pharmaceutical taste masking

Pharmaceutical bitterness masking encompasses dosage-form design methods to soften the taste of an active ingredient that is difficult to take. One review divides the mechanisms into 2 broad groups. One uses flavors or bitterness-suppressing additives to compete with the drug and interfere with taste transmission to tongue receptor cells. The other prevents the unpleasant-tasting drug from dissolving in the mouth, through approaches including ion-exchange resins, solid dispersions, polymer coatings, prodrugs, microcapsules, liposomes, nanoemulsions, and cyclodextrin inclusion.

A European medicines regulator's guideline for developing pediatric medicines lists more practical choices: selecting excipients such as bitterness maskers, sweeteners, and flavors; changing particle size of the active ingredient or excipients; changing the active ingredient's salt form; coating the active ingredient or final dosage form; using inclusion agents such as cyclodextrins; and, for liquids, reducing the amount of active ingredient dissolved in solution. Neither this guideline nor the review gives data comparing the size of effects across these methods.

A decoction containing Platycodon for children gives a concrete example of these methods. Adding hydroxypropyl-β-cyclodextrin at 6.5% relative to the Platycodon root and xylitol at 10% changed its rating from 「受け入れがたい」 (in translation: "difficult to accept") to 「後に苦味の残らない甘さ」 (in translation: "sweet with no lingering bitterness"); electronic-tongue measurements also supported the change. Cyclodextrin was described as suppressing lingering bitterness and astringency, while xylitol improved mouthfeel, but this result was confirmed for 2 formulations.

A prior study cited by the review presents a commercial dry-syrup formulation of clarithromycin, known for pronounced bitterness, made with a physical coating. Compared with a powder suspension at the same concentration, sensory bitterness intensity was estimated to fall to about 1%. Both human sensory assessment and prediction by a taste sensor supported this masking.

Another prior study cited by the same review reports pediatric quinine-sulfate pellets prepared by extrusion-spheronization and given an Eudragit EPO bitterness-masking coating at 10%, 20%, or 30%. As coating concentration increased, dissolution during the first 5 minutes fell to 9.2%, 5.9%, and 2.1%, respectively. This trend corresponded to lower bitterness scores from an Astree taste-sensor system. The prior study judged a 20% coating optimal for forming a uniform film while suppressing bitterness sufficiently.