Scope and Application of Hot Melt Extrusion in the Development of Controlled and Sustained Release Drug Delivery Systems.

Controlled-release drug delivery systems (CRDDS) are more beneficial than conventional immediate release (IRDDS) for reduced intake, prolonged duration of action, lesser adverse effects, higher bioavailability, etc. The preparation of CRDDS is more complex than IRDDS. The hot melt extrusion (HME) technique is used for developing amorphous solid dispersion of poorly water soluble drugs to improve their dissolution rate and oral bioavailability. HME can be employed to develop CRDDS. Sustained release delivery systems (SRDDS), usually given orally, can also be developed using HME. This technique has the advantages of using no organic solvent, converting crystalline drugs to amorphous, improving bioavailability, etc. However, the heat sensitivity of drugs, miscibility between drug-polymer, and the availability of a few polymers are some of the challenges HME faces in developing CRDDS and SRDDS. The selection of a suitable polymer and the optimization of the process with the help of the QbD principle are two important aspects of the successful application of HME. In this review, strategies to prepare SRDDS and CRDDS using HME are discussed with its applications in research.