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.