Which method of extraction involves the solvent passing through the drug source via a column (percolator)?

• A. Maceration
• B. Percolation
• C. Infusion
• D. Extraction

Answer: (B)

Percolation is the flow-through extraction process, where the solvent is directed to pass through a column packed with the drug material (in a device called a percolator). As the solvent moves through the column, it continually contacts fresh surfaces of the material, dissolving soluble constituents and carrying them out as the percolate. This setup makes the extraction more efficient and controlled, yielding a uniform extract compared with methods that don’t involve a flowing solvent through a column.

Maceration, by contrast, simply soaks the material in solvent without forcing flow through a column; infusion uses hot water to steep the material; and extraction is a general term that doesn’t specify the column-flow arrangement.