In an EDQM paper published in Pharmeuropa in March 2015 the topic production of WFI (water for injections) by means of membrane technologies (reverse osmosis coupled with other suitable techniques) is discussed again and not excluded any more. So far distillation is the only permitted procedure for the production of WFI in Europe. It was already pointed out in the paper on the revision of Annex 1 published in February that alternative procedures for the manufacture of WFI might become possible.
The first part of the new document describes the history of the long lasting discussion of the question whether other procedures than distillation should be allowed for the production of WFI. In the end this led to the creation of a new monograph of highly purified water (HPW). This is water with WFI quality produced by means of membrane-based technologies. But its possible applications were very restricted.
Now it looks as though the Ph. Eur. Water for Pharmaceutical Use (WAT) Working Party has concluded that there is evidence to support a revision of the WFI monograph in the European Pharmacopoeia (0169). As reasons for this change are indicated for example advances in the "non-distillation technology" and improvements in the design of the water-production systems as well as an advanced process control. But it is acknowledged that the design and maintenance of any water-production system plays an important role in ensuring the security of the produced water. The manufacturer is responsible for compliance with GMP requirements. Presumably, existing guidance documents must be complemented for this by the appropriate stakeholders. Furthermore, quality assurance and monitoring should extend to storage and distribution processes for WFI.
As a result the highly purified water monograph (1927) would be made redundant and be deleted. Furthermore, the inclusion of water for dialysis in the WFI monograph could also be contemplated.
The draft monograph is available on the EDQM webpage for free, after registration. The main change reads:
WFI is produced either by [..destillation, . ].or
by reverse osmosis, which may be single-pass or double-pass, coupled with other suitable techniques such as deionisation and/or ultrafiltration.
Correct operation monitoring and maintenance of the system are essential.
The EDQM already organised a special webinar on April 22nd where this topic has been discussed.
The original document mentioned above discusses the alternative production methods for WFI.