Pharmaceutical Water for Injection Equipment

Pharmaceutical Water for Injection (WFI) equipment is specifically designed to produce water that meets the pharmaceutical standards for injection.

Equipment Components

- Pretreatment System
- Raw Water Tank: Used to store raw water, with its capacity determined based on actual production needs. The material is generally food-grade stainless steel to prevent contamination of the raw water.
- Raw Water Pump: Provides the driving force to transport raw water from the tank to subsequent treatment units. It must ensure a stable flow rate and appropriate pressure to allow the raw water to pass smoothly through each pretreatment device.
- Multi-Media Filter: Typically contains filtration media such as quartz sand and anthracite coal, which remove larger particulate impurities like suspended solids, sediment, and colloids, providing initial purification of the raw water.
- Activated Carbon Filter: Utilizes the adsorption properties of activated carbon to effectively remove organic matter, residual chlorine, odors, and some heavy metals from the water, improving its chemical stability and sensory qualities.
- Softener (Optional): If the raw water has high hardness, a softener can use ion exchange resin to remove hardness ions such as calcium and magnesium, preventing scale formation in subsequent equipment and ensuring normal operation and water quality.

- Reverse Osmosis System (Optional but Common)
- High-Pressure Pump: Provides sufficient pressure for the reverse osmosis process, forcing water through the reverse osmosis membrane. The pressure typically ranges from 1 to 10 MPa, depending on the membrane model and requirements.
- Reverse Osmosis Membrane Module: The core component of the reverse osmosis system, consisting of multiple layers of reverse osmosis membranes. It removes the vast majority of salts, organic matter, microorganisms, and other impurities from the water, reducing the conductivity of the product water to a low level, with a desalination rate generally reaching 98% to 99% or higher.

- Ion Exchange System (Optional)
- Mixed-Bed Ion Exchanger: After reverse osmosis treatment, if further reduction of ion content in the water is required, a mixed-bed ion exchanger can be used. It contains a mixture of cation and anion exchange resins, capable of removing trace remaining ions from the water, further reducing conductivity and achieving higher purity.

- Distillation System
- Multi-Effect Distillation Unit: This is the key equipment for producing pharmaceutical Water for Injection. It typically consists of three-effect, four-effect, or more evaporators. Taking a three-effect system as an example, the first-effect evaporator uses external steam to heat the feed water, generating steam that serves as the heat source for the second-effect evaporator. The steam from the second effect then acts as the heat source for the third-effect evaporator. Through multiple evaporation-condensation cycles, impurities, microorganisms, and endotoxins are effectively removed, resulting in high-purity Water for Injection.
- Condenser: Its main function is to condense the steam generated by the final-effect evaporator into liquid water. Condensers come in various structural forms, such as shell-and-tube or plate types, and use a cooling medium (e.g., cooling water) to remove heat from the steam, causing it to liquefy.

- Storage and Distribution System
- Water for Injection Storage Tank: Made of 316L stainless steel, with the inner surface electropolished and passivated to minimize the leaching of metal ions. The tank should have excellent sealing to prevent external contamination, as well as insulation or heating devices to maintain the water temperature within an appropriate range and avoid microbial growth. The tank is also equipped with a breather, typically a 0.2 μm hydrophobic filter, to balance internal and external pressure while preventing airborne microorganisms and impurities from entering.
- Transfer Pump: Usually made of 316L stainless steel, used to deliver Water for Injection from the storage tank to various points of use, such as formulation tanks in drug production workshops or bottle washers. The transfer pump should provide a stable flow rate and appropriate pressure, ensuring no leakage or contamination.
- Piping System: Pipes are primarily made of 316L stainless steel, with electropolished inner surfaces and strict welding requirements to ensure smooth and even interiors. Valves are generally diaphragm valves, which offer good sealing, are easy to clean and disinfect, and effectively prevent microbial growth and impurity ingress.

Quality Control and Maintenance

- Water Quality Monitoring: Equipped with a range of water quality monitoring devices, such as conductivity meters, Total Organic Carbon (TOC) analyzers, and bacterial endotoxin testing instruments. Conductivity meters monitor ion content, TOC analyzers detect the total amount of organic carbon in the water, and bacterial endotoxin testers ensure that the endotoxin content of the Water for Injection meets pharmaceutical standards (generally required to be less than 0.25 EU/mL).
- Equipment Cleaning and Disinfection: Regular cleaning and disinfection of the equipment are crucial for maintaining water quality. For filters in the pretreatment system, backwashing can be used to remove trapped impurities. For the distillation system and storage/distribution system, methods such as pure steam sterilization, hot water disinfection, or chemical disinfectants can be employed to kill microorganisms and prevent biofilm formation.
- Component Inspection and Replacement: Regularly inspect various components of the equipment, such as reverse osmosis membranes, ion exchange resins, filter cartridges, and valve seals. Replace them based on their service life and actual operating conditions to ensure normal equipment operation and stable water quality.