Rational development of taste masked oral liquids guided by an electronic tongue

Human taste testing is often associated with ethical concerns, organizational and validation issues. Electrochemical sensor array systems, so called electronic tongues, offer an alternative to assess the taste of multi-component liquid formulations. Therefore, it should be investigated how an electronic tongue can be implemented in the rational development of taste masked formulations. Taste masking of bitter tasting quinine hydrochloride (QH) in a liquid formulation was carried out by screening sweetening agents (sucrose, glucose, fructose, mannitol, sucralose, sodium saccharin, acesulfame potassium, and monoammonium glycyrrhizinate), strong and weak cation ion exchange (IE) resins (Amberlite™ IRP69, Amberlite™ IRP88, and Indion 234), and soluble complexing agents (α-, β-, hydroxypropyl-β-, sulfobutyl ether-β- and γ-cyclodextrin and maltodextrin). Amberlite™ IRP88 showed the best binding capacity for quinine (1.9 g quinine/1 g IE). The addition of sulfobutyl ether-β-cyclodextrin (SBE-β-CD) could significantly reduce the bitter taste of QH (79% reduction of free QH). The SBE-β-CD formulation was further improved by adding sodium saccharin as secondary taste masking agent. It could also be shown that presence of strawberry flavor and the preservative domiphen bromide does not affect evaluation of taste masking efficiency. The introduced stepwise approach was shown to be applicable to rationally develop novel taste masked formulations.