pharmaceutical
Applications
note
RestekCorporation • (800)356-1688 • (814)353-1300 •
#59545
pharmaceutical
HPLC Analysis of Basic Pharmaceutical
Compounds on an Ultra Cyano Phase
Figure1
HPLC Separation of Popular CalciumChannel Blockers Shows
Good Peak Shape and Resolution in 10minutes
1
2
3
4
5
min.
1
2
3
4
5
6
7
8
9
10
Peak List:
1. diltiazem
2. nifedipine impurity
3. verapamil
4. nifedipine
5. nicardipine
Column:
Ultra Cyano
Catalog Number:
9106565
Dimensions:
150 x 4.6mm
Particle Size:
5µm
Pore Size:
100Å
Conditions:
Solvent A:
20mM KH
2
PO
4
, pH 3 with H
3
PO
4
Solvent B:ACN
Mode:
Isocratic, (70:30, A:B) (v/v)
Flow Rate:
1.2mL/min
Wavelength:
235nm
Pharmaceuticals designed for use as antihypertensive agents
are challenging samples for high performance liquid
chromatography (HPLC) methods development. The
challenge arises when the basic functional group in the
sample interacts with a residual silanol group in the column
packing, causing peak tailing and difficult quantitation.
When compared to C18 phases, a bonded base-deactivated
cyanopropyl phase exhibits the best peak shape for basic
pharmaceutical compounds. However, cyano phases on
traditional Type A silica can be unstable under certain pH
conditions (Scheme 1). In order to combat these problems,
we’ve developed new deactivation and bonding chemistries
for the Ultra Cyano HPLC column, which increase phase
stability and eliminate potential hydrolysis when incorpo-
rated with a highly pure, Type B silica support. The high
bonding density (8% carbon) increases the retention/
capacity factor for analytes, resulting in better resolution of
complex mixtures.
Figure 1 illustrates the separation of calcium channel
blockers, a common analysis containing compounds with
these basic functional groups, using an Ultra Cyano HPLC
column. The 150 x 4.6mm column produces good resolution
in less than ten minutes and excellent peak symmetry
without tailing. Through changes to the deactivation,
bonding chemistry, and bonding density, Ultra Cyano HPLC
columns provide a superior chromatographic solution to
difficult pharmaceutical analyses.
