Emulsions can form aggregates of the dispersed droplets through both gravitational separation and inter-droplet interactions. If the dispersed phase is less dense than the continuous phase, droplets drift upward and collect at the top—creaming. If it is more dense, they drift downward to the bottom—sedimentation. Droplets can also cluster together without merging, a process called flocculation, where they stay as individual droplets but move together as a loose aggregate. Finally, droplets can merge to form larger droplets, known as coalescence, which directly changes the size distribution and accelerates separation. These four modes—creaming, sedimentation, flocculation, and coalescence—describe how the internal phase can form aggregates in an emulsion.

In pharmaceutical liquids, syrups are concentrated aqueous sugar solutions, while elixirs are hydro-alcoholic solutions where alcohol serves as part of the solvent. Because alcohol is a defining component of elixirs, they contain a noticeable amount of ethanol, whereas syrups contain little to no alcohol beyond trace amounts from flavorings or preservatives. Thus, elixirs have a higher proportion of alcohol than syrups, making the statement false. Some syrups may include small amounts of alcohol, but the overall alcohol content is still much higher in elixirs.

Elixirs are clear, sweetened, flavored hydroalcoholic solutions intended for oral use. This form dissolves drugs in a hydroalcoholic solvent and includes sugar and flavoring to make the medicine pleasant to take, which is why it’s described exactly this way. The other forms don’t fit because tinctures are alcoholic extracts that are typically bitter and not prepared to be palatable; suspensions are liquids with dispersed solid particles and may be opaque or require shaking; emulsions are mixtures of immiscible liquids that are not single-phase solutions. Syrups are aqueous sugar solutions with no alcohol, so they aren’t hydroalcoholic.

When using the fusion method, you melt the base to create a uniform liquid so all ingredients can mix evenly. Heat-labile components are sensitive to high temperatures, so they should not be exposed to the molten mixture for long. Adding them after you remove the heat (or after the base has cooled to a safe temperature) protects them from degradation, volatilization, or loss of potency and helps ensure they’re distributed properly in the final product. If they were added while the base was still molten, their stability could be compromised and the final formulation might have clumping or uneven dosing. So the statement is true: heat-labile components should be added last when using the fusion method.