Close this search box.

Glossary of terms used in High Purity Water in Pharma and Biopharma Applications

From cleaning equipment to preparing injectables solutions, the implementation of water in the pharmaceutical industry is as diverse as it is significant. To get a macro perspective of how water as a resource is consumed and applied in pharmaceutical processes, we have built an exhaustive glossary of terminologies to explain simple and complex processes used in day-to-day pharmaceutical operations.

Grades of Water in the Pharmaceutical Industry 

Potable Water

Water obtained from public sources such as municipal water supply, wells, etc. It is used in the initial stages of chemical synthesis and equipment cleaning. As the source is subjected to seasonal changes, it must be treated before usage. 

Soft Water

Water that is free of salts of metal such as calcium, magnesium, iron, etc. It ensures no interference with cleaners such as soap and does not precipitate in pipes or tanks.

Purified Water

Grade of water used in pharmaceuticals. It must meet specific ionic, microbial, and organic chemical requirements. Purified water is largely used as an excipient in the pharmaceutical manufacturing processes.

Water for Injections

It is the resulting product of further purification of pharmaceutical purified water by the process of distillation. The process eliminates bacterial endotoxins from the water. This grade of water is largely used for manufacturing parenteral drugs that directly come in contact with the bloodstream.

Important Terminologies

Bulk Water

Water used in pharmaceutical processes produced on site where it is used.

Packaged Water

Water used in pharmaceutical processes that is sterilized, produced, packaged to preserve their microbial quality for longer shelf life and meant for the purpose of distribution.

USP Monographs

An accepted standard for identity, quality, purity, strength, labelling, packaging for substances that are used in compounded processes.

Water With No Monographs

Water for Injections

It is a grade of water in the pharmaceutical industry and the resulting product of further purification of pharmaceutical purified water by the process of distillation. The process eliminates bacterial endotoxins from the water. This grade of water is largely used for manufacturing parenteral drugs that directly comes in contact with the bloodstream

Water for Hemodialysis

It is also referred to as the Dialysate and is used in dialysis, which is a common process administered to patients with kidney-related issues. The Dialysate is a solution of ultra-purified water, electrolytes, and salts such as sodium and bicarbonate. The primary objective of the solution is to draw out toxins from the body.

Pure Steam

Steam condensation that is free of additives and meets the specification for injectable quality water is called pure steam. It is commonly used in pharmaceutical sterile manufacturing.

Sterile Purified Water

It is suitably sterilized and packaged water that is free of anti-microbial agents. 

Sterile Water for Injection

It is sterile, non-pyrogenic, and distilled water for intravenous administration. It usually has a pH of 5.5.

Bacteriostatic Water for Injection

It is sterile water with a final concentration of 0.9% benzyl alcohol. It is used for in the dilution or dissolution of medication.

Sterile Water for Irrigation

It is water for injection that is packed in large quantities (usually in containers with a capacity of more than 1L). It is hypotonic with a pH of 5.5 and is commonly used as a fluid replacement with suitable additives introduced to it.

Sterile Water for Inhalation

It is suitably packaged sterile water that is used in making inhalation solutions.

Pharmaceutical Water Purification Systems

Pre-Treatment Systems


Refers to the introduction of chlorine, a strong oxidant, which eliminates impurities such as viruses and bacteria from the water.


Using a filter media based on the raw water parameter to eliminate impurities such as Total Suspended Solids (TSS) is referred to as filtration. It is one of the most traditional methods of water purification.


After using the chlorine to get rid of viruses and bacteria in the water, the chlorine needs to be extracted out of it to protect the RO membrane of the piping. The process used to do that is called chlorination.

De-chlorination can be achieved in two ways:

  • Activated Carbon Filter: A carbon compound is used to draw out and eliminate the chlorine present in the water.
  • SMBS (Sodium Meta Bisulphite) Dosing System: Using Sodium Metabisulfite in correct doses also helps remove chlorine from the water. It is often considered a cheap and efficient way to achieve de-chlorination. 


Introduces softeners to treat the water and facilitate better ion exchange which salts of impurities like sodium and magnesium into Sodium Chloride ions which results is soft water.

Ultra-filtration (UF)

Water is made to flow through a hollow fibre membrane which reduces the Slit Density Index of the water, thereby removing the risk of the said slit choking the RO membranes.

Dosing System

The process of adding external agents in water to obtain specific results. It can be achieved by using the following systems:

  • Anti-Scalent Dosing: Sodium hexametaphosphates are used to break up the silica, sulfate precipitates and several other minerals that leads to fouling.
  • pH Correction Dosing: Ensures the elimination of carbon dioxide and keeping the important properties of the water intact. Acids like hydrochloric acids, acetic acid and others are used in different concentrations to achieve the same.
  • SMBS Dosings: SMBS are added to eliminate chlorine from the water.

Post Treatment Systems

Reverse Osmosis

A high-pressure pump is used to force the water flow through a semi-permeable membrane to achieve purification. The following systems are usually used in the process to ensure ‘clean’ membranes.

Hot Water Sanitization (HSRO)

Purified hot water with a temperature of 80°C is used to eliminate contaminants of microbial nature from the RO system.

Chemical Sanitization (CSRO)

An acid cleaner, such as citric acid, is used to remove inorganic contaminants from the membrane.

Electro-Deionization (EDI)

Two membranes, anode (-ve charge) and cathode (+ve charge), are used. When electricity is passed through the water, the anions are attracted to the anode and cations are attracted towards the cathode. The resultant product of the process is de-ionized water.

Ultraviolet Disinfection

Uses UV rays to destroy the DNA of micro-organisms such as algae, mould, etc, thereby inhibiting their growth. The resultant product of this process is ‘pure water’.

Multi Column Distillation Plant (MCDP)

A specially structured set of columns based on the FINN-AQUA design. It uses the principle of inter-stage heat exchange to facilitate the production of sterile distilled water. The resultant product of this is called Water for Injection of WFI.


Activated Carbon

A variant of carbon that is adequately treated to expand its absorption capabilities. In the pharmaceutical industry, it is used to absorb impurities from the water, such as low-molecular-weight organic materials and bacterial endotoxins, and to oxidize different additives.


Substances added to the water to control, enhance, remove, avoid, and adjust different pharmaceutical processes.

Organic Scavengers

Weakly basic anion exchanging resins with macro reticular (or large net-like structures) that are capable of removing negatively charged organic materials and endotoxins from the water.

Microbial Retentive Filtration

Uses membrane filters with pore size larger than that of ultrafilters. It is used to eliminate microorganisms and particles without restricting the flow of the water.

UV Light

Low-pressure light with a wavelength of 245 nm, is widely used in pharmaceutical processes to control the microbial concentration of the water.


Different impurities are separated from the water based on the difference in the volatility (vapour pressures). This can be done via thermal vaporization, mist elimination, or water condensation.

Storage Tanks

Ensures the availability of an adequate and constant supply of water to cater to different manufacturing processes.

Distribution Systems

A network of pipings and other arrangements ensures a constant flow of water and is usually equipped with recirculating abilities.

You might find these interesting:

Share this post:

For 20 years, we’ve been the go-to problem-solvers for high-purity and injectable process applications in the pharma and biopharma industry. We are relentless about continuous process improvement and upskilling, elevating ourselves and our technology so you can get the job done more efficiently with cost optimisations. Use the form below to schedule a call back from our team.

This field is for validation purposes and should be left unchanged.