Aim:The current investigation was focused on the development and validation of a simple, accurate, and rugged RP-HPLC method for the simultaneous estimation of Formoterol fumarate and Tiotropium bromide in mixed pharmaceutical dosage forms. Methodology:The technique employed a Waters HPLC system with UV detection at 240 nm (the isobestic point). Chromatographic separation was on a C18 column under isocratic mobile phase consisting of phosphate buffer (pH 3.0) and acetonitrile in the ratio of 65:35 v/v at a flow rate of 2.0 mL/min. Standard and sample solutions were made from DUOVA Rotacaps. The procedure was tested for specificity, linearity, accuracy, precision, repeatability, robustness, ruggedness, and system suitability as per ICH Q2(R1) guidelines. Results:Formoterol and Tiotropium eluted at about 3.3 and 5.7 minutes, respectively. The technique showed good linearity with R² = 0.9995 for Formoterol. Recovery studies established high accuracy (98–102%), and intra- and inter-day precision was <%RSD 2%. Robustness and ruggedness tests identified the stability of the method under minimal changes in the analytical conditions. Conclusion:The validated procedure is precise, accurate, specific, and appropriate for routine quality control of fixed-dose bronchodilator combinations. Its short run time, simplicity, and reproduciability make it a perfect choice for industrial and regulatory use
Bhusari et al. (Tue,) studied this question.