Use of an artificial taste sensor in the evaluation of taste masking and sustained-release characteristics of trimebutine formulations

Abstract

The purpose of the present study was to evaluate the taste-masking and sustained-release characteristics of trimebutine formulations using an artificial taste sensor. Ten registered pharmaceutical drugs (amitriptyline hydrochloride, calcium pantothenate, d-chlorpheniramine maleate, dextromethorphan hydrobromide, dibucaine hydrochloride, diltiazem hydrochloride, imipramine hydrochloride, promethazine hydrochloride, trimebutine maleate and quinine hydrochloride) were used in the first part of the study. An attempt was made to predict the bitterness of these drugs on the basis of two physicochemical properties (molecular weight and logarithm of the water-octanol partition coefficient), and on the basis of taste sensor evaluation, and to compare the results with the outcome of gustatory testing by human volunteers (n = 11). The taste sensor was shown to be capable of predicting the bitterness intensities of the various drugs, but the bitterness could not be predicted on the basis of the physicochemical properties selected. Six trimebutine-loaded formulations were prepared, containing polyvinylacetal diethylaminoacetate (AEA), an acid-soluble polymer whose role was to delay release of the active ingredient and thus mask its bitter taste. Two preparation methods were used, a solvent evaporation process (four formulations) and spray drying (two formulations). The bitterness of these formulations were evaluated by human gustatory testing and by the taste sensor. The taste sensor was successful in predicting the release % of trimebutine from AEA microspheres at pH 6.8. The sensor was also able to predict the bitterness of formulations which had been suspended in water for 1, 10 and 30 min.