* * * INSIGHT * * *
Overview of the Lyophilization Process
By
Thomas A. Jennings, Ph.D.
ABSTRACT: There may be individuals who visit our web site who are not familiar at all with the lyophilization process. As a consequence, they may find the current issues of INSIGHT to be difficult to understand and wish for a more general overview of the process and its associated instrumentation and equipment. It is to those individuals that we dedicate this issue of INSIGHT.
The very first thing that a person should understand is the definition of the term lyophilization. Such a definition will not only give a general description of the process in one sentence but serve as a basis for expanding one’s knowledge of the subject. Without the aid of a definition, one often finds themselves cast adrift upon a sea of terms or technical jargon that leads to confusion rather than understanding. It is surprising to this author, to see the look of pain on an individual’s face who has used the term lyophilization a countless number of times but is lost to provide a definition.
The lyophilization process is defined as “ A stabilizing process in which a substance is first frozen and then the quantity of the solvent (generally water) is reduced, first by sublimation (referred to as the primary drying process) and then desorption (known as the secondary drying process) to values that will no longer support biological activity or chemical reactions”[1]. While the actual definition contains but 37 words - not counting those contained in the parentheses - less than one quarter of the words ( those italicized) are considered key words and are essential to understanding of the nature the lyophilization process. The following will provide a brief discussion of the above key terms. In order to simplify the discussion, the example used will be a solution comprising of water as a solvent and a number solutes (constituents).
Volume 1 Number 9 November 1998
5 Pages 1 Reference No Figures
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