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In the field of pharmaceutical formulation, optimizing the medication experience for patients is of growing interest. Besides therapeutic efficacy, factors such as taste, appearance, and convenience also play an important role in patient compliance.
A common issue is that many medicinal active ingredients, especially those of natural origin or complex chemical compounds, often have an unpleasant bitter taste. This bitterness not only makes taking medication difficult but can also cause nausea and vomiting, especially in children and the elderly, thereby negatively affecting treatment efficacy.
Increases patient treatment compliance
The bitterness of pharmaceutical active ingredients is mainly related to their chemical structure, particularly the presence of polar functional groups such as amines (-NH₂), hydroxyls (-OH), ketones (-C=O), esters (-COO-), carboxyls (-COOH), lactams (-CO-NH-), and nitrogen-containing heterocyclic systems. Active ingredients that typically require taste masking are presented in the following table:
Active Ingredient Class | Active Ingredients |
|---|---|
| Antibiotics | Erythromycin, Clarithromycin, Azithromycin, Roxithromycin, Levofloxacin, and Ciprofloxacin |
| Antivirals | Oseltamivir, Zidovudine, Lamivudine |
| Analgesics, antipyretics | Paracetamol, Ibuprofen |
| Cardiovascular | Diltiazem, Propranolol |
| Antihistamines | Fexofenadine, Diphenhydramine, Cetirizine, Loratadine |
| Anti-ulcer | Ranitidine, Famotidine |
| Anti-amoebic | Metronidazole, Secnidazole |
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Taste Masking Method | Mechanism of Taste Masking | Excipients Used |
|---|---|---|
| Sweeteners and flavorings | Reduces the perception of bitterness with sweet tastes and aromas | Sweetening agents: Sucrose, fructose, sorbitol, mannitol, xylitol, maltose, sucralose, aspartame, acesulfame K, saccharin sodium, stevia, trehalose. Flavoring agents. |
| Taste-masking film coating | Creates a barrier preventing the active ingredient from contacting saliva, while dissolving in the stomach | Ethyl cellulose, methacrylate copolymer, cellulose acetate, HPMC, PVA, shellac |
| Microencapsulation | Fully or partially encloses the active ingredient with a protective polymer layer | Ethyl cellulose, gelatin, alginate, chitosan, PVA, PLGA, HPMC |
| Cyclodextrin complexation | The active ingredient is trapped within the cyclodextrin cavity, reducing the amount of free active ingredient contacting taste receptors | β-Cyclodextrin, HP-β-cyclodextrin, SBE-β-cyclodextrin, α-cyclodextrin |
| Ion exchange resin complexation | The active ingredient exchanges ions with the excipient, not releasing in saliva but releasing in gastric fluid | Ion exchange resin excipients |
| Reducing solubility in saliva by forming salts or ester derivatives | Reduces the amount of dissolved active ingredient in the oral cavity | No excipients used, changes the chemical form of the active ingredient |
| Coating with lipid excipients via melt processes | Hydrophobic lipid layer restricts the dissolution of the active ingredient in saliva | Glyceryl dibehenate, glyceryl monostearate, carnauba wax, beeswax, stearic acid |
| Adsorption onto solid carriers | Reduces the amount of free active ingredient contacting taste receptors | Colloidal silicon dioxide, bentonite, kaolin, magnesium silicate, calcium silicate |
| Controlling active ingredient dissolution | Maintains the active ingredient as insoluble particles during its residence time in the mouth | Xanthan gum, CMC-Na, HPMC, MCC/CMC, carbomer, sodium alginate |
| Nano systems/Polymer nanoparticles | The active ingredient is entrapped within a nano-carrier system, restricting direct contact with taste buds | PLGA, chitosan, alginate, PVA, poloxamer, solid lipid excipients |
