Water used in pharmaceutical manufacturing must meet some of the most rigorous purity standards of any industrial application. United States Pharmacopeia (USP) purified water and water for injection (WFI) specifications cover a comprehensive range of contaminants — yet the rapid emergence of PFAS as environmental contaminants has revealed gaps in traditional pharmaceutical water quality frameworks that the industry is now beginning to address.
USP Water Categories and Their Standards
The USP defines several water quality grades for pharmaceutical applications, each with progressively stringent specifications:
- Purified Water (USP): Used for non-parenteral (non-injectable) drug manufacturing, equipment rinsing, and reagent preparation. Must meet conductivity, TOC, and microbial limits.
- Water for Injection (WFI, USP): Used in parenteral drug manufacturing and final rinsing of containers and equipment that contact sterile drugs. More stringent specifications; traditionally produced by distillation, now also by reverse osmosis in most markets.
- Sterile Purified Water and Sterile WFI: Terminally sterilized versions of the above.
Notably, current USP specifications for purified water and WFI do not include specific limits for PFAS. This is primarily because USP specifications were established before PFAS emerged as a recognized pharmaceutical water concern, and the USP monograph revision process is complex and time-consuming.
Why PFAS Are a Concern in Pharmaceutical Water
PFAS can enter pharmaceutical water systems through multiple pathways:
Source water contamination: Pharmaceutical facilities that draw from municipal water supplies or groundwater in PFAS-affected areas face PFAS in their feed water. The effectiveness of their treatment systems in removing PFAS determines whether these compounds reach the product water.
PFAS-containing materials in water systems: Historically, some pharmaceutical water systems incorporated PFAS-containing components: fluoropolymer tubing (PTFE, PFA, FEP), PTFE gaskets, and fluoropolymer-lined vessels. While fluoropolymers in finished form are generally considered stable, there is growing evidence that PFAS can leach from these materials under certain conditions, particularly when new or damaged.
PFAS in cleaning and sanitizing agents: Some cleaning agents used in pharmaceutical facilities contain PFAS for wetting or surface-active properties. These can contaminate water systems if not fully rinsed.
Regulatory and Industry Response
The pharmaceutical industry’s PFAS concerns are primarily driven by:
- FDA and ICH guidance evolution: As environmental PFAS awareness grows, regulatory agencies are reviewing whether pharmaceutical water standards should include PFAS testing and limits
- EU Environmental Quality Standards: European pharmaceutical manufacturers face stricter environmental compliance requirements that may drive water treatment upgrades
- Customer and patient concerns: Pharmaceutical manufacturers responding to market pressure are proactively testing water and implementing PFAS controls
Treatment Options in Pharmaceutical Water Systems
Pharmaceutical water systems already incorporate technologies that provide meaningful PFAS removal:
Reverse osmosis: The transition of WFI production from multi-effect distillation to RO (now allowed in most pharmacopoeias) provides inherent PFAS rejection of 90–99%.
Distillation: Multi-effect distillation and vapor compression distillation provide effective PFAS removal, as PFAS do not volatilize with steam (though carry-over can occur at very high feed concentrations).
Electrodeionization (EDI): Commonly used as a polishing step in USP water systems; provides limited PFAS removal depending on the specific compound’s charge and size.
Dedicated PFAS removal media: Ion exchange resins and activated carbon can be added as pre-treatment to existing systems for enhanced PFAS reduction.
Implications for Pharmaceutical Users
Patients receiving intravenous medications or other parenteral products manufactured with inadequately treated water in PFAS-contaminated areas may face additional PFAS exposure from treatment — an irony given that medical treatment is meant to improve health outcomes. While the industry is beginning to address this gap proactively, it represents an important area for continued regulatory attention and voluntary testing.