Quantitative evaluation of the bitterness of commercial medicines using a taste sensor

The bitterness of 11 commercial medicines was evaluated both by a multichan nel taste sensor and in human gustatory sensation tests with 15 volunteers, For basic drugs with amino groups in the molecule, such as quinine, there was a comparatively strong relative response electric potential (mV) of cha nnels 1 or 2, those containing negatively charged membranes and the bittern ess determined by human gustatory sensation tests. The suppression of the b itterness of quinine by sucrose and aspartame could be quantified using the artificial taste sensor and the results concurred with those from gustator y sensation tests. The usefulness of the sensor was thus confirmed for this type of compound, Anionic drugs, such as diclofenac sodium or salicylic acid gave rise in a n egative response electric potential in channels 5 or 6, those containing po sitively charged membrane, seemed to be useful information even though thei r tastes are being sour rather than bitter. For drugs with both an amino (cationic) group and carboxylic acid (anionic) group in the molecule, such as theophylline, caffeine, and metronidazole, the relative response electric potential (mV) of channels containing negati vely charged membranes was not increased, even though bitterness was observ ed in human gustatory sensation tests, Therefore, a different design of mem brane component is required for more general evaluation of the bitterness o f various medicines.