Sodium nitrite is a chemical compound, sodium ion with inorganic sodium salt and a physiological derivative of nitric oxide to which it can be bioactivated.  It is very soluble in water and liquid ammonia, stable under anaerobic conditions. Slightly soluble in ether, ethanol, methanol and other organic solvents. It reacts with oxygen to form sodium nitrate when exposed to air.

It occurs as a white or yellowish crystalline powder.

What it is used for and where it is used

It is used in medicine, food, fertiliser, fixative in dyes, biological insecticide, antifreeze, raw material in the production of caffeine and saccharin, corrosion inhibitor for steel, bleaching agent for silk and linen, heat treatment agent for metals, bleaching, electroplating.

Chromatography: to determine mercury, potassium and chlorate. Nitrification and diazotization reagent (temporary generation of sodium nitrite and hydrochloric acid). Soil analysis.  Serum bilirubin measured in liver function tests.

Medicine

Sodium nitrite is an analytical reagent, a vasodilator that generates nitric oxide in tissues by involving haemoglobin, an antidote to cyanide poisoning.

It also has antimicrobial activity by inhibiting enzymes or disrupting electron transport in various microbes (1), can improve cardiac function and, as an effective cardioprotective treatment, is also cost-effective.

This study investigated the protective response in the presence of ischaemia or hypoxic conditions and concluded that exogenous sodium nitrite had protective effects against hepatic ischaemia-reperfusion injury (2).

Sickle cell skin ulceration has a negative impact on quality of life. Topical sodium nitrite has been shown to reduce the size of sickle cell leg ulcers. This study examined how topical sodium nitrite affected quality of life scores in patients with sickle cell leg ulcers. Topical sodium nitrite has the potential to improve quality of life, especially in younger people. Longer duration of treatment and randomised trials are needed to confirm the efficacy of this topical therapy (3).

Sodium nitrite can be considered an effective therapeutic agent for diseases of the central nervous system (4).

Sodium nitrite (Medicine) studies

Its use in food is permitted but at concentrations strictly established by European food additive legislation (Regulation (EC) No 1333/2008). It is labelled with the number E250 on the European additives list as a preservative and is subject to an Acceptable Daily Intake (ADI). 

Typical optimal characteristics of the commercial product Sodium nitrite

Appearance	Colorless or yellow crystal
Content of sodium nitrite %	≥98.5
Boiling Point	320 °C
Melting Point	271 °C(lit.)
Density	1.29 g/mL at 25 °C
PSA	52.49000
LogP	0.25060
Water Solubility	820 g/L (20 ºC)
Water insoluble matter	≤0.05%
Sodium nitrate	≤0.8%
Chloride	≤50ppm
Moisture %	≤2.0
Storage	2-8°C
Safety

• Molecular Formula : NNaO₂
• Molecular Weight : 68.995
• Exact Mass   68.982674
• CAS : 7632-00-0
• UNII M0KG633D4F
• EC Number   231-555-9
• DSSTox Substance ID DTXSID0020941
• IUPAC  sodium;nitrite
• InChI=1S/HNO2.Na/c2-1-3;/h(H,2,3);/q;+1/p-1  
• InChl Key      LPXPTNMVRIOKMN-UHFFFAOYSA-M
• SMILES   N(=O)[O-].[Na+]
• MDL number  MFCD00011118
• PubChem Substance ID 329752451
• ChEBI  78870
• ICSC    1120
• NSC   77391
• RTECS   RA1225000
• UN   1500   3287

Synonyms :

• Nitrous acid, sodium salt
• Nitrite, Sodium

References________________________________________________

(1) Mueller-Herbst S, Muehlig A, Kabisch J, Pichner R, Scherer S. The food additives nitrite and nitrate and microbiological safety of food products. American Journal of Clinical Microbiology. 2014;6(1):13. doi: 10.3844/ajmsp.2015.1.3.

(2) Choi EK, Jung H, Kim KJ, Kang SJ, Kim HJ, Lim JA, Kwak KH, Lim DG. Sodium Nitrite Attenuates Hepatic Ischemia-Reperfusion Injury in Rats. Exp Clin Transplant. 2019 Jun;17(3):348-354. doi: 10.6002/ect.2018.0169.

(3) Connor JL Jr, Sclafani JA, Kato GJ, Hsieh MM, Minniti CP. Brief topical sodium nitrite and its impact on the quality of life in patients with sickle leg ulcers. Medicine (Baltimore). 2018 Nov;97(46):e12614. doi: 10.1097/MD.0000000000012614.

(4) Pluta RM, Oldfield EH. Sodium nitrite as a therapeutic agent for central nervous system diseases. Surg Neurol. 2006 Jul;66(1):5-7; discussion 8-10. doi: 10.1016/j.surneu.2005.10.017.