Triazavirin sodium hydrate (TZV, Riamilovir), a nucleoside analogue of nucleic acid, is a broad-spectrum and potent antiviral agent. Its anti-influenza activity has been the main focus of testing since it was first created as a possible treatment for pandemic influenza strains like H5N1. Triazavirin, however, has also been shown to exhibit antiviral activity against several other viruses, such as the Forest-Spring Encephalitis and Tick-borne encephalitis viruses[6]. It is also being researched for possible use against Lassa fever and Ebola virus disease. Triazavirin began to be tested against SARS-CoV-2 in February 2020. Triazavirin functions by preventing genomic fragment replication and the synthesis of viral RNA and DNA. Triazavirin is likewise a useful preventive medication during the influenza transmission stage.

Physicochemical Properties

Molecular Formula	C₅H₇N₆NAO₅S
Molecular Weight	286.20
Exact Mass	286.009
Elemental Analysis	C, 20.98; H, 2.47; N, 29.37; Na, 8.03; O, 27.95; S, 11.20
CAS #	928659-17-0
Related CAS #	116061-59-7 (sodium);123606-06-4 (free);928659-17-0 (sodium hydrate);
PubChem CID	52947239
Appearance	Light yellow to yellow solid powder
LogP	2.0
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	10
Rotatable Bond Count	1
Heavy Atom Count	18
Complexity	262
Defined Atom Stereocenter Count	0
SMILES	[Na].O=C1N2C(NC(SC)=N2)=NN=C1[N+](=O)[O-].O
InChi Key	GDVSBVWTWGUDAW-UHFFFAOYSA-M
InChi Code	InChI=1S/C5H4N6O3S.Na.2H2O/c1-15-5-6-4-8-7-2(11(13)14)3(12)10(4)9-5;;;/h12H,1H3;;2*1H2/q;+1;;/p-1
Chemical Name	sodium;7-methylsulfanyl-3-nitro-[1,2,4]triazolo[5,1-c][1,2,4]triazin-4-olate;dihydrate
Synonyms	Triazavirin; Riamilovir; TZV; Riamilovir sodium hydrate
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	Nucleoside analogue; Influenza virus
ln Vitro	Triazavirin's effectiveness against the tick-borne encephalitis virus is measured in a sensitive cell culture. Triazavirin is effective in inhibiting the reproduction of the tick-borne encephalitis virus (strain Sofiin) by accumulation in the SKEV cell culture at a concentration of 128 mcg/mL[2].
ln Vivo	Triazavirin's effectiveness as a treatment against experimental Forest-Spring encephalitis in albino mice is investigated. The findings indicate that triazavirin, at high doses (200–400 mg/kg), protects the infected animals in a moderate way. Test groups' animal lifespans increased significantly (from 4.1 to 4.8 days) and there was a statistically significant drop in the amount of virus accumulation in the target organ[3].
Cell Assay	The efficacy of Triazavirin against the tick-borne encephalitis virus was estimated in the sensitive cell culture vs. the active drug Ribavirin. In a concentration of 128 mcg/ml Triazavirin was shown active in inhibition of the tick-borne encephalitis virus reproduction (strain Sofiin) by accumulation in the SKEV cell culture[2].
Animal Protocol	The comparative study of the therapeutic efficacy of Triazavirin against experimental Forest-Spring encephalitis on albino mice vs. the active drug Ribavirin® showed that in high doses (200-400 mg/kg) Triazavirin moderately protected the infected animals. A significant increase of the animal lifespan in the test groups (from 4.1 to 4.8 days) and a statistically (p ≤ 0.05) valid decrease of the virus accumulation in the target organ (the brain) were observed[3].
References	[1]. Kozhikhova KV, et al. Preparation of chitosan-coated liposomes as a novel carrier system for the antiviral drug Triazavirin. Pharm Dev Technol. 2018 Apr;23(4):334-342. [2]. Loginova SIa, et al. Investigation of Triazavirin antiviral activity against tick-borne encephalitis pathogen in cell culture. Antibiot Khimioter. 2014;59(1-2):3-5. [3]. Loginova SY, et al. Investigation of Therapeutic Efficacy of Triazavirin Against Experimental Forest-Spring Encephalitis on Albino Mice. Antibiot Khimioter. 2015;60(7-8):11-3.
Additional Infomation	See also: Riamilovir (annotation moved to).

Solubility Data

Solubility (In Vitro)

DMSO: ~125 mg/mL (~436.8 mM) H2O: ~50 mg/mL (~174.7 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.27 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 20.8 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: ≥ 2.08 mg/mL (7.27 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 20.8 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	3.4941 mL	17.4703 mL	34.9406 mL
	5 mM	0.6988 mL	3.4941 mL	6.9881 mL
	10 mM	0.3494 mL	1.7470 mL	3.4941 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.