Nitrogen

Synonyms: Azote; E941; nitrogenium.

Description: Nitrogen occurs naturally as approximately 78% v/v of the atmosphere. It is a nonreactive, noncombustible, colorless, tasteless, and odorless gas. It is usually handled as a compressed gas, stored in metal cylinders.

Chemical Name: Nitrogen

Aerosol propellant; air displacement.

• Nitrogen and other compressed gases such as carbon dioxide and nitrous oxide are used as propellants for topical pharmaceutical aerosols.

• They are also used in other aerosol products that work satisfactorily with the coarse aerosol spray produced with compressed gases, e.g. furniture polish and window cleaner.

• Nitrogen is insoluble in water and other solvents, and therefore remains separated from the actual pharmaceutical formulation.

• Advantages of compressed gases as aerosol propellants are that they are less expensive; of low toxicity; and practically odorless and tasteless.

• In contrast to liquefied gases, their pressures change relatively little with temperature.

• However, there is no reservoir of propellant in the aerosol and as a result the pressure decreases as the product is used, changing the spray characteristics.

• Misuse of a product by the consumer, such as using a product inverted, results in the discharge of the vapor phase instead of the liquid phase.

• Most of the propellant is contained in the vapor phase and therefore some of the propellant will be lost and the spray N Nitrogen 461 characteristics will be altered.

• Additionally, the sprays produced using compressed gases are very wet. However, recent developments in valve technology have reduced the risk of misuse by making available valves which will spray only the product (not propellant) regardless of the position of the container. Additionally, barrier systems will also prevent loss of propellant, and have been used for pharmaceuticals and cosmetic aerosol sprays and foams utilizing nitrogen as the propellant.

• Nitrogen is also used to displace air from solutions subject to oxidation, by sparging, and to replace air in the headspace above products in their final packaging, e.g. in parenteral products packaged in glass ampoules. Nitrogen is also used for the same purpose in many food products.

Generally compatible with most materials encountered in pharmaceutical formulations and food products.

Nitrogen is generally regarded as a nontoxic and nonirritant material. However, it is an asphyxiant and inhalation of large quantities is therefore hazardous

Handle in accordance with procedures for handling metal cylinders containing liquefied or compressed gases. Eye protection, gloves, and protective clothing are recommended. Nitrogen is an asphyxiant and should be handled in a well-ventilated environment.

Carbon dioxide; nitrous oxide.