Sodium nitrite is an inorganic compound that is used as a preservative in cured meats. It acts as an antioxidant and prevents the growth of Clostridium botulinum and Listeria monocytogenes in meats. Sodium nitrite can also be used to treat cyanide poisoning by converting to nitric oxide in the body. It has potential medical uses in treating high blood pressure and organ damage by dilating blood vessels. Industrially, sodium nitrite is used in dye production, rubber industry, photography, electrochemical grinding, and metallurgy. It comes in various dosage forms including injections and inhalants for treating cyanide poisoning.

1. Mahpara Gondal
Rashid Latif College of Pharmacy

2. Sodium Nitrite
 Sodium nitrite is an
inorganic compound.
Noncombustible but will
accelerate the burning of
combustible material. If
large quantities are involved
in a fire or if the combustible
material is finely divided, an
explosion may result.
 Act as anti-oxidant that is
used to cure meats

3. Occurance
 Less than five percent of daily nitrite intake
comes from cured meats. Nearly 93 percent of
nitrite comes from leafy vegetables & tubers and
our own saliva. Vegetables contain sodium nitrate,
which is converted to nitrite when it comes into
contact with saliva in the mouth.
 There is another source of nitrite in the body, nitric
oxide is an amazing chemical that the body uses
to control blood pressure, kill tumor cells and heal
wounds. When nitrite oxide is done with its work,
its by product is nitrite. So clearly, nitrite is
something that is made by the body as part of its
normal, healthy processes.

4. Physical properties
Formula: NaNO2
Mol Wt : 69 g/mol
PHYSICAL PROPERTIES
It is a white to slightly yellowish crystalline powder that is
very soluble in water and is hygroscopic
Odor: specific odor
Density: 2.168g/cm3
Solubility: freely soluble in water and soluble in alcohol.
Melting Point: 271 °C
PH: Between 7 and 9.

5. Chemical Properties
 1. In the laboratory, sodium nitrite can be used to destroy
excess sodium azide.
2 NaN3 + 2 NaNO2 + 2 H+ → 3 N2 + 2 NO + 2 Na+ + 2 H2O
 2. Above 330 °C sodium nitrite decomposes (in air) to
sodium oxide, nitric oxide and nitrogen dioxide.
2 NaNO2 → Na2O + NO + NO2
 3. Sodium nitrite can also be used in the production of
nitrous acid via sulfuric acid. This reaction first yields
nitrous acid and sodium sulfate:
2 NaNO2 + H2SO4 → 2 HNO2 + Na2SO4

6. Cont…
 The nitrous acid then, under normal conditions,
decomposes:
2 HNO2 → NO2 + NO + H2O
 The nitrogen dioxide of the prior decomposition is
then routed through a condensor or fractional
distillation apparatus to react with water and yield
nitric acid:
2 NO2 + H2O → HNO3 + HNO2

7. Preparation
 1. The salt is prepared by treating sodium hydroxide
with mixtures of nitrogen dioxide and nitric oxide:
NaOH + NO2 + NO → 2 NaNO2 + H2O
The conversion is sensitive to the presence of oxygen,
which can lead to varying amounts of sodium nitrate.
 Note
In former times, sodium nitrite was prepared by
reduction of sodium nitrate with various metals.

8. Cont…
 2. Sodium nitrite can be prepare from sodium carbonate.
 Caustic soda or soda ash solution absorbing tail gas containing a small amount of
NO and NO2 use in nitric acid or a nitrate production. In the tail gas of NO/NO2
ratio should be adjust according to NaNO2 and NaNO3 production.
 The prior art, for absorbing nitrogen oxides to obtain a nitrite, the theoretical
composition of the nitrogen oxides for nitrite formation is equal proportions of NO
and NO2. It is usual, however, in these processes an excess of nitric oxide (NO)
over nitrogen dioxide (NO2) in order to promote the formation of nitrite and
minimize the amount of nitrate formed. The content of soda ash is 3 ~ 5 g/L and
send to evaporation, absorb liquid evaporation concentration at 132 ℃, then cool to
75 ℃, precipitation sodium nitrite in crystallization, then through separation, drying
to quick product.
Na2CO3 + NO + NO2→2 NaNO2 + CO2

9. Uses
 Sodium Nitrite is used as part of an intravenous mixture with
sodium thiosulfate to treat cyanide poisoning. The compound is
toxic and mutagenic and will react in vivo with secondary or
tertiary amines thereby producing highly carcinogenic
nitrosamines.
 Indeed, according to Healthsafety.org sodium nitrite works
with sodium chloride, or salt, to inhibit the growth of
Clostridium botulinum. Clostridium botulinum is an organism
that can cause fatal food poisoning.

10. Cont..
 sodium nitrite is also effective against Listeria monocytogenes, another
disease-causing organism. According to the National Institutes of Health,
sodium nitrite also shows promise in the treatment of high blood pressure,
kidney failure, heart disease and organ damage.
 In oxygen-poor tissues, nitrite can convert into nitric oxide (NO), state the
National Institutes of Health. Nitric oxide is a chemical that dilates your
blood vessels to enhance blood flow.. Nitrate, on the other hand, cannot
convert into nitric oxide in your blood. Even though sodium nitrate can
theoretically convert into sodium nitrite, NIH study findings indicate that
only low concentrations of nitrite protect the body against tissue injury.

11. Non Pharma-Uses
 The main use of sodium nitrite is for the industrial production of
organonitrogen compounds. It is a reagent for conversion of amines
into diazo compounds, which are key precursors to many dyes, such
as diazo dyes.
 Nitroso compounds are produced from nitrites. These are used in the
rubber industry.
 Other applications include uses in photography. It may also be used
as an electrolyte in electrochemical grinding manufacturing
processes, typically diluted to about 10% concentration in water. It is
used in a variety of metallurgical applications, for phosphatizing and
detinning.
 Sodium nitrite is an effective corrosion inhibitor and is used as an
additive in industrial greases, as an aqueous solution in closed loop
cooling systems, and in a molten state as a heat transfer medium.

12. Dosage forms
 Brand and Other Names: Nithiodote
 Classes: Cyanide Antidotes
 Dosing Form & Strengths
 kit
 sodium thiosulfate injection: 250mg/mL 1 vial
 sodium nitrite injection: 30mg/mL 1 vial

13. Cont…
 Brand and Other Names: cyanide antidote kit
 Classes: Cyanide Antidotes
per kit
 sodium thiosulfate injection: 12.5g/50mL (2 vials)
 sodium nitrite: 300mg/10mL (2 ampules)
 amyl nitrite inhalant: 0.3mL (12 ampules)
 Mechanism of action/Effect:
Antidote (to cyanide poisoning)—Sodium nitrite promotes formation of
methemoglobin, which combines with cyanide to form nontoxic
cyanmethemoglobin.
 Other actions/effects:
Sodium nitrite produces vasodilation by relaxing vascular smooth muscle