What is the primary function of suspending agents in suspensions?

• A. Increases viscosity of the dispersion medium to avoid rapid settling
• B. Improves taste
• C. Increases solubility
• D. Acts as preservative

Answer: (A)

Suspending agents are used to raise the viscosity of the liquid medium, which slows the settling of solid particles in a suspension. According to the physics of particle settling, increasing the liquid’s viscosity decreases the sedimentation rate, helping keep the dispersed particles in suspension longer and making it easier to re-disperse them after shaking. Some suspending agents also form a weak network that traps particles, providing additional physical stability and desirable flow behavior (like thixotropy) for rescinding stability during storage and dosing. Other functions like taste masking, increasing solubility, or acting as preservatives do not address how quickly particles settle, so they are not the primary role of suspending agents.