Enantiomeric separation of vilanterol trifenatate by chiral liquid chromatography

: Vilanterol trifenatate is a novel chiral long-acting β2-agonist developed. Vilanterol combined with inhaled corticosteroids can treat COPD and asthma. A simple liquid chromatographic method is developed for the quantitative determination of R-vilanterol and S-vilanterol (impurity S). HPLC separation was achieved on Chiralpak ID (250 × 4.6 mm; particle size 5 μm) column using hexane-ethanol-ethanolamine (75:25:0.1, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The resolution is greater than 3.3. Ethanolamine in the mobile phase is vital to enhance chromatographic efficiency and resolution between the isomers. The method was validated with respect to accuracy, specificity, precision, LOD, LOQ, linearity, and robustness as ICH guidelines.