______ is the extraction method where the drug is extracted by the slow passage of a suitable solvent through a column (percolator) with the drug source

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

Answer: (C)

Percolation is the extraction method where a suitable solvent is passed slowly through a column (percolator) packed with the drug source. As the solvent trickles through, it dissolves the soluble constituents and carries them out as the extract. The slow, controlled flow keeps contact between solvent and material optimized, which helps recover heat-sensitive compounds without overheating. This differs from maceration, which involves soaking the material in solvent without a column, and from filtration, which is a separation step rather than an extraction method. General extraction is too broad and doesn’t specify the column-and-flow process.