Omeprazole structural formula

CAS Number73590-58-6
Molecular FormulaC17H19N3O3S
Molecular Weight345.421
  • Omeprazole
  • 5-Methoxy-2-[(4-methoxy-3,5-dimethylpyridin-2-yl)methanesulfinyl]-1H-benzimidazole
  • 1H-Benzimidazole, 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-
  • 73590-58-6
  • Equiprazole, Epirazole
  • 1H-Benzimidazole, 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-
  • (.+-.)-Omeprazole
  • 1H-Benzimidazole, 6-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-
  • 2-[[(3,5-Dimethyl-4-methoxy-2-pyridyl)methyl]sulfinyl]-5-methoxy-1H-benzimidazole
  • 5-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole
  • 5-Methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]sulfinyl]-1H-benzimidazole
  • Antra MUPS
  • Audazol
  • Belmazol
  • Ceprandal
  • Dizprazol
  • Dudencer
  • Emeproton
  • Epirazole
  • Gastrimut
  • GastroGard
  • Gastroloc
  • Gastrozole
  • Gibancer
  • Indurgan
  • Inhibitron
  • Inhipump
  • Logastric
  • Megazole
  • Miracid
  • Omapren
  • Omepradex
  • Omepral
  • Omeprazen
  • Omeprazole-Towa
  • Omeprazon
  • Omepril
  • Omeprol
  • Omezzol
  • Ompanyt
  • Ovulanze
  • Parizac
  • Pepticum
  • Peptilcer
  • Prazidec
  • Prilosec
  • Ramezol
  • Roweprazol
  • Sanamidol
  • Secrepina
  • Ulceral
  • Ulcesep
  • Ulcometion
  • Ulcozol
  • 5-Methoxy-2-(((4-methoxy-3,5-dimethyl-2-pyridyl)methyl)sulfinyl)benzimidazole
  • Demeprazol
  • Erbolin
  • Morecon
  • Nopramin
  • Omegast
  • Omezolan
  • Ortanol
  • Paprazol
  • Pepticus
  • Prazentol
  • Prazolit
  • Procelac
  • Proclor
  • Regulacid
  • Tedec Ulceral
  • Victrix
  • (+-)-Omeprazole
  • 2-(((3,5-Dimethyl-4-methoxy-2-pyridyl)methyl)sulfinyl)-5-methoxy-1H-benzimidazole
  • Omeprazol
  • Omeprazolum
  • Omeprazole delayed-release
  • UNII-KG60484QX9
  • 5-methoxy-2-{[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl}-1H-benzimidazole
  • 131959-78-9
  • 172964-80-6


Determination Omeprazole on Obelisc R Column

February 11, 2021
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Omeprazole is a proton pump inhibitor, a medication that decreases the amount of acid produced in the stomach.  Omeprazole has a bactericidal effect on Helicobacter pylori.

Obelisc R column which has both positive and negative ion-pairs embedded in the stationary phase allows for fine tuning and separation of a wide range of compounds with different ionic properties.  Omeprazole was separated isocratically using a simple MS-compatible mobile phase of acetonitrile (ACN) and water with Ammonium Acetate (AmAc) buffer.  Can also be UV detected at 300nm.

Condition 1

Column Obelisc R, 4.6×150 mm, 5 µm, 100A
Mobile Phase MeCN -35%
Buffer Ammonium Acetate  pH 5.5 – 10 mM
Flow Rate 1.0 ml/min
Detection UV 300 nm

Condition 2

Column Obelisc R, 4.6×150 mm, 5 µm, 100A
Mobile Phase Gradient MeCN -20-50% in 15 min + 5 min hold
Buffer Ammonium Acetate  pH 5.5 – 10 mM
Flow Rate 1.0 ml/min
Detection UV 300 nm



Class of Compounds
Analyzing Compounds Omeprazole


Application Column

Obelisc R

SIELC has developed the Obelisc™ columns, which are mixed-mode and utilize Liquid Separation Cell technology (LiSC™). These cost-effective columns are the first of their kind to be commercially available and can replace multiple HPLC columns, including reversed-phase (RP), AQ-type reversed-phase, polar-embedded group RP columns, normal-phase, cation-exchange, anion-exchange, ion-exclusion, and HILIC (Hydrophilic Interaction Liquid Chromatography) columns. By controlling just three orthogonal method parameters - buffer concentration, buffer pH, and organic modifier concentration - users can adjust the column properties with pinpoint precision to separate complex mixtures.

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Application Analytes:
SIELC Technologies usually develops more than one method for each compound. Therefore, this particular method may not be the best available method from our portfolio for your specific application. Before you decide to implement this method in your research, please send us an email to so we can ensure you get optimal results for your compound/s of interest.

Separation of Omeprazole on Newcrom R1 HPLC column

February 16, 2018
Separation of Omeprazole on Newcrom C18 HPLC column

Omeprazole can be analyzed by this reverse phase (RP) HPLC method with simple conditions. The mobile phase contains an acetonitrile (MeCN), water, and phosphoric acid. For Mass-Spec (MS) compatible applications the phosphoric acid needs to be replaced with formic acid. Smaller 3 µm particles columns available for fast UPLC applications. This liquid chromatography method is scalable and can be used for isolation impurities in preparative separation. It also suitable for pharmacokinetics.

Application Column

Newcrom R1

The Newcrom columns are a family of reverse-phase-based columns. Newcrom A, AH, B, and BH are all mixed-mode columns with either positive or negative ion-pairing groups attached to either short (25 Å) or long (100 Å) ligand chains. Newcrom R1 is a special reverse-phase column with low silanol activity.

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Application Analytes:
The result was obtained by a proprietary SIELC algorithm. It may deviate from the actual experimental data. The experimental data are available upon request. Contact us by e-mail: or by phone: 847-229-2629.