CMC or acacia can be used in suspensions for external use.

• A. True
• B. False
• C. Only CMC
• D. Only Acacia

Answer: (B)

Suspending agents are chosen based on the route of administration and the overall formulation needs to keep particles evenly dispersed without irritating the site of administration. While carboxymethylcellulose (CMC) and acacia gum can act as suspending agents, they are not universally suitable for suspensions intended for external use. External-use formulations, such as topical suspensions, require rheology, stability, and skin compatibility that aren’t guaranteed by these two agents in all cases. Acacia gum can be very sticky and may cause allergenicity or microbial growth in aqueous systems, and CMC’s performance depends on pH and ionic conditions; other agents (such as carbomers, clays, or specific cellulose derivatives) are often preferred for dermal applications. So the statement is not universally true.