A new method for evaluating the bitterness of medicines by semi-continuousmeasurement of adsorption using a taste sensor

We describe a new method for the evaluation of the bitterness of medicines by semi-continuous measurement of adsorption using a multichannel taste sen sor or 'electric tongue'. The bitterness of 10 basic medicines was evaluate d by both the taste sensor and in human gustatory sensation tests with 11 v olunteers. The sensor part of the taste sensor consists of eight electrodes made of lipid/polymer membranes. Three variables were obtained from the ta ste sensor data: sensor output (S), the change of membrane potential caused by adsorption, corresponding to aftertaste (C), and the ratio C/S. These v ariables were used to predict an estimated bitterness score in multiple reg ression analysis. Semi-continuous measurement of C (every 30 s up to 150 s) was adopted as an additional explanatory variable, and the attenuation rat e of C was defined as C. These data were also subjected to multiple regress ion analysis. The correlation coefficient (r) estimated for the bitterness score predicted by the taste sensor, using C for channel 2 and CIS for chan nel 4, and the score obtained by human gustatory sensation, was 0.824. This value was greater than that obtained using C/S for both channels 2 and 4 ( 0.734). The method described in the present study seems to offer good predi ctability for the evaluation of bitterness.