Non-human tools for the evaluation of bitter taste in the design and development of medicines: a systematic review

• Electronic taste sensing systems give relative taste statement and should be validated with human taste panel tests. Once validated, these sensors can be used for early screening of taste of pure APIs and optimisation of taste masked preclinical formulations in industry.
• Brief access taste aversion model, (mainly rats) have showed good correlation with human taste data. This model can be used for early screening of taste of pure API and formulated products.
• In vitro dissolution/release studies can be used to support other tools in early screening of taste of API/coated solid dosage forms where it is not feasible to test non liquid forms.

Taste evaluation is a crucial factor for determining acceptance of medicines by patients. The human taste panel test is the main method used to establish the overall palatability and acceptability of a drug product to a patient towards the end of development. Non-human in vitro and in vivo taste-evaluation tools are very useful for pre-formulation, quality control and screening of formulations. These non-human taste assessment tools can be used to evaluate all aspects of taste quality. The focus of this review is bitterness because it is a key aspect of taste in association with the development of medicines. In this review, recent in vitro (analytical) and in vivo (non-human) tools are described for the assessment of the bitter taste of medicines. Their correlations with human taste data are critically discussed. The potential for their use in early screening of the taste of active pharmaceutical ingredients (APIs) to expedite paediatric formulation development is also considered.