Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev

11 PROCESS-SCALE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR MEDICINAL AND AROMATIC PLANTS
11.2.5 Advantages of HPLC
The use of HPLC in the isolation and purifi cation of complex
compounds is increasing tremendously due to its fl exibility and effi ciency. It
has several advantages over traditional methods of isolation and purifi cation:
i) Variety of separating techniques.
ii) Variety of column packings for different techniques.
iii) Separation optimized by alteration of the mobile phase.
iv) Mobile phase easily manipulated in gradient systems.
v) RP technique separates very similar and very different com-
pounds simultaneously.
vi) HPLC can be used as a preparative method.
vii) HPCL can be used as a purifi cation technique. More than
one detector can be connected in series (e.g. UV and evaporative
light scattering detector).
viii) Most sample analysis is carried out at room temperature.
ix) Short analysis runs. More than 70% of HPLC separations
are performed on UV detectors and 15% rely on fl uorescence
without any derivatization.
11.3 Preparative HPLC
Preparative chromatography is the most powerful and versatile
method for isolation as well as purifi cation of complex compounds used in
drug development studies. Prior to performing preparative HPLC, the following
points must be taken into account to optimize the separation and
maximize the sample load on a small column:
• Prior to pilot-plant scale, a systematic method for development
is required
• Validated robust analytical methods are required
• Scale-up of parameters from analytical method to prep-
HPLC
• In prep-HPLC, buffer is not used
• Stationary phase with large particle sizes to decrease costs
for prep-HPLC
11.3.1 Strategy for Preparative Separation
Selection of the appropriate mode of chromatography is followed
by the optimization of the separation, i.e. stationary phase, mobile
phase, temperature, additives. The next step is optimization of the throughput,
i.e. sample amount and column overloading. In the fi nal step, stepwise
scale-up of separation is performed to obtain the desired compound.
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