Modifying the bitterness of selected oral pharmaceuticals with cation and anion series of salts.
OBJECTIVE
NaCl has proven to be an effective bitterness inhibitor, but the reason remains unclear. The purpose of this study was to examine the influence of a variety of cations and anions on the bitterness of selected oral pharmaceuticals and bitter taste stimuli: pseudoephedrine, ranitidine, acetaminophen, quinine, and urea.


METHODS
Human psychophysical taste evaluation using a whole mouth exposure procedure was used.


RESULTS
The cations (all associated with the acetate anion) inhibited bitterness when mixed with pharmaceutical solutions to varying degrees. The sodium cation significantly (P < 0.003) inhibited bitterness of the pharmaceuticals more than the other cations. The anions (all associated with the sodium cation) also inhibited bitterness to varying degrees. With the exception of salicylate, the glutamate and adenosine monophosphate anions significantly (P < 0.001) inhibited bitterness of the pharmaceuticals more than the other anions. Also, there were several specific inhibitory interactions between ammonium, sodium and salicylate and certain pharmaceuticals.


CONCLUSIONS
We conclude that sodium was the most successful cation and glutamate and AMP were the most successful anions at inhibiting bitterness. Structure forming and breaking properties of ions, as predicted by the Hofmeister series. and other physical-chemical ion properties failed to significantly predict bitterness inhibition.
Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104, USA. keast@monell.org
Russell S J
RS
Keast
Paul A S
PA
Breslin
D000249:Adenosine Monophosphate / Q000494:pharmacology; D000284:Administration, Oral; D000328:Adult; D000704:Analysis of Variance; D000838:Anions / Q000037:antagonists & inhibitors; D002412:Cations / Q000037:antagonists & inhibitors; D018698:Glutamic Acid / Q000494:pharmacology; D006801:Humans; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry; D019346:Sodium Acetate / Q000494:pharmacology; D013649:Taste / Q000187:drug effects* / Q000502:physiology
D000838:Anions; D002412:Cations; D004364:Pharmaceutical Preparations; D018698:Glutamic Acid; D000249:Adenosine Monophosphate; D019346:Sodium Acetate