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HPLC Application Sheet
Pharmaceutical Preparation: General Method Using a Gradient in Classic Normal Phase Mode
Note: Cogent Bidentate C18™ columns can be changed from Reverse Phase Mode to Classic Normal Phase – HPLC (and vice
versa) using easy 30 minutes procedure:
A – To convert from Reverse Phase mode to Normal Phase mode on these columns, pump 100% methanol through the column for 15
minutes at 1 mL/min. Follow with 100% methylene chloride for 15 minutes. The column is ready to be equilibrated with
your mobile phase for normal phase chromatography.
B – To convert from Normal Phase mode to Reverse Phase Mode on these columns, pump 100% methylene chloride for 15 minutes
at 1 mL/min. Follow with 100% methanol for 15 minutes. The column is now ready to be equilibrated with your mobile phase
for reverse phase mode chromatography.
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printable Application Sheet
Carvone: Recently the USA National Cancer Institute and others are evaluating chemo-preventive and anti-carcinogenic
properties of monoterpenes (naturally occurring non-nutrient dietary constitutes like Carvone). If administrated in the
diet, they prevent or cause the regression of colon, hepatic and pancreatic cancers chemically induced in laboratory
animals. Loratadine: (Lora) is a non-sedative second generation H1 receptor blocker. It is available commercially as mono
component tablets (Claritin1).
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Method Conditions
| Column |
Cogent Bidentate C18, 4µm, 100A |
| Catalog No. |
40018-75P |
| Dimensions |
4.6 x 75mm |
| Gradient |
0 – 0.5 min 100% hexane
0.5 – 7.0 min 50% hexane
+ 50 % dichloromethane
7.0 – 10.0 min 50% hexane
+ 50 % dichloromethane
10 - 10.5 min 100% hexane |
| Flow rate |
0.5 mL/minute |
| Injection Volume |
10 µL |
| Peaks |
1. Carvone
2. Loratadine
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| Concentration |
0.1 mg/mL in Hexane/DCM(1:1) |
| Detection |
UV at 254 nm |
Discussion
Both Carvone and Loratadine have similar polarity but they can be separated using Cogent Bidentate C18™ column with
significant retention (k>2). When the mobile phase of 95% hexane and 5% dichloromethane is used the Loratadine is
infinitely retained. The classic Normal Phase analysis shown above is simple, rapid and cost effective and can be used in
routine quality control in the production or purity determination of both Carvone and/or Loratadine. The proposed method
can be used as a general method for analysis of pharmaceutical compositions for oral administration containing an
antihistaminic compound and a terpenoid compound, which are useful in the prevention or treatment of inter alia allergic
rhinitis (hay fever) and mild asthma.
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