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Abstract
Since the last decade, there is enhanced interest for
extraction of the constituents from plants and animal
origin. The traditional techniques like maceration,
percolation, decoction and some existing methods such as
Soxhelation, Super Critical fluid Extraction, etc., are
time taking and solvent consuming. This series rings
into prominence the importance of novel method of
extraction for delivering high quality product. The
Pressurized Fluid Extraction Technique (PFE) is a
promising technique, which is highlighted by increased
extraction yield, decreased time and solvent
consumption. More over it helps for removal of solid
impurities and the reproducibility is better. A brief
theoretical background of the Principle involved,
Instrument, and Comparative efficiency with other
conventional methods of extraction, method of solid
impurities removal and its applications are presented.
Introduction
World health organization currently encourages,
recommends and promotes traditional/herbal remedies in
national health care programmes because such drugs are
low cost, are comparatively safe and the people have
faith in such remedies1. As our understanding of
chemistry and other natural sciences has increased, the
active chemical compounds of the plants have been
successfully isolated and identified.2 Extraction of
crude drugs can be done by various processes depending
on the physical nature of the drug and chemical
properties of the constituents present in it. The demand
for new extraction techniques has encouraged the
development of alternative extraction techniques such as
ultra sonic assisted extraction, super critical fluid
extraction and pressurized fluid extraction. These
techniques have enabled automation, shortened time and
reduced organic solvent consumption.3 Pressurized fluid
extraction (PFE) is similar to Soxhelet extraction,
except that the solvents are used near their
supercritical region where they have high extraction
properties. In that physical region the high temperature
enables high solubility and high diffusion rate of lipid
solutes in the solvent, while the high pressure, in
keeping the solvent below its boiling point, enables a
high penetration of the solvent in the sample. Thus, PFE
permits high extraction efficiency with a low solvent
volume (15-40 ml) and a short extraction time (15-20
min). That procedure is also known as “Accelerated
Solvent Extraction” (ASE). This procedure was first
developed by Dionex4 and validated on a commercially
available, automated extraction system.
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