Critical view on drug dissolution in artificial saliva: A possible use of in-line e-tongue measurements

Proper monitoring of drug's dissolution is a prerequisite for assessing of taste masking efficacy of pharmaceuticals. Corresponding dissolution procedure is likely to be performed with water. Since the objective of these tests is to examine fate of a pharmaceutical formulation in oral cavity, this choice of solvent seems unsuitable because physical and chemical properties of human saliva are quite far from those of water. Obviously, dissolution profiles registered in water may differ significantly from what really happens with a drug in a mouth cavity. In order to address this discrepancy we examined three different compositions of artificial saliva in dissolution test context in present study. It was found that certain compositions preclude the employment of traditional UV–vis spectroscopy as a detection tool due to strong light scattering in the media caused by viscosity and protein composition modifiers. This issue was circumvented by the use of in-line applied potentiometric multisensor system (e-tongue) and the potential of this new approach for more biorelevant dissolution tests was demonstrated with two model formulations of quinine and ibuprofen.