An automated method for the determination of montelukast in human plasma using dual-column HPLC analysis and peak height summation of the parent compound and its photodegradation product.

Purpose: To develop an assay to evaluate the bioequivalence of overcoated and marketed montelukast formulations, the former to be used for future blinded clinical studies.

Methods: The method used automated 96-well sample preparation and dual-column HPLC analysis for increased throughput. Regression analysis was performed using the total peak height of montelukast and its photodegradent, a cis-ethenyl geometric isomer.