Analysis of Dextromethorphan-Based Drug composition. Effect on buffer pH

Dextromethorphan is one of the common cough suppressants used in many drug composition. It is in tablets and syrups as an antitussive drug. Composition often has preservatives like parabens. Dextromethorphan is a hydrophobic, basic drug which is used as a bromide salt in drug compositions. Dextromethorphan and two parabens (methyl paraben and propyl paraben) were separated on Primesep C reversed-phase cation-exchange column. Several impurities were observed and are well separated from the main components of the drug composition. Method can be used for various formulations in QC and production environment.



Column Primesep C, 4.6×150 mm, 5 µm, 100A
Mobile Phase MeCN/H2O – 35/65%
Buffer TEAPh
Flow Rate 1.0 ml/min
Detection UV, 210 nm



Class of Compounds
Drug, Preservatives,  Base, Hydrophobic, Ionizable
Analyzing Compounds Dextromethorphan, Bromide, Methyl Paraben, Propyl Paraben


Application Column

Primesep C

The Primesep family of mixed-mode columns offers a wide variety of stationary phases, boasting unprecedented selectivity in the separation of a broad array of chemical compounds across multiple applications. Corresponding Primesep guard columns, available with all stationary phases, do not require holders. SIELC provides a method development service available to all customers. Inquire about our specially-tailored custom LC-phases for specific separations.

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Application Analytes:

Application Detection:
UV Detection
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.