Coperion: Focus on extrusion lines for the pharmaceutical industry

“Pharmaceutical Hot Melt Extrusion” Congress

At its in-house congress on “Pharmaceutical Hot Melt Extrusion”, held on April 15, 2010, Coperion GmbH, Stuttgart/Germany, provided around 100 guests from the pharmaceutical industry with a compact overview of this special, rapidly growing application. Pharmaceutical experts from both industry and science explained, by way of case examples and the results of R&D projects, the vast area of application for hot melt extrusion in the pharmaceutical industry. These lectures were complemented by presentations of Coperion, formerly Werner & Pfleiderer, demonstrating the experiences gained over the past two decades with special pharmaceutical versions of its ZSK twin-screw compounder.

Coperion counts among the pioneers of hot melt extrusion. Its ZSK compounders are used in the pharmaceutical industry, for example, for the continuous production of tablet mixtures, transdermal patches with active ingredients or adhesives for medical appliances, e.g. ostomy bags. Further possible applications for hot melt extrusion are the manufacture of medical compounds with delayed ingredient release, the processing of insoluble substances or substances that are more difficult to dissolve, encapsulation and taste masking. For the further development of Hot Melt Extrusion for pharmaceutical applications, Coperion has entered into an alliance with ISP Pharmaceuticals, Madrid, Spain. For its part, ISP contributes both its know-how in the field of excipients (e.g. polymers and disintegration agents) and its experience with formulations and material economy, while Coperion makes available its know-how in the design and manufacture of extrusion systems for pharmaceuticals and its many years’ experience in process engineering.

One of the prerequisites for hot melt extrusion in pharmaceutical applications is the use of an extrusion line that is in keeping with good manufacturing practice (GMP). This requirement is fully met by the special pharma version of Coperion’s ZSK MEGAcompounder PLUS: it is self-cleaning and has virtually no dead spots in the entire system. All parts that come into contact with the product are manufactured from proven materials with specially treated surfaces. The system uses only FDA-approved oils and lubricants. In addition, the extruder meets the very stringent workplace safety requirements of the pharmaceutical industry. Congress participants were able to gain a practical impression of these special features during a demonstration of hot melt extrusion in Coperion’s test lab: organic pigments of Rudolf Wild GmbH & Co. KG., Heidelberg/Germany, were worked into a Soluplus® matrix polymer from BASF SE, Ludwigshafen/Germany.

The technology of hot melt extrusion
Hot melt extrusion technology is used for the mixing of active pharmaceutical ingredients (APIs) into a matrix. To this end, the starting materials, i.e. the APIs, the matrix substances and the additives, are fed continuously in exactly the required quantities via gravimetric feeding systems into the process section of the ZSK MEGAcompounder PLUS, where they are melted with the aid of the co-rotating twin screws and then gently mixed and homogenized at low temperature and in only a few seconds. The screw shafts of the ZSK MEGAcompounder PLUS feature different, process-optimized screw flights for each extruder zone. If required, further solid or liquid substances can be fed downstream into the extruder barrel via lateral feeding devices. A vacuum venting system is often installed just upstream of the discharge section in order to release trapped air, volatiles and/or solvents and thus obtain a bubble-free melt. The finished compound can then be directly extruded and pelleted by the ZSK MEGAcompounder PLUS via an extrusion die plate or further processed in a downstream calender.

The entire extruder system of the ZSK MEGAcompounder PLUS, comprising the extruder barrel, the screw and the screw flights, is of modular design. Drawing from their extensive know-how based on years of experience, the pharma application experts at Coperion configure the extruder system exactly in accordance with the user’s individual compounding requirements.

Advantages of hot melt extrusion in pharmaceutical applications
Compared with conventional processes, continuous hot melt extrusion affords the manufacturer a great many advantages:

• It is also suitable for the processing of substances that are insoluble or very difficult to dissolve in water, as a stable and uniform dispersion of the substances is obtained in the matrix during the compounding process.
• It can increase API content and also improve the bioavailability of the APIs.
• It is a solvent-free process, thus waiving the need for certain production stages, e.g. drying.
• Its efficient mode of operation ensures extreme homogeneity, while the short residence time and low operating temperature ensure gentle compounding.
• It is suitable for the production of medical masses with tailored or delayed release systems.

These processing advantages are complemented by a great many advantages in terms of the actual practical application of hot melt extrusion. Coperion’s compounders for hot melt extrusion are distinguished by their economic efficiency and, owing to their continuous mode of operation, by their typical reproducibility of quality and exact adherence to formulation. The machine control system, with its on-line monitoring capability, ensures accurate observation of process parameters and generates the necessary production records. Moreover, thanks to its extremely compact design, the ZSK MEGAcompounder PLUS takes up only negligible floor space. As the twin screws in the ZSK are largely self-cleaning, changeover from one formulation or product to another can be effected without difficulty. The modules of the compounding system are clearly arranged, easy to operate and readily accessible for cleaning and maintenance purposes.

The user services offered by Coperion for pharmaceutical hot melt extrusion
So that users may optimally exploit the aforementioned advantages of hot melt extrusion, Coperion offers comprehensive backup through its specialized process engineers. Their extensive know-how guarantees reliable process control and accurate adaptation of process parameters to other sizes of machine. Coperion can also draw on years of experience in the mathematical modelling of the processing parts of the extruder, thus ensuring an accurate forecast of the process when it comes to using the compounder for new applications.

More Information: www.coperion.com