Hot-Melt Extrusion: Case Study and the Fundamentals of Miscibility

Traditional blending processes in the pharmaceutical industry are operated at room temperature. In recent years, melt mixing has received a great deal of interest, mainly due to the challenge associated with the ever increasing number of poorly soluble drugs. In addition to the dissolution enhancement, melt mixing also possesses several other advantages. It is a solvent free process; it can be realized by using a continuous extruder, which is commonly used in the plastic and processed food industries. Our experimental data show that API and polymeric excipients can form one phase at the elevated temperature. The drug may remain in amorphous form or recrystallize after the mixture is cooled to room temperature, depending mostly on the formulation. In addition, our results suggest that melt mixing can be applied to significantly increase or slow down drug’s release rate, which cannot be achieved if the same components are blended at room temperature.