REVIEW ON THE PHARMACEUTICAL APPLICATIONS OF HOT MELT EXTRUDER

Compared to single-unit dosage forms, oral multi particulate drug-delivery systems like pellets, granules offer advantages in terms of a more even and predictable distribution and transportation in the gastro-intestinal tract. As the number of poorly soluble drugs has risen sharply in recent years, techniques for improving the solubility, and potentially, the bioavailability have become increasingly important. Melt extrusion technology represents an efficient pathway for increasing the solubility of poorly soluble drugs. In the drug the active forms a solid dispersion where the drug is presented in an amorphous state and molecularly dispersed in the carrier. This leads to an increase in solubility, as no lattice energy has to be overcome during dissolution. The particle size is reduced to the molecular level and the carrier increases the wetting of the drug. Scientists have tried to address such issues by various pharmaceutical interventions like various pelletizations, granulation and hot melt extrusion techniques available to prepare drug loaded spherical particles or granules. Amongst all extrusion is the most common method which utilized in formulation of beads and pellets. Limitations related to bioavailability and site specific drug delivery can be over come by this technique. This technology has gained focus because of its easy of operation and fast processing. Extrusion is widely utilized in formulation of sustained release, controlled release delivery system. Melt extrusion is considered to be an efficient technology with particular advantages over solvent processes like co-precipitation for the manufacture of a variety of dosage forms and formulations such as granules, pellets, tablet s, suppositories, implants, stents, transdermal systems and ophthalmic inserts. This process is also useful from an ecological standpoint to produce solid dispersions efficiently without degradation. Potential drawbacks like the influence of heat stress and shear forces on the drug needs attention while doing extrusion. This review article describes the melt extrusion equipment, process and polymers used for formulation of various API using various pharmaceutical-grade polymers.