Solid Dosage Form Manufacture via Twin Screw Extrusion

The application of continuous extrusion via twin screw extruders (TSE) for pharmaceutical solid dosage form production is growing in popularity as a preferred option to more traditional granulation techniques. The TSE offers several advantages as a method of granulation formation including continuous processing with reproducibility and combination of a variety of process steps within one piece of equipment, i.e. distributive and dispersive mixing, granulating and devolatilization. The production method provides gentle product handling at short residence time and low temperature. Two methods in which the extruder is used for solid dosage form production are wet granulation and hot melt extrusion. With its special versions of the ZSK twin screw extruders suitable for the production of pharmaceutical compounds, Coperion is one of the pioneers in the development of pharmaceutical extrusion. Coperion has references for pharmaceutical extruders in the sizes ZSK 18 to ZSK 70. The good mixing behavior and the devolatilization possibilities of the co-rotating twin screws make this system particularly suitable for pharmaceutical extrusion. During wet granulation and hot melt extrusion liquids and powders must be fed accurately and continuously throughout the run and refill operations in order to ensure consistency of formulation, constant throughput, proper order of mixing ingredients and regulated mass transfer. Coperion K-Tron Pharmaceutical Loss-inweight (LIW) feeders are used in conjunction with extruders in the pharmaceutical industry for both liquid and powder feeds. Typically, feed streams are introduced to the extruder in a “starve-fed” manner, where the rate is set by the feeders and is independent of the extruder screw speed.