New insights into the disintegration mechanism and disintegration profiling of rapidly disintegrating tablets (RDTs) by thermal imaging

In current studies, the disintegration process of tablets has been studied by thermal imaging. The study covers two major aspects; first, new revelations in the mechanism of tablet disintegration, and second, the development of disintegration test as a multi-point test by new thermometric and non-thermometric methods. The study has been carried out on fexofenadine rapidly disintegrating tablets (FEX RDTs) in a dark room cabinet fitted with a Fluke thermal imager and using water as the disintegration medium. The studies exhibit the existence of endothermic peaks during the early penetration of water in FEX RDTs. These endotherms are prominent at the starting point when the disintegration has just started, or the tablet has been just exposed to the water. Such endotherms have not been reported earlier for tablets and can be considered as a part of the wicking mechanism during disintegration. In later stages, when the water has completely wet the tablet, the endotherms are superimposed by exotherms. The endotherms or exotherms have also been used as a measurement of disintegration in the form of a new thermometric parameter, "area under temperature curve" (AUTC). Non-thermometric disintegration profiling by residual and subtraction methods is also performed. Among these, disintegration by the residual method, i.e., disintegration (residual) is newly introduced. In the end, the principal component analysis (PCA) describes the relationship between various disintegration methods, particle size distribution, and dissolution. PCA reveals that AUTC is the best method for studying the disintegration behavior of FEX RDTs.