Extractables are the things pulled out or carried away by a solvent. Soak or contact a sample with a solvent over time, and the dissolved matter that appears in the solvent is the extractables.
Think of brewing tea: substances from the leaves dissolve into hot water, those dissolved components are the extractables. Industrially it controls herbal potency, packaging migration and waste toxicity.
Determination (herbal example)
1) Extract the sample by heating under reflux with a specified solvent (water/ethanol). 2) Filter and make up volume. 3) Take an aliquot and evaporate to dryness (constant weight at 105 °C) or dry. 4) Weigh and calculate extractables content (%).
Relation to extractables/leachables
Extractables (forced solvent extraction) and leachables (migration under real use) are packaging or device sub-terms; the broad extractables covers both, and the ERT-C can evaporate and weigh their residue.
