Pharmaceutical water: Purified water, WFI, SWFI, BWFI, & BET

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In the Pharmaceutical industry, Water is widely used as raw material, ingredient, and solvent in the processing, formulation, and manufacture of pharmaceutical products, active pharmaceutical ingredients (APIs) and intermediates, compendial articles, and analytical reagents.

There are many different grades of water used for pharmaceutical purposes. Several are described in various Pharmacopoeia‘s (IP, USP, BP etc) monographs that specify uses, acceptable methods of preparation, and quality attributes. Different grades of water quality are required depending on the different pharmaceutical uses.

Type of Water for Pharmaceutical use

Type of Water	Description (As per Indian Pharmacopoeia)
Purified water CFU – 100	-Prepared by distillation reverse osmosis & same time Ion-exchange. -Used as a solvent in all pharmaceutical preparation except parenteral sterile preparation. -Also used for all tests & assays of the IP, unless otherwise specified -Hand washing (In the sterile production)
WFI CFU-10/ml pH 5-7	-Pyrogen free only ((not more than 0.25 IU of endotoxin per ml) -Used as a solvent in parenteral preparation Note: it is not intended to be sterile but should comply with the test for a limit of Endotoxin (Pyrosen free). i.e it is pyrogen-free but not sterilized as per IP. -Not contain an added substance
SWFI ^{content provided by ThePharmapedia.com}	– Sterilised & packed in a single-dose glass container of type I & II; maximum. of 1 (one) Litre capacity. i.e both pyrogen-free and sterilized – Used as a solvent for powder or Injection. -Not contain an added substance
BWFI _{notes by The Pharmapedia}	-Sterile WFI contains one or more suitable Bacteriostatic agents & packed in a single or multiple-dose glass container & Maximum 30 mL capacity. -Contain added substance
Water BET(bacterial endotoxin test)	it is WFI (Sterilised) & free from an endotoxin – used in the test for Bacterial Endotoxin (Pyrogen) Test.
Highly purified water	High Purity water is a Distilled water filtered through 0.45 m membrane & Conductivity not more than 0.15 S/cm @ 25 degrees centigrade.

type & Use of Pharmaceutical waters

Purified water

Purified Water is used as an excipient/solvent in the production of non-parenteral preparations and in other pharmaceutical applications, such as cleaning of certain equipment and non-parenteral product-contact components.
Purified Water must meet the requirements for ionic and organic chemical purity and must be protected from microbial contamination.
The source or feed water for the production of Purified Water is Drinking Water/potable water (CFU 500/ml).
Purified water comply with standards given in monographs of official books (pharmacopoeia). The Limit for the microbial population for purified water is 100 CFU/mL.
Purified water is commonly produced by ion exchange, reverse osmosis (RO), ultrafiltration or electro-deionization processes and distillation.

Water for Injection (WFI)

A pH of WFI is about 5. it may range from 5.0 to 7.0.
Storage of WFI: at room temperature 24 hrs; & for more than 24 hrs it must store at 80-degree centigrade
WFI is not sterile water and is not a final dosage form.

Water for injection (WFI) is used as an excipient in the production of parenteral and other preparations where product endotoxin content must be controlled and in other pharmaceutical applications, such as cleaning of certain equipment of parenteral production.
WFI in bulk is prepared from water or from purified water by distillation in an apparatus of which the parts in contact with water are of neutral glass, quarts or suitable metal & which is fitted with an effective device to prevent the entrainment of droplets.
WFI complies with the test for purified water with additional requirements for bacterial endotoxins (not more than 0.25 IU of endotoxin per ml), conductivity & total organic carbon.

Highly purified water

Highly purified water is a unique specification for water found only in the European Pharmacopoeia.
This grade of water must meet the same quality standard as water for injections (WFI), including the limit for endotoxins.
Current production methods include, for example, double-pass RO coupled with other suitable techniques such as ultrafiltration and deionization.
High Purity water is a Distilled water filtered through 0.45 m membrane & Conductivity not more than 0.15 S/cm @ 25 degree centigrade.