Melt-congealing technique

The melt-congealing technique has been practiced in the manufacture of wax-based suppositories for over 100 years. The basic concept of melt-congealing process was employed by Sekiguchi et al. ... 

Wax microparticles have been prepared primarily by aqueous and non-aqueous melt dispersion techniques or spray congealing/spray drying. These techniques are briefly reviewed below. 

It is noteworthy that the use of the earliest analytical techniques for the systematic study of essential oils, such as SG, relative density, optical activity, and refractive index or melting, congealing, and boiling points determinations, is generally applied for the assessment of pure compounds and may be extended to evaluate essential oils composed of a major compound. Classical methods cannot be used as stand alone methods and need to be combined with modern analytical techniques, especially GC, for the assessment of essential oil genuineness. 

Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and infrared spectroscopy are the common techniques used in the characterization of the structure of the congealed solid. Thermal analytic methods, such as DSC and differential microcalorimetric analysis (DMA), are routinely used to determine the effect of solutes, solvents, and other additives on the thermomechanical properties of polymers such as glass transition temperature (Tg) and melting point. The X-ray diffraction method is used to detect the crystalline structure of solids. The infrared technique is powerful in detecting interactions, such as complexation, reaction, and hydrogen bonding, in both the solid and solution states. 

Spray congealing is a melt technique of high versatility. In addition to manufacture multiparticulate delivery... 

Passerini N, Albertini B, Perissutti B, Rodriguez L (2006) Eyaluation of melt granulation and ultrasonic spray congealing as techniques to enhance the dissolution of praziquantel. International Journal of Pharmaceutics 318(2) 92-102. 

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