Hot-nielt extrusion (HME) is currently applied in the pharmaceutical field for manufacturing a variety of dosage forms and formulations such as granules, pellets, tablets, implants, transdermal systems, and ophthalmic inserts 1. The HME process has been evaluated to improve the dissolution rate of poorly water-soluble drugs by forming solid dispersions and solid solutions, to control or modify the drug release and to mask the bitter taste of the drug 2. For pharmaceutical applications, HME offers many advantages over traditional processing techniques, such as; (a) It is a solvent free processing method for solid dispersions and thus it is environment friendly and cost effective, (b) It offers the possibility of continuous processing and thus an efficient scale up from small scale laboratory extruder to large scale production size melt extruder. Increasing the dissolution rate of poorly water-soluble drugs is one of the major challenges in dosage form development. One approach is the formation of a solid dispersion of drug with a hydrophilic excipient. The ideal type of solid dispersion for increasing dissolution is a glass solution, in which the amorphous drug has a lower thermodynamic barrier to dissolution together with a maximally reduced particle size. In addition, the intimate presence of a hydrophilic excipient can increase wetting and lead to super-saturation in the diffusion layer. A glass solution is formed when two or more components are entirely miscible in the molten state and cool to form an amorphous one-phase system. However, to form a glass solution that is physically stable over prolonged periods of time the glass transition temperature (Tg) should be higher than the storage temperature (at least 50 °C above the storage temperature). This study focuses on the characterization of physico-chemical properties of a poorly water model drug and a hydrophilic model polymer to assess its suitability to manufacture solid dispersion/solution by hot melt extrusion process in order to increase the solubility of drug in the aqueous medium and consequently improving its oral bioavailability.
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