ABSTRACT
It is apparent from the preceding chapters that extruders and high-intensity
twin-screw mixers are highly flexible and efficient mixing devices that are suitable for the manufacture of products that demand consistency and superior
quality. This requirement is particularly true with pharmaceuticals where the
precise delivery of active entities to a specific site within the human body is critical, and variations in delivery could either reduce the effectiveness of the medication, or lead to toxic levels that could put the patient at risk. As a result,
it has been the primary objective of the pharmaceutical industry and the
regulatory bodies to ensure that drug products distributed to the public are
manufactured under Good Manufacturing Practices (GMPs) and consistently
meet stringent quality requirements. Because single-screw and twin-screw
mixers are equipped with precisely designed and machined hardware and
controls, these devices provide the user with manufacturing capabilities that
easily meet process validation requirements as mandated by regulatory
agencies. Given these desirable attributes, it is expected that single-screw
and twin-screw extruders, or variations thereof, will soon become standard
pharmaceutical manufacturing equipment, and the application of extrusion
processes in pharmaceutical development and production will be firmly
established. Extruders do not only provide products that are superior in quality
to those manufactured by any other comparable conventional manufacturing
equipment, but may also be cost-effective because they allow continuous processing, provided that optimal conditions that exploit the full potential of
the devices are met. It is anticipated that significant effort will be devoted to extensive characterization and optimization of formulation variables and
processing parameters to accommodate the ever-increasing quality require-
ments that pharmaceutical drug products must satisfy to gain regulatory
approval and marketing authorization. Concurrently, it is expected that equip-
ment manufacturers will continue, with inputs from pharmaceutical scientists
and engineers, to further refine machine engineering designs and to build advanced pieces of equipment that keep up with the quality requirements and
performance needs of drug products that support a seamless transition from a
development environment to a production setting. Some equipment-related
design considerations that are likely to be investigated and the impact they will
have on dosage form manufacturing are discussed below.
