ABSTRACT
Introduction 719
Product Forms 721
Sampling 721
Physical Methods 722
Chemical Methods 725
Spectroscopy 726
Chromatography 727
Validation 728
Microbiology 729
Efficacy 730
Stability 730
Summary 730
References 731
INTRODUCTION
Any description of the techniques for product quality control should start with an
agreed definition of the term. The description almost requires that the question
“Why do quality control at all?” be asked. In the modern times of Good
Manufacturing Practices (GMP) (1,2), speed to market, just-in-time processes,
and government mandated development and production, quality control of the
finished product is almost an expensive complication delaying the release of
finished products. The reality is that even with the best systems in place, with
all of the supplier qualifications completed, with a regular auditing process,
and with government oversight, there is still a need to ensure that material
produced will meet the expectations of the final consumer. One could probably
find many definitions of quality and a number of systems to ensure product
quality. For the purposes of this chapter, quality is defined as meeting the custo-
mer’s expectations every time. Such an approach is described, for example, by
Juran and Godfrey (3), who indicate two aspects of quality. The first definition
covers the features of products that meet customer needs and thereby provide
customer satisfaction. The second is the freedom from deficiencies, which
could result in the need for rework or lead to product failure and therefore
customer dissatisfaction. This latter aspect has, for the most part, been addressed
through conformance to specifications. This grew from a belief that if something
meets specifications, it will satisfy the customer. Newer approaches with greater
emphasis on customer focus require that a broader view be taken, that quality is
not always captured only in specifications. From such a view grows the definition
of quality control as a universal managerial process for conducting operations so
as to provide stability-to prevent adverse change and to maintain the status quo.
The quality control process maintains this stability by evaluating actual perform-
ance, comparing actual performance to goals and acting on differences found (3).
This chapter does not pretend to cover all of the aspects one must understand,
address and control to have a quality system or even a quality control system.
It also does not cover quality assurance (defined as verification that control is
being maintained), quality improvement, “total quality management,” or other
extensions of these concepts and philosophies. This is an ever-evolving area
and today’s definitions are likely to change again in the future. Many volumes
have been written on that. Quality control is a program with the steps taken by
the developer and manufacturer to support delivery to the customer’s expec-
tation. Quality control focuses on control during operations and meeting the
goals for operations. Quality assurance is involved at later steps and interacts
with a broader range of functions involved in the product life cycle.
