The bio-pharmaceutical industry demands exacting detail in design, development,
operation, quality, and just about every other aspect of the business.
As such, there is a degree of specialty in most every field of endeavor
in this industry. This book was developed to try to accelerate the learning
process for the application of automation in bio-pharmaceuticals. The
authors' hope is that the content of this book will help scientists and engineers
continue to contribute to the manufacture of high-quality medicines
via improving process control and on-line availability of information
while reducing costs, cycle time, and process variability.
Some readers may come into this industry with previous automation
experience. Others may be in the bio-pharmaceutical industry, but have
limited automation knowledge. In either case, the authors strived to bring
the reader to a more thorough understanding of the topics.
This book is supplemented by a wealth of reference materials in the industry.
Each chapter contains a list of recommended reference materials.
TABLE OF CONTENTS Chapter 3.5 - Water-for-Injection: WFI
Process Description and Challenges
Water-for-Injection (WFI) must meet strict guidelines for purity. The
system that produces and distributes the WFI must be able to maintain
this high level of purity. This is usually accomplished by sanitizing the
system at high temperatures, followed by maintaining continuous flow
through the distribution system at high temperature.
The typical WFI system, as pictured in Figure 3-3, consists of a WFI generation
unit, a supply tank, and a distribution loop. The generation system
is typically some form of multi-effect evaporator and condenser. WFI is
passed from the generation system to the supply tank. To prevent stagnation
or "dead spots," the water is continuously circulated, at high temperature,
through a distribution loop. Individual use points, or "drops," draw
WFI from the circulation loop, sometimes through a heat exchanger to
cool the water for process needs.
A variety of evaporation units and condensers may be used for generation
of WFI. The generation unit is typically supplied as a fully instrumented
skid, with its own dedicated controls.
