4.1 Although some continuous processing is used in the pharmaceutical industry (for example, purified water production, inherently continuous individual unit operations such as dry granulation and compression), these operations are generally operated in isolation and do not deliver the potential benefits of an integrated continuous manufacturing operation. The FDA Guidance for Industry PAT document specifically identifies that the introduction of continuous processing may be one of the outcomes from the adoption of a science-based approach to process design.

4.2 This guide does not:

4.2.1 Suggest that continuous production is suitable for the manufacture of all pharmaceutical products.

4.2.2 Provide guidance on issues related to the safe operation of a continuous process or continuous processing equipment. It is the responsibility of the user of this standard to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use.

4.2.3 Recommend particular designs or operating regimes for continuous manufacturing.

4.3 Appendix X1 includes a table comparing the characteristics of continuous and discrete or batch processes.

1.1 This guide introduces key concepts and principles to assist in the appropriate selection, development and operation of continuous processing technologies for the manufacture of pharmaceutical products.

1.2 Particular consideration is given to the development and application of the appropriate scientific understanding and engineering principles that differentiate continuous manufacture from traditional batch manufacturing.

1.3 Most of the underlying concepts and principles (for example, process dynamics and process control) outlined in this guide can be applied in both Drug Substance (DS) and Drug Product (DP) processes. However it should be recognized that in Drug Substance production the emphasis may be more on chemical behavior and dynamics in a fluid phase whereas for drug product manufacture there may be a greater emphasis on the physical behavior and dynamics in a solid/powder format.

1.4 This guide is also intended to apply in both the development of a new process, or the improvement/redesign of an existing one.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.