damage score. diminished the malondialdehyde and protein carbonyl content and increased the activities of superoxide dismutase and glutathione peroxidase. Regulated the nitrate and nitrite level.
References	[1]. Spontaneous rearrangement of aminoalkylisothioureas into mercaptoalkylguanidines, a novel class of nitric oxide synthase inhibitors with selectivity towards the inducible isoform. Br J Pharmacol. 1996 Feb;117(4):619-32. [2]. Mercaptoethylguanidine and guanidine inhibitors of nitric-oxide synthase react with peroxynitrite and protect against peroxynitrite-induced oxidative damage. J Biol Chem. 1997 Apr 4;272(14):9030-6. [3]. Mercaptoethylguanidine attenuates caustic esophageal injury in rats: a role for scavenging of peroxynitrite. J Pediatr Surg. 2011 Sep;46(9):1746-52. [4]. Scavenging of peroxynitrite reduces renal ischemia/reperfusion injury. Ren Fail. 2008;30(7):747-54.

Solubility Data

Solubility (In Vitro)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *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. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.9721 mL	14.8606 mL	29.7212 mL
	5 mM	0.5944 mL	2.9721 mL	5.9442 mL
	10 mM	0.2972 mL	1.4861 mL	2.9721 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.