Quality Assurance and Method Validation - Forensic Applications of Gas Chromatography - page 49

5

Quality Assurance and
Method Validation

5.1 Quality Assurance

There are many definitions for quality assurance; however, one of the best
is 'a planned and systematic pattern of all actions necessary to provide con-
fidence that adequate technical requirements are established; that products
and services conform to established technical requirements and that satisfac-
tory performance is achieved'. 1 Essentially, this can be simplified to 'fitness
for purpose'.

5.2 Quality Control

Quality control is a process of inspection, analysis and action required to
ensure quality of a process or product. For example, if we consider a packet
of paracetamol (acetaminophen) that can be purchased from a chemist or
pharmacy, how do we know that this product is safe for use and that it will
safely rid us of our headache? The answer is quality control. Quality control
is a set of procedures that are intended to check that a product or service is fit
for purpose and conforms to a defined set of quality criteria that is set by an
external regulatory body or a customer.
Each paracetamol (acetaminophen) tablet that we purchase for our head-
ache will usually contain 500 mg of the active compound (i.e., paracetamol)
plus excipients that will ease administration of the active compound into the
body. A paracetamol tablet will also typically contain maize starch, dioctyl
sodium sulfosuccinate (docusate sodium), colloidal anhydrous silica, magne-
sium stearate and polyvinylpyrrolidone (povidone). Both the active compound
and the other excipients will be tested against a particular Pharmacopoeia. A
Pharmacopoeia is a topic that contains instructions on how to identify sam-
ples and provides information on the preparation of medications.
Pharmacopoeias tend to be published by learned pharmaceutical societ-
ies of a particular country. For example, the US Pharmacopoeia (USP) is pro-
duced by the US Pharmacopoeial Convention and the National Formulary
(USP-NF); the British Pharmacopoeia (BP) is produced by the British
Pharmacopoeia Commission Secretariat of the Medicines and Healthcare
Products and Regulatory Agency (MHRA). Other pharmacopoeias are