Quality control and analytical techniques for biopharmaceuticals.

Biopharmaceuticals are complex products and to ensure their batch-to-batch consistency and continuing quality the use of a combination of complementary analytical tests is required. Regulatory guidelines indicate quality attributes of different product classes to be included in the specifications for product release. Whilst the continuing development of sophisticated physicochemical techniques make them increasingly powerful for defining product identity, integrity, purity and the consistency of the manufacturing process, the results generated are not easily related to the biological activity. Consequently, a bioassay is normally required in the quality control to determine the potency, that is, the quantitative measure of the product's ability to cause a specific biological effect in a defined biological system. A wide, and rapidly increasing, range of bioassay systems exist, each type with particular advantages and disadvantages.