Bitterness Score and its Correlation to Drug Concentration: An Approach for Estimating Bitterness Suppression in a Marketed Product of Ofloxacin

Abstract

In vitro approaches for assessing taste characteristics of taste masked drug and drug products are useful in reducing reliance on human panel tests. In this study, taste panel studies were used to determine bitterness threshold and bitterness score of various solutions of ofloxacin followed by correlation and the application of this approach in estimating bitterness suppression. Bitterness scores for different solutions of ofloxacin were estimated by trained human volunteers of a taste panel. Bitterness scores were correlated to ofloxacin concentration followed by determination of bitterness scores for various dissolution samples obtained from in vitro drug release study of ofloxacin taste masked drug product. Concentration of 80 µg/ml and below was perceived bitterless by all the volunteers of taste panel. A third order polynomial equation (y=13.51x3-91.08x2+206.7x-156.6; R2 = 0.973) was derived as a relationship between bitterness score (y) and log ofloxacin concentration (x). Marketed taste masked product achieved concentrations below bitterness threshold in in vitro drug release studies performed in pharmacopoeial apparatus at initial time points (0-5 min). Bitterness threshold and bitterness scores are helpful in estimating bitterness of ofloxacin solutions provided suitable correlation has been found between them. The suggested approach, which is applicable to any bitter or objectionable tasting drug, has potential to be used as analytical tool in formulation development and quality control.