Screening solid-state properties

With the above method, MiCoS has been applied to glybenclamide ASD screening with four enteric polymers at five drug loadings (Hu et al. 2013). Based on both the solid state properties and kinetic solubility, HPMCAS LF was recommended to prepare glybenclamide ASD at up to 40 % of drug loading. 

There are many different techniques that could be used to evaluate the solid-state properties of the API under study. Typically, cheaper and less technically challenging techniques such as thermal techniques (TGA and DSC) are utilized to screen materials. If these initial techniques show a multitude of species, or are inclusive, then typically a more advanced technique such as X-ray powder diffraction or SSNMR can be employed, if available to the project team. A brief description of the most commonly used solid-state techniques will follow. 

Several factors detennine how efficient impurity atoms will be in altering the electronic properties of a semiconductor. For example, the size of the band gap, the shape of the energy bands near the gap and the ability of the valence electrons to screen the impurity atom are all important. The process of adding controlled impurity atoms to semiconductors is called doping. The ability to produce well defined doping levels in semiconductors is one reason for the revolutionary developments in the construction of solid-state electronic devices. 

The properties of the defect solid state are fundamental to our understanding of all reacting systems involving a solid in fact, there is little of the metallurgical and chemical industries which is not based on the chemical properties of defect solids. A little reflection will make this so obvious that there is no necessity to enumerate specific examples even the electrical industry depends on the ability to produce materials having controllable defect properties, e.g. luminescent materials for fluorescent lamps and cathode-ray tube screens, oxide materials for cathode coatings, a variety of semi-conductors for resistors, rectifiers, detectors and photoelectric devices. 

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