Interest in hot extrusion techniques in pharmaceutical applications is growing rapidly.
Hot extrusion (HME) is a widely used technique in the plastics industry and has recently been shown to be a viable method for preparing many types of dosage forms and drug delivery systems. Hot extruded dosage forms are complex mixtures of active drugs, functional intermediates and processing aids. HME offers many advantages over traditional pharmaceutical processing techniques, including the absence or reduction of solvents. Possibility to carry out several processing steps in one process. Continuous operation and the possibility of creating solid dispersions and obtaining better bioavailability.
The HME technique is an attractive alternative to traditional processing methods. HME offers many advantages over other pharmaceutical techniques. The molten polymers during the extrusion process can function as thermal binders and act as drug depots or drug release retarders when cooled and solidified. Solvents and water are not necessary, thus reducing the number of processing steps and eliminating time-consuming drying steps. The matrix may be pressurized to achieve greater matrix density. The intense mixing and shearing imposed by the rotating extruder screws breaks up and distributes the aggregates of suspended particles in the polymer melt. This process results in a more uniform dispersion, is continuous and efficient. HME can be used to improve the bioavailability of medicinal substances, especially those with low water solubility by creating molecular dispersions.