Water Purification Process for Pharmaceutical Use


In the realm of pharmaceutical production, water plays a crucial role not only in medication manufacturing but also in dissolutions, cleanings, and disinfections, among other applications. The pharmaceutical industry’s demand for water is substantial, accounting for approximately 60% to 80% of the total water consumption in the sector.

The concept of “pure water” takes center stage in this context. Natural water sources rarely provide water in its pure form, and due to its chemical properties, water can dissolve, absorb, or suspend various compounds. Consequently, the water purification process is a vital aspect of pharmaceutical production, aimed at achieving optimal water quality. However, water for pharmaceutical use must begin as potable water suitable for human consumption.

To attain this quality, a two-tier decontamination process is employed: first, adhering to regulations for obtaining potable water, and subsequently, meeting the criteria set by internationally recognized pharmacopeias such as the European Pharmacopoeia (Ph Eur) or the United States Pharmacopeia (USP). This meticulous process ensures that the water can be used as a raw material in pharmaceutical applications.

Types of Water for the Pharmaceutical Industry

Pure Water – Purified Water (PW)
Pure water serves as an appropriate resource for manufacturing products that require high-quality water with minimal biological content. This type of water is commonly used in pharmaceutical liquid and solid formulations and serves as a base for producing even higher-quality water, such as water for injection.

Highly Purified Water – Highly Purified (HPW)
Similar to purified water, highly purified water is utilized in preparing pharmaceutical products that necessitate water of superior biological quality, excluding cases where water for injection is required.

Water for Injection – Water for Injection (WFI)
Water for injection is indispensable for sterile preparations intended for parenteral administration. It also finds application in equipment cleaning for sterile production and certain chemical processes.

Water Treatment Processes for Pharmaceutical Use

The specifications for water used in pharmaceutical applications are established by pharmacopeias. The selection of a water treatment process depends on various factors, including the quality of the source water, the type of water required, the necessary quantity, operational costs, and maintenance considerations.

The pharmaceutical industry commonly employs the following treatment methods to obtain suitable water:

  • Reverse Osmosis (RO): This process involves pressurizing water through a semipermeable membrane, allowing water molecules to pass through while retaining contaminants such as salts, acids, bases, colloids, bacteria, and endotoxins.
  • Ion Exchange or Deionization: Water is passed through ion exchange resins to remove ions from salts present in the water. Cations are removed by H+ ions, and anions are removed by OH- ions. The resins are regenerated using acids and alkalis, and equipment can be mixed-bed or separate (cationic and anionic resins).
  • Ultrafiltration (UF): In this process similar to reverse osmosis, water passes through a semipermeable membrane. The water flows parallel to the porous ultrafiltration membrane, and differential pressure drives water through the membrane, rejecting most contaminants except low molecular weight species like ions.
  • Distillation: Distillation involves the purification of water through phase change. Water is vaporized, leaving behind most contaminants. The produced vapor is then condensed. It’s important to note that some low molecular weight contaminants can be carried along with the water vapor.
  • Continuous Electrodeionization: This technology effectively removes waterborne salts by combining ion exchange membranes, ion exchange resins, and a continuous direct current electric field.

The water purification process for pharmaceutical use is a complex endeavor that involves multiple stages and technologies to ensure water is of the utmost quality. This clean water serves as the foundation for the production of safe and effective pharmaceutical products that contribute to human health and well-being.