Extraction Technologies For Medicinal And Aromatic Plants - Unido

3.6.3.1.2 Offi cial Extractor
EXTRACTION TECHNOLOGIES FOR MEDICINAL AND AROMATIC PLANTS
An offi cial extractor, as described in the offi cial monographs
(e.g. IP, British Pharmacopoeia), is illustrated in Figure 5. In this case, the
extraction is a continuous percolation procedure. In this apparatus, vapors
rise through the extraction chamber passing the drug container; the vapor
condenses in the refl ux condenser and returns through the drug, taking the
soluble constituents to the fl ask.
Figure 5: Apparatus for the continuous extraction of drugs
3.6.3.2 Limitations of the Offi cial Extractor
It is not useful when the raw material contains thermolabile
active constituents, because the extraction is carried out at an elevated
temperature and the extract in the fl ask is also maintained in the hot condition
until the process is complete. It can be used only with pure solvents
or with solvent mixtures forming azeotropes. If an ordinary binary mixture is
used as the menstruum, the composition of the vapor will be different from
the liquid composition.
Similar methods can be used in large-scale production.
A typical industrial set-up for continuous extraction is shown in
Figure 6. The principle of operation resembles that of the laboratory equipment.
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