Amphiphilic Block Copolymers: A Novel Substance for Bitter-Masking in Aqueous Solutions.

It is a challenging task to suppress the bitterness of liquid preparations, especially for children. Bitter molecules are highly dispersed in the liquid, leading to a strong and instant stimulation of the bitter receptors. At present, there is no effective way to correct this issue except for adding sweeteners, resulting in an unsatisfying taste. Based on the three-point contact theory, which is a universally accepted mechanism of bitterness formation, a new idea and application of amphiphilic block copolymers (ABCs) for bitterness suppression was proposed for the first time. We found that ABCs could widely inhibit the bitterness of four typical bitter substances. The mechanism was that ABCs self-assembled to form association colloids, which attracted bitter components and reduced their distribution in molecular form in solution. The bitter components were demonstrated to automatically embed in the spiral hydrophobic cavity of the hydrophobic chain of the ABC, and their special interaction dispersed the positive electrostatic potential of bitter groups. The combination did not affect the pharmacokinetic parameters and pharmacodynamics of the bitter drugs. These findings highlight the novel application of ABCs for the inhibition of bitterness and illuminate the underlying inhibition mechanisms.