Tizoxanide, a thiazolide anti-infective, is an active metabolite of Nitazoxanide (also known as NTZ; NSC 697855), which is a synthetic nitrothiazolyl-salicylamide derivative and an antiprotozoal agent with IC50 for canine influenza virus ranges from 0.17 to 0.21 μM. Tizoxanide is active against anaerobic bacteria, protozoa, and a range of viruses in cell culture models, and is currently in phase II clinical development for treating chronic hepatitis C.

Physicochemical Properties

Molecular Formula	C10H7N3O4S
Molecular Weight	265.25
Exact Mass	265.015
Elemental Analysis	C, 45.28; H, 2.66; N, 15.84; O, 24.13; S, 12.09
CAS #	173903-47-4
Related CAS #	Tizoxanide-d4;1246817-56-0
PubChem CID	394397
Appearance	Solid powder
Density	1.6±0.1 g/cm3
Melting Point	279-281ºC(dec)
Index of Refraction	1.750
LogP	2.91
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	2
Heavy Atom Count	18
Complexity	336
Defined Atom Stereocenter Count	0
SMILES	S1C(=C([H])N=C1N([H])C(C1=C([H])C([H])=C([H])C([H])=C1O[H])=O)[N+](=O)[O-]
InChi Key	FDTZUTSGGSRHQF-UHFFFAOYSA-N
InChi Code	InChI=1S/C10H7N3O4S/c14-7-4-2-1-3-6(7)9(15)12-10-11-5-8(18-10)13(16)17/h1-5,14H,(H,11,12,15)
Chemical Name	2-hydroxy-N-(5-nitrothiazol-2-yl)benzamide
Synonyms	NSC-697856; NSC697856; Tizoxanide; 173903-47-4; 2-hydroxy-N-(5-nitrothiazol-2-yl)benzamide; Benzamide, 2-hydroxy-N-(5-nitro-2-thiazolyl)-; Desacetyl-nitazoxanide; NSC-697856; 2-hydroxy-N-(5-nitro-1,3-thiazol-2-yl)benzamide; UNII-15KFG88UOJ; NSC697856; Tizoxanide; Desacetylnitazoxanide; Desacetyl-nitazoxanide;
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	HIV-1; HBV/HCV (EC50 = 0.46μM and 0.15 μM)
ln Vitro	Tizoxanide is the active metabolite of Nitazoxanide, which is a thiazolide anti-infective compound against anaerobic bacteria, protozoa, and a range of viruses. IC50 value: Target: Antiviral agent in vitro: Tizoxanide inhibited virus replication of all CIVs with 50% and 90% inhibitory concentrations ranging from 0.17 to 0.21 μM and from 0.60 to 0.76 μM, respectively. Nitazoxanide and its primary metabolite, tizoxanide, inhibit hepatitis C virus (HCV) replication in HCV replicon systems. Interestingly, serial passage in nitazoxanide or tizoxanide resulted in increased sensitivity to alpha interferon 2b: EC(50)s and EC(90)s were reduced three- and eightfold, respectively.
ln Vivo	Nitazoxanide is partially effective at reducing the parasite burden in a gnotobiotic piglet diarrhea model when given orally for 11 days at 250 mg/kg/day but not at 125 mg/kg/day. Nitazoxanide induces a drug-related diarrhea in piglets that might have influenced its therapeutic efficacy.
Animal Protocol
ADME/Pharmacokinetics	Metabolism / Metabolites Tizoxanide has known human metabolites that include (2S,3S,4S,5R)-3,4,5-Trihydroxy-6-[2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenoxy]oxane-2-carboxylic acid.
References	[1]. Antimicrob Agents Chemother.1998 Aug;42(8):1959-65. [2]. Clin Infect Dis.2005 Apr 15;40(8):1173-80.
Additional Infomation	Desacetyl-nitazoxanide is a member of salicylamides. Nitazoxanide (NTZ), a drug currently being tested in human clinical trials for efficacy against chronic cryptosporidiosis, was assessed in cell culture and in two animal models. The inhibitory activity of NTZ was compared with that of paromomycin (PRM), a drug that is partially effective against Cryptosporidium parvum. A concentration of 10 microg of NTZ/ml (32 microM) consistently reduced parasite growth in cell culture by more than 90% with little evidence of drug-associated cytotoxicity, in contrast to an 80% reduction produced by PRM at 2,000 microg/ml (3.2 mM). In contrast to its efficacy in vitro, NTZ at either 100 or 200 mg/kg of body weight/day for 10 days was ineffective at reducing the parasite burden in C. parvum-infected, anti-gamma-interferon-conditioned SCID mice. Combined treatment with NTZ and PRM was no more effective than treatment with PRM alone. Finally, NTZ was partially effective at reducing the parasite burden in a gnotobiotic piglet diarrhea model when given orally for 11 days at 250 mg/kg/day but not at 125 mg/kg/day. However, the higher dose of NTZ induced a drug-related diarrhea in piglets that might have influenced its therapeutic efficacy. As we have previously reported, PRM was effective at markedly reducing the parasite burden in piglets at a dosage of 500 mg/kg/day. Our results indicate that of all of the models tested, the piglet diarrhea model most closely mimics the partial response to NTZ treatment reported to occur in patients with chronic cryptosporidiosis. [1] Nitazoxanide is a new thiazolide antiparasitic agent that shows excellent in vitro activity against a wide variety of protozoa and helminths. It is given by the oral route with good bioavailability and is well tolerated, with primarily mild gastrointestinal side effects. At present, there are no documented drug-drug interactions. Nitazoxanide has been licensed for the treatment of Giardia intestinalis-induced diarrhea in patients >or=1 year of age and Cryptosporidum-induced diarrhea in children aged 1-11 years. At present, it is pending licensure for treatment of infection due to Cryptosporidium species in adults and for use in treating immunocompromised hosts. It represents an important addition to the antiparasitic arsenal. [2]

Solubility Data

Solubility (In Vitro)

DMSO : ~25 mg/mL (~94.25 mM) Ethanol : < 1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: 5 mg/mL (18.85 mM) in 15% Cremophor EL + 85% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication (<60°C). Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: 15% Cremophor EL+85% Saline: 5 mg/mL (18.85 mM) Solubility in Formulation 3: 5 mg/mL (18.85 mM) in 17% Polyethylene glycol 12-hydroxystearate in Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication (<60°C). Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O 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	3.7700 mL	18.8501 mL	37.7003 mL
	5 mM	0.7540 mL	3.7700 mL	7.5401 mL
	10 mM	0.3770 mL	1.8850 mL	3.7700 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.