Twin screw extruder can produce any of these products
Operators can use HME to form solid dispersions in a continuous process but, unlike spray drying, solvent evaporation, and coprecipitation techniques, HME does not require organic or hazardous solvents. Nor does the process require water or drying equipment. For these reasons, HME enables manufacturers to reduce expenses and conserve space on the plant floor. In addition, the process could replace solid-dosage unit operations such as blending, granulation, and particle sizing, says Firouz Asgarzadeh, principal scientist at Evonik.
HME is not limited to producing solid dosage forms, however. Operators can use the process to create multilayer transdermal patches, implants, dissolvable strips, and foams. Any twin screw extruder can produce any of these products, only the die and the downstream handling must be adjusted, says Martin.
HME also can modify drugs’ characteristics. Many new active pharmaceutical ingredients (APIs) have big molecular structures and are consequently difficult to dissolve, but HME can enhance these substances’ solubility, according to Peter von Hoffmann, general manager of engineering plastics and special applications at Coperion. The high temperatures and shear in the HME process can bring poorly soluble drugs with a crystalline structure into a stabilized, amorphous state that is more soluble. HME also can maintain a drug’s crystalline structure, but make the crystals finer and the particle size smaller to improve solubility.