FAQs About Water for Injection

  1. Is it possible to produce hot water from a membrane system?
    No, it is not possible to produce hot water from the technology itself, but the water could be heated once it is in the tank, or even before by adding a heat exchanger between the generation system and the storage tank.
  2. Can an existing purified water (PW) system be converted to a WFI generation system?
    In theory a purified water system can be converted to a WFI generation system from a water quality perspective but in reality there may be issues when it comes to validating the system and ensuring that the regulators are happy that it is producing WFI and not PW
  3. Where would you recommend installing an online microbial monitor?
    Puretech would recommend installing an online microbial monitor at the return end of the distribution loop, before the water goes back into the storage tank.
  4. Are there any situations/processes where you would not recommend the membrane technology?
    Not really, EUR Pharmacopeia, US and JP Pharmacopeia all allow membrane technology, but Puretech would recommend checking with your regulator to see whether they would accept membrane technology to obtain WFI, and if they will not it could be considered a risk.
  5. Does regulatory guidelines allow cold WFI distribution ?
    Yes. Water temperature is not one of parameters for WFI but certain applications that WFI is used for will require hot water.
  6. Is it necessary to sterilise a membrane WFI generation system, from a regulation point of view (given that WFI is it a sterile media)?
    Puretech recommends regular heat sanitisations of generation systems to ensure they deliver the quality of water required, especially from a bacteria perspective.
  7. Is further treatment of WFI required when storing it in a tank?
    No further treatment is required for stored WFI, but Puretech recommend that if you are storing it cold to maintain a temp below 20°C.
  8. Is it mandatory to have a second stage RO membrane to produce WFI or just advisable?
    Puretech recommends a twin pass secondary membrane but it is not mandatory to produce WFI.
  9. What’s the best sanitisation method for WFI in cold distribution ?
    There are three options for the sanitisation of WFI in cold distribution – hot water >80°C, super-heated and ozone – all of which are tried, tested and reliable. There are pros and cons for each one so ultimately the decision will depend on how the water is being used in your facility, down time, costs etc.
  10. Can you advise how to remove the bacterial endotoxin using only membranes?
    Puretech would not guarantee meeting the bacterial endotoxin required for WFI without an ultra-filter and regulators would not accept a system without ultra-filtration.