Three factors must be considered when selecting a syrup. Which set lists these factors?

• A. Flavor, color, and odor
• B. Drug stability, viscosity, and odor
• C. Solubility, pharmacokinetics, and regulatory status
• D. Drug solubility, drug stability, and drug compatibility

Answer: (D)

When choosing a syrup as a vehicle for a drug, you must ensure the drug will behave properly in that medium: it needs to dissolve or be evenly dispersed, stay stable during storage and use, and remain compatible with all syrup components. Solubility is crucial because if the drug isn’t soluble or well-dispersed at the intended dose, you won’t achieve accurate dosing or consistent bioavailability. Stability is essential because the syrup environment—high sugar content, possible pH, and additives like preservatives—can promote chemical or physical degradation; a stable drug will retain potency over the product’s shelf life. Compatibility matters because interactions with flavors, colorants, preservatives, or other excipients can cause precipitation, color or odor changes, or altered potency, undermining safety and efficacy. While taste or appearance and even regulatory considerations can influence formulation choices, they do not address the core requirements for delivering the drug reliably in a syrup. Therefore, the set that lists drug solubility, drug stability, and drug compatibility best captures the key factors.