RECENT ADVANCES IN HOT MELT EXTRUSION TECHNOLOGY

Melt extrusion process which is well known in the polymer and food industry is now being used for pharmaceutical manufacturing to create innovative new formulations and is a continuous process of mixing and designing moldable materials. It is one of the most widely applied processing techniques useful for preparing solid dosage forms, granules, pellets, suppositories, implants, stents, ophthalmic inserts, transdermal and transmucosal drug delivery systems. Also this technique is used in Taste Masking, Solubility Enhancement, and Sustained-Release Pellets Manufacturing. Several advantages over other techniques include cost and performance benefits such as a faster path to FDA approval for new compounds, possible re-indication for existing active pharmaceutical ingredient (APIs), controllable bioavailability, possible lower doses, and probable lower production costs. Hot-melt extrusion efficiently produces solid molecular dispersions with considerable advantages over solvent-based processes such as spray drying and co-precipitation. In general, high temperatures have to be applied to extrude polymeric carriers. Melt extruded dosage forms are complex mixtures of API, excipients, and polymer carrier which are blended using single and twin-screw extruders, molten thermoplastic polymers during the extrusion process can function as thermal binders and/or drug release retardants. A typical extrusion line consists of the material feed hopper, basic extruder, the extrusion die, the calibration units, the haul-off, the saw, and finally the treatment devices for final finishing and handling. This technology is suitable for both high dose and potent compounds. Thus, this review summarizes in detail all the aspects of melt extrusion.