In most cases, drugs (hydrophobic drug) or vitamins with poor water solubility possess low oral bioavailability which is considered as a challenge for pharmaceutical and food supplements industry.

Spray chilling or spray congealing is another form of solid dispersion where the melted mass is atomized into droplets, which quickly solidify in cool air. Spray congealing is gaining much attention nowadays due to its efficiency in the enhanced oral bioavailability of such drugs. Also, spray congealing is considered as an inexpensive and environmentally friendly technique as it requires no solvent as a carrier, unlike other techniques. Furthermore, it is also possible to control particle size, which is considered as a very important parameter for enhancing bioavailability by increasing surface area. Microspheres are characteristically free-flowing powders having a particle size ranging from 1-1000μm. Such encapsulated microspheres help to improve patient compliance and convenience. 

Various polymeric carriers are used for encapsulation such as polyvinyl pyrollidone (PVP) and polyethylene glycol (PEG), polyoxyethylene-polyoxypropylene-polyoxyethylene etc.