Water

Synonyms: Aqua; aqua purificata; hydrogen oxide.

Description: The term ‘water’ is used to describe potable water that is freshly drawn direct from the public supply and is suitable for drinking. Water used in the pharmaceutical industry and related disciplines is classified as either drinking (potable) water, purified water, sterile purified water, water for injection (WFI), sterile water for injection, bacteriostatic water for injection, sterile water for irrigation, or sterile water for inhalation. Validation is required for all systems producing the water indicated, with the exception of potable water. The chemical composition of potable water is variable, and the nature and concentrations of the impurities in it depend upon the source from which it is drawn. Water classified as potable water for applications such as some initial rinsing and API manufacturing operations, must meet the US Environmental Protection Agency’s National Primary Drinking Water Regulations, or comparable regulations of the EU or Japan. For most pharmaceutical applications, potable water is purified by distillation, ion exchange treatment, reverse osmosis (RO), or some other suitable process to produce ‘purified water’. For certain applications, water with pharmacopeial specifications differing from those of purified water should be used, e.g. WFI. Water is a clear, colorless, odorless, and tasteless liquid.

Chemical Name: Water

Solvent

• Water is widely used as a raw material, ingredient and solvent in the processing, formulation and manufacture of pharmaceutical products, active pharmaceutical ingredients (API) and intermediates, and analytical reagents. Specific grades of water are used for particular applications in concentrations up to 100%

In pharmaceutical formulations, water can react with drugs and other excipients that are susceptible to hydrolysis (decomposition in the presence of water or moisture) at ambient and elevated temperatures. Water can react violently with alkali metals and rapidly with alkaline metals and their oxides, such as calcium oxide and magnesium oxide. Water also reacts with anhydrous salts to form hydrates of various compositions, and with certain organic materials and calcium carbide.

Water is the base for many biological life forms, and its safety in pharmaceutical formulations is unquestioned provided it meets standards of quality for potability and microbial content. Plain water is considered slightly more toxic upon injection into laboratory animals than physiological salt solutions such as normal saline or Ringer’s solution. Ingestion of excessive quantities of water can lead to water intoxication, with disturbances of the electrolyte balance. WFI should be free from pyrogens.

Observe normal precautions appropriate to the circumstances and quantity of material handled.

Bacteriostatic water for injection; carbon dioxide-free water; deaerated water; hard water; soft water; sterile water for inhalation; sterile water for injection; sterile water for irrigation; water for injection (WFI)