Which of the following is NOT an ingredient typically listed in a suspension formulation?

• A. Active ingredient
• B. Distilled water
• C. Wetting agents
• D. Flavorings

Answer: (B)

In a suspension, the important components are the active drug plus additives that keep the solid particles dispersed and the formulation palatable. The active ingredient is clearly listed because it determines the dose. Wetting agents are included to reduce surface tension and help the drug particles take up the liquid, enabling proper dispersion, so they appear on the label. Flavorings (and sweeteners) are used to improve taste and are also listed. The water is the medium that carries everything—it's the solvent for the suspension. Often, the vehicle is treated as the base rather than an active additive, so it isn’t listed the same way as the functional excipients. Therefore, distilled water is not typically listed as a separate ingredient like the others.