Which statement best describes the proper role of a suspending agent in suspension formulations?

• A. It is added to thicken (increase viscosity) the dispersion medium to avoid rapid settling
• B. It is added to neutralize odor
• C. It is added to color the suspension
• D. It is added to decrease drug stability

Answer: (A)

The effect being tested is that suspending agents slow the settling of solid particles by increasing the viscosity (or forming a loose gel) in the dispersion medium. By making the liquid thicker or creating a network, the sedimentation rate falls according to Stoke’s law, helping keep particles dispersed longer and making redispersion easier after storage or before use. This improves physical stability and dosing uniformity. The other ideas—neutralizing odor, coloring the suspension, or intentionally decreasing drug stability—aren’t the role of a suspending agent; they’re achieved by other additives and would not enhance the suspension’s ability to stay uniformly dispersed.