Taste-Masking Effect of Chlorogenic Acid (CGA) on Bitter Drugs Evaluated by Taste Sensor and Surface Plasmon Resonance on the Basis of CGA-Drug Interactions

The purpose of this study was to evaluate the taste-masking effects of chlorogenic acid (CGA) on bitter drugs using taste sensor measurements and surface plasmon resonance (SPR) analysis of CGA drug interactions. Six different bitter drugs were used: amlodipine besylate (AMD), diphenhydramine hydrochloride (DPH), donepezil hydrochloride (DNP), rebamipide (RBM), diclofenac sodium (DCF) and etodolac (ETD). Taste sensor outputs were significantly inhibited by the addition of CGA to all drugs. The inhibition ratio of the taste sensor output decreased in the following order DPH>DNP>AMD approximate to DCF approximate to RBM approximate to ETD. The association rate constant (k(a)) for the interaction between drugs and CGA as evaluated by SPR measurement also decreased in the following order DPH>DNP>AMD>DCF approximate to ETD approximate to RBM. It was suggested that basic drugs (AMD, DNP, DPH) associate more easily with CGA than acidic drugs (DCF, RBM, ETD). The inhibition ratios (%) of the taste sensor output of bitter drugs caused by CGA and the association rate constants (k(a)) between the drugs and CGA were significantly correlated (r(s)=0.886, p<0.05, Spearman's correlation test). Our findings suggest that the taste-masking effects of CGA are due to its direct association with the drugs. CGA may therefore be a useful taste-masking agent for basic drugs.