Page 64 - Quality control of pharmaceuticals (07-PA 704)

METHOD REVALIDATION
As the method under validation is required to be used as written, any modification
requires revalidation
For chromatographic methods, significant changes include:

• Changes in the product
• Instrumental changes
• Reagent changes
• Procedure changes
• Technological changes e.g. development in columns and instrumental

technology.

Stability of Drug Substances
Stability definitions:
The capacity of a drug or product to remain within established specifications of
identity quality, purity in a specific period of time.
Or
The capacity or the capability of a particular formulation in a specific container to
remain within particular chemical, microbiological, therapeutically, and
toxicological specifications.
USP defines stability of pharmaceutical products as the extent to which a product
retains, within specified limits and throughout its period of storage and use, the
properties and characteristics that it possessed at the time of its manufacture.
The purpose of stability testing is to provide evidence on how the quality of a drug
substance or drug product varies with time under the influence of a variety of
environmental factors, such as temperature, humidity, and light, and to establish a