The document discusses the advantages of using Agilent ZORBAX Rx-SIL reversed-phase HPLC column for the separation of amines, particularly in the analysis of cough syrups. By using a reversed-phase mobile phase, the excessive retention and poor peak shape caused by the interaction of amines with unbonded silanols can be overcome. The Rx-SIL particles are stronger and more resistant to dissolution compared to xerogel silicas. This method provides the desired separation for the compounds commonly associated with cough syrups.
Organic amines in pharmaceutical formulations, such as those found in cough syrups, often present analytical challenges due to excessive retention and poor peak shape on standard reversed-phase columns caused by silanol interactions. This document presents a method that utilizes these interactions advantageously to achieve effective separation of common active ingredients.
The proposed method employs an Agilent ZORBAX Rx-SIL column with a specific mobile phase consisting of methanol and potassium dihydrogen phosphate at pH 7. The text details the chromatographic conditions, including flow rate, temperature, and detection wavelength, demonstrating successful separation of compounds like guaifenesin, phenylpropanolamine, brompheniramine, pseudoephedrine, and dextromethorphan.
The analysis uses a ZORBAX Rx-SIL column with dimensions of 4.6 x 150mm.
The mobile phase should be flowed at a rate of 2mL/ min.
The column must be flushed with a miscible solvent such as THF before equilibrating with the aqueous mobile phase.