The Concept of Pharmaceutical Water

The appendix of the Chinese Pharmacopoeia (2000 edition) includes the concept of pharmaceutical water, classifying it into three types according to its scope of use: purified water, water for injection, and sterile water for injection, replacing distilled water with purified water [1]. USP24 includes seven types of pharmaceutical water, four more than the Chinese Pharmacopoeia (2000 edition): sterile purified water, bacteriostatic water for injection, sterile perfusion water, and sterile inhalation water. These are described below:

Purified Water

Unlike previous editions of the Pharmacopoeia, the 2000 edition of the Chinese Pharmacopoeia does not specify the specific production process for purified water, but it has made significant improvements in water quality standards and testing methods.

Water for Injection

Water for injection uses drinking water or purified water as raw material and is produced by distillation or reverse osmosis. The final treatment steps for both distillation and reverse osmosis methods were established starting with USP19 in 1975.

Sterile Purified Water

Sterile purified water is packaged and sterilized purified water, primarily used for large-volume sterilized preparations other than enteric drugs.

Sterile Water for Injection

Sterile water for injection is packaged and sterilized water for injection, packaged in single-dose containers not exceeding 1L.

Bacteriostatic Water for Injection

Bacteriostatic water for injection is water for injection containing a bacteriostatic agent, used as a diluent for enteric drug preparations. It can be packaged in single-dose or multi-dose containers, with a packaging volume not exceeding 30ml. Its compatibility with injectable drug preparations should be considered during use, and it should not be used on newborns.

Sterile Water for Perfusion

Sterile water for perfusion is sterilized, single-dose packaged water for injection, intended for perfusion, with a packaging volume greater than 1L.

Sterile Water for Inhalation

Sterile water for inhalation is sterilized, appropriately packaged water for injection, used for inhalation therapy.