Pharmaceutical literature does not offer any common definition for the term ‘quality’. The idea implied in most definitions is the idea that the drug product has to meet customer needs. Customers cannot assess the quality of their drugs and this is the reason why governments have to step in with rules and regulations to ensure the quality of medicines.
A study of the history of drug regulations reveals that most
laws were enacted in response to tragedies that occurred when patients received
drugs that were contaminated or not properly processed or incorrectly labeled.
This led to a focus by drug makers on Quality Control – the process of testing
the quality of products manufactured in their facilities.
As time evolved, and pharmaceutical processes grew more
complex, it gradually came to be realized that no process is perfect all the
time, and there are drifts from normal functioning. The best testing methods
may miss detecting a problem because the destructive nature of the testing
means only a few samples drawn at random can be tested. Thus, there was a
realization that relying on mere testing of products at the end of the
manufacturing process is an ineffective (and costly) way of trying to ensure
quality.
According to regulatory bodies across the world, high-quality
drug products are those that can be relied upon to deliver the desired clinical
effects with consistency. Consumers of medicines need to know for sure that the
drug products they are consuming are of good quality, safe for consumption, and
will be effective in relieving them of their ailments. This quality can be
guaranteed only if the products have it built into them right from the very
first stage of design of the product and process. Realization of this basic
principle led to the International Conference on Harmonization (ICH) in 2002,
introducing a hitherto unheard-of term in the drug processing field – the
concept of ‘Quality by Design’ or QbD.
Quality by Design
The ICH guideline Q8 (R2) Pharmaceutical Development defines
QbD as, “A systematic approach to development that begins with predefined
objectives, emphasizes product, process understanding and process control,
based on sound science and quality risk management.”
To achieve the objective of QbD, it is important to
understand product characteristics and study process characteristics using a
combination of prior knowledge and experimental studies. From this data
generated during product development, it becomes possible to decide which
quality parameters in starting materials are the most important, and which
critical processing factors need to be controlled to achieve a product with all
the desired quality attributes.
The ICH Q10 guideline says that a Pharmaceutical Quality
System is one that “assures that the desired product quality is routinely met,
suitable process performance is achieved, the set of controls are appropriate,
improvement opportunities are identified and evaluated, and the body of
knowledge is continually expanded.”
Fig: Quality by Design
In other words, a robust pharmaceutical quality system is
the key to supplying customers with high-quality drugs. Such a system has the
following characteristics:
• Aligned with requirements of current Good Manufacturing
Practices (cGMP)
• Science-based and risk-based
• Comprehensive
• Proactive and accountable
Developing such pharmaceutical quality systems is the key to
efficiently meeting patient requirements. Because they deliver consistent
quality, these systems also serve to increase the confidence of regulatory
bodies about the organization’s commitment to quality.