Quality control is the part of GMP that is concerned with sampling, specifications, testing and with organization, documentation and release procedures, using validated methods implemented by trained and experienced personnel.

The quality control process is not confined to laboratory operations, but must be applied to all decisions concerning the quality of a product. Quality control staff must therefore sign all manufacturing procedures that are relevant to product quality. Quality control staff will also monitor environmental conditions that have an effect on product quality. Each holder of a manufacturing licence should have a quality control department. This department must have staff who are clearly responsible for all quality control activities. They must have access to suitable facilities to perform all the testing that is required.

The independence of quality control from production is considered fundamental. This means that the quality control manager should not report to the production manager. Likewise, the production manager should not report to the quality control manager. Legislation in different countries deals with this issue in different ways. Quality control departments need sufficient resources to carry out their responsibilities.

Adequate resources should include: sufficient numbers of trained and experienced staff an appropriately designed laboratory, suitably equipped to enable all the quality control functions to be carried out in accordance with specifications.

Ideally, the head of the quality control department should report directly to the managing director of the company. This means that for key decisions on product quality there is no interference from manufacturing staff. An alternative to this, which might in some circumstances be preferable, is that the quality controller reports to a professionally qualified technical director who is also responsible for production activities. This position does rely on the professionalism of the jobholder. The advantage of this second arrangement is that it encourages a scientific and professional review of the product quality against the standards and product use. This scientific evaluation of the product may not be possible for a chief executive who has no scientific background.

All samples must be taken by methods and trained personnel approved by the quality control department. Records must be made of all sampling and testing and any deviations fully recorded and investigated. Samples (when taken) must be representative of the whole batch under consideration. The samples must be taken in accordance with a sampling plan, and in such a way as not to change the quality of the material being sampled. When containers have been sampled, they need to be labelled as such. The equipment used for sampling should be carefully cleaned between use, to ensure that it has no adverse affect on the result of the testing to be done. This cleaning will also assist in preventing cross-contamination. All activities relating to sampling should be described in a SOP, together with the safety precautions required.

The quality control department should authorize all documentation that has an effect on product quality. This will include all SOPs as well as master documents for production and quality control batch documentation. A complete review of all batch documentation, relating to production and quality control, should be undertaken before the decision to release the product for sale is taken by the authorized person. The authorized person must check that the product conforms to the established specifications and the registered product details before releasing the product for distribution.

The quality control department must retain sufficient samples of all materials in the batch and of the finished product, as described in the relevant SOP. The retained sample is used for ongoing stability testing and to permit, as necessary, a future examination of the product in case of a product complaint or recall. The quantity of the product to be retained will be determined by reference to the stability testing programme and the extent of testing required. Generally, the quantity is at least twice that required for full testing.

The quality control department has the responsibility for handling all product complaints and recalls, including the management of any recall procedure, which must be available in the form of a written SOP. This area of activity deals with the less positive aspects of quality management. However, professional handling of any complaints or recalls is extremely important. There is a complete module devoted to this issue in this training programme.