Benznidazole (Ro-07-1051; NSC-299972; Radanil) is an FDA approved and orally bioavailable antiparasitic drug used in the treatment of Chagas disease. While it is highly effective in early disease this decreases in those who have long term infection. It is the first line treatment given its moderate side effects compared to nifurtimox. On August 29, 2017, the U.S. Food and Drug Administration granted accelerated approval to benznidazole for use in children ages 2 to 12 years old with Chagas disease. It is the first treatment approved in the United States for the treatment of Chagas disease.

Physicochemical Properties

Molecular Formula	C12H12N4O3
Molecular Weight	260.25
Exact Mass	260.091
Elemental Analysis	C, 55.38; H, 4.65; N, 21.53; O, 18.44
CAS #	22994-85-0
Related CAS #	22994-85-0
PubChem CID	31593
Appearance	Off-white to light yellow solid powder
Density	1.35g/cm3
Melting Point	189-192ºC(lit.)
Index of Refraction	1.643
LogP	2.021
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	4
Heavy Atom Count	19
Complexity	325
Defined Atom Stereocenter Count	0
SMILES	O=C(C([H])([H])N1C([H])=C([H])N=C1[N+](=O)[O-])N([H])C([H])([H])C1C([H])=C([H])C([H])=C([H])C=1[H]
InChi Key	CULUWZNBISUWAS-UHFFFAOYSA-N
InChi Code	InChI=1S/C12H12N4O3/c17-11(14-8-10-4-2-1-3-5-10)9-15-7-6-13-12(15)16(18)19/h1-7H,8-9H2,(H,14,17)
Chemical Name	2-Nitro-N-(phenylmethyl)-1H-imidazole-1-acetamide
Synonyms	Ro 07-1051;NSC299972;Ro 71051;NSC 299972;Ro-07-1051; Ro71051; Benznidazole; NSC-299972; Radanil;
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	Trypanosoma
ln Vivo	When mice infected with Trypanosoma cruzi Tulahuen strain or SGO-Z12 isolate are treated with benzidazole (100 mg/kg/day, p.o., 30 days), the results include a decrease in electrocardiographic alterations, fewer modifications in the affinity and density of cardiac receptors, and a few isolated areas of fibrosis in the heart[1].
Animal Protocol	Animal Model: Mice infected with Trypanosoma cruzi Tulahuen strain or SGO-Z12[1] Dosage: 100 mg/kg/day Administration: Orally for 30 days Result: reduced the number of changes in the affinity and density of cardiac receptors, reduced the number of isolated cardiac fibrosis regions, and decreased electrocardiographic alterations.
ADME/Pharmacokinetics	Absorption, Distribution and Excretion Benznidazole has a bioavailability of 91.7% and a Tmax of 2.93 h. The metabolites of benznidazole appear to be primarily exreted in the urine. The apparent volume of distribution is 39.19 L. The apparent oral clearance is 2.04 L/h. Metabolism / Metabolites Benznidazole is metabolized by nitroreductases in *Trypanosoma cruzi* and by cytochrome P450 enzymes. Biological Half-Life The half life of elimination is 13.27 h.
Toxicity/Toxicokinetics	Hepatotoxicity Benznidazole therapy is associated with an appreciable rate of serum enzyme elevations, found in at least 10% of patients. The abnormalities, however, are generally mild, transient and without accompanying symptoms or jaundice. In clinical trials there were no reported instances of clinically apparent liver injury with jaundice attributed to benznidazole. However, since its approval and more widescale use, there have been several case reports of drug rash with eosinophilia and systemic symptoms (DRESS syndrome) accompanied by serum enzyme elevations associated with benznidazole therapy, one of which was accompanied by jaundice. Furthermore, cases of immunoallergic hepatitis have been reported with other more commonly used nitroimidazoles such as metronidazole and ornidazole, some of which have been severe. Thus, benznidazole therapy has had limited clinical use, but it appears to have the potential to cause symptomatic, immunoallergic hepatitis with jaundice. Likelihood score: D (possible rare cause of clinically apparent liver injury, usually as a component of DRESS syndrome). Effects During Pregnancy and Lactation ◉ Summary of Use during Lactation Benznidazole is excreted into milk in dosages much lower than the treatment dosage for infants. Because of the low levels of benznidazole in breastmilk and safety when given directly to infants, its use is acceptable in nursing mothers. ◉ Effects in Breastfed Infants Ten women with chronic Chagas disease received benznidazole in a median oral dose of 5.65 mg/kg twice daily for 30 days. Median infant age Ten women with chronic Chagas disease received benznidazole in a median oral dose of 5.65 mg/kg twice daily for 30 days. Median infant age was 5.2 months (range 20 days-13 months). Five children were exclusively breastfed and the others partially breastfed. None of the infants had any adverse reactions attributable to benznidazole. A postpartum woman diagnosed with Chagas disease was treated with benznidazole 5 mg/kg daily beginning one month postpartum and continuing for 30 days. She continued to breastfeed (extent not stated) her infant. The authors reported that no adverse effects were seen in the infant. ◉ Effects on Lactation and Breastmilk Relevant published information was not found as of the revision date.
References	[1]. Int J Antimicrob Agents. 2007 Jun;29(6):733-7. [2]. Biomedica. 2009 Sep;29(3):448-55. [3]. PLoS Negl Trop Dis.2018 Nov 1;12(11):e0006814.
Additional Infomation	Benznidazole is a monocarboxylic acid amide obtained by formal condensation of the carboxy group of (2-nitroimidazol-1-yl)acetic acid with the aromatic amino group of benzylamine. Used for treatment of Chagas disease. It has a role as an antiprotozoal drug. It is a member of imidazoles, a C-nitro compound and a monocarboxylic acid amide. Benznidazole is an antiprotozoal prescription medicine approved by the Food and Drug Administration (FDA) for the treatment of Chagas disease caused by infection with the parasite Trypanosoma cruzi. Benznidazole is FDA-approved for use in children 2 to 12 years of age. Chagas disease can be opportunistic infections (OI) of HIV. Benznidazole was granted accelerated approval for the treatment of Chagas disease in children 2-12 years of age by the FDA on August 29, 2017. It is the first treatment made available in the United States for Chagas disease. Benznidazole is an orally available, broad spectrum antimicrobial agent used in the treatment of Chagas disease (American trypanosomiasis). Benznidazole is a nitroimidazole similar to metronidazole and is associated with serum enzyme elevations during therapy in up to 10% of patients but has not linked to cases of clinically apparent acute liver injury. Benznidazole has been reported in Xenorhabdus nematophila with data available. Benznidazole is a nitroimidazole derivative having an antiprotozoal activity by interfering with parasite protein biosynthesis, influencing cytokines production and stimulating host phagocytosis. (NCI) Drug Indication For use in the treatment of Chagas disease in children 2-12 years of age. Mechanism of Action Benznidazole is thought to be reduced to various electrophilic metabolites by nitroreductases present in *Trypanosoma cruzi*. These metabolites likely bind to proteins, lipids, DNA, and RNA resulting in damage to these macromolecules. Benznidazole has been found to increase trypanosomal death through interferon-γ which is likely present in increased amounts due to inflammation caused by macromolecule damage. DNA in parasites affected by benznidazole has been found to undergo extensive unpacking with overexpression of DNA repair proteins supporting the idea of DNA damage contributing to the mechanism of the drug. Pharmacodynamics Benznidazole is a trypanocidal agent which kills the causative organism in Chagas disease, *Trypanosoma cruzi*.

Solubility Data

Solubility (In Vitro)

DMSO : 50~52 mg/mL ( 192.12~199.8 mM ) Ethanol : ~5 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.99 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 (7.99 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. Solubility in Formulation 3: ≥ 2.08 mg/mL (7.99 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.08 mg/mL (7.99 mM)  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.8425 mL	19.2123 mL	38.4246 mL
	5 mM	0.7685 mL	3.8425 mL	7.6849 mL
	10 mM	0.3842 mL	1.9212 mL	3.8425 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.