Twin Screw Extruders for Pharmaceutical Applications

In the phamaceutical industry, continuous processing techniques are being developed to give productivity and product quality improvements over the traditional batch processing alternatives.

Constructed according to the specific requirements of the pharmaceutical industry, the MP-PH is available in a range of sizes, from bench-top models suitable for processing batches of a few hundred grams to large scale production units with capacities of several hundred kilograms per hour.

The 'clamshell' barrel design allows access to all contact parts for cleaning and maintenance. CIP facilities are also available. The versatility of the MP-PH series allows a wide variety of raw materials to be processed under a variety of processing conditions.

The Baker Perkins MP-PH series of twin screw extruders can be used for continuous production of solid dosage formulations by either continuous granulation, extrusion spheronisation or melt extrusion techniques.

The MP-PH twin screw mixer extruder is the ideal choice for improving productivity and product quality through continuous processing in the pharmaceutical industry.

Benefits of Twin Screw Extrusion

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A single step mixing and extrusion process can make the production route more efficient and improve productivity.	The 'clamshell' barrel design allows easy access to the agitators and interior barrel surfaces for cleaning.	Elimination of organic solvents used in coating processes results in cost savings and reduces environmental impact.
Narrow residence time distribution results in uniform product quality	Batch to batch variation is eliminated by continuous production	Flexibility in handling a wide range of raw materials.
Continuous operation coupled with the low volume of the mixing chamber lead to reduced inventories of work in progress	Elimination of intermediate steps such as drying reduces capital cost, space requirements and energy consumotion	Reduced level of binder addition over comparable batch operations.

Melt Extrusion

Production of controlled release formulations by extrusion spheronisation usually involves an energy intensive drying stage. When the active ingredient is sufficiently thermally stable to permit compouding into a molten binder then production by this route eliminates the drying stage.

The MP-PH range of closely intermashing co-rotating twin screw extruders has been specially designed to meet the specilist needs of the pharmaceutical industry. Constucted in wear resistant stainless steel, according to cGMP guidlines, the MP-PH is suitable for the melt extrusion of many pharmaceutical compounds. The mixer is electrically heated to promote melting of the binder without excessive mechanical energy input. The molten mass can be extruded onto a cooling band or roller to form a flaked product. This can then be ground to a free flowing powder for tableting or filling to capsules.

Continuous Granulation

Wet granulation is a common technique for preparation of free flowing porous granules which are readily compressed into tablets.

Continuous wet granulation combines solid components and binding liquids inside the twin screw mixer extruder. The granules formed can be dried in a continuous dryer. The MP-PH range of closely intermeshing co-rotating screw extruders is suitable for the wet granulation of many pharmaceutiacl compounds.

Extrusion Spheronisation

Production of spheroids by extrusion spheronisation is widely used in the manufacture of controlled release dossage forms. The particles formed are smooth surfaced, round and exhibit a narrow and reproducible size distribution. The density and friability of such particles are also well defined. These characteristics result in the particles being easily and uniformly coated and lead to well defined dissolution profiles. In addition to the the pharmacokinetic properties of the microspheres, the regular beads exhibit excellent flow properties and are able to be accurately filled into hard gelatin capsules.

High drug loadings are necessary to achieve sustained blood levels of active pharmaceutical over an extended time period. Drug loadings of 60-85% in a polymeric matrix are possible with the use of extrusion spheronisation techniques.

The use of a twin scew extruder allows combination of the wet massing and extrusion stages into a single unit. The dry powder blend is fed to the extruder where it is mixed with a liquid binder. The resulting wet mass is then extruded through a die plate to form 'noodles' before spheronisation.

Credentials

MP-PH extruders are manufactured in Baker Perkins' modern factory in Peterborough, where the latest machining centres ensure precise tolerance to accurate designs.

Baker Perkins has combined a wealth of pharmaceutical experience and the latest 3D CAD programmes to engineer a range of 40 - 100mm MP-PH extruders - a range complemented by Baker Perkins' 19mm and 30mm laboratory extruders.

At its dedicated and fully equiped Technology centre in Peterborough, Baker Perkins is able to develop and demonstrate a wide range of pharmaceutical extrusion processes.

Baker Perkins' comprehensive customer service is supported by a 24 hour help line and an extensive stock of spare parts for rapid response to the needs of customers throughout the world