Author(s): Donald C Monkhouse, John L Lach
Using the instrumental techniques of diffuse reflectance spectroscopy, differential thermal analysis, and X-ray analysis, it was possible to characterize the type of bonding forces involved in the minuscular drug systems prior to the dissolution process. Hydrogen bonding and van der Waals' forces accounted for the rapid desorption of the drugs from the adsorbent surface. A decrease in particle size was suggested as a major factor improving the dissolution rate of these equilibrated systems. Two polymorphic forms of indomethacin and probucol were identified as being present in the samples, the proportion of the metastable form being dependent on the percentage of fumed silicon dioxide added to the system.