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FIGURE 3 Vapor compression water-for-injection (WFI) still. Source: Courtesy of Lonza Biologics,
Portsmouth, New Hampshire, U.S.A.
In the end, the grade of water the CIP system uses for the pre-rinsing and
cleaning the equipment and piping in agiven circuit is up to the designer.Softened
water, USP purified, or USP WFI are the typical choices in the U.S. highly purified
water or RO/DI water (that are not necessarily tested to the USP compendial
monographs) may be the water of choice for cleaning equipment that is used for
manufacturing APIs and oral dosage forms.
CHOOSE YOUR WATER WISELY
Ankers
As water usage increases and the cost of water increases, the designer needs to
carefully select the grade of water for both the wash and rinse phases of the CIP
cycle. It is typical to choose the purest water available in the facility and justify its
usage for all phases by saving money on capital costs such as piping and controls.
But, at U.S. $1 to U.S. $2 per liter for WFI and other highly purified waters, you pay
for the additional capital cost of connecting to another, lower cost water in the first
couple of cycles. CIP systems also tend to “compete” with the process users for the
compendial water due to the higher instantaneous flow rates required in CIP
systems occurring at the same time alarge process user is drawing from the loop.
This can cause process-scheduling problems that can extend the batch times. Save
the compendial waters for the final rinses.
For example, softened water is agood choice for the cleaning and intermediate
rinses in most biotech facilities that produce parenterals. Potable water is very
common as the primary cleaning solvent and rinse water in APIs and solid oral
dosage process. The latest edition of the USP states, in the section “Water for
Pharmaceutical Purposes” that “Drinking water may be used in the early stages