HPLC Determination of Enantiomeric Purity of Letermovir Based on CHIRALPAK AD.

A precise and sensitive LC method was developed and further validated for the determination of enantiomeric purity of {(4S)-8-Fluoro-2-[4-(3-methoxyphenyl)-1-piperazinyl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydro-4-quinazolinyl} acetic acid (Letermovir). Baseline separation with a resolution >2.8 was accomplished within 10 min using a CHIRALPAK AD (250 mm × 4.6 mm; particle size 5 μm) column, with n-hexane/2-propanol (80:20 v/v) as mobile phase at a flow rate of 1 mL min-1. The eluted analytes were monitored by UV detection at 260 nm. The effects of mobile phase composition and temperature on enantiomeric selectivity as well as resolution of enantiomers were thoroughly investigated. The calibration curves were plotted within the concentration range between 0.003 and 1 mg mL-1 (n = 14), and the recoveries between 98.24 and 101.43% were obtained, with relative standard deviation <1.29%. The limit of detection (LOD) and limit of quantitation (LOQ) for Letermovir were 0.96 and 3.15 μg mL-1; those for its enantiomer were 1.01 and 3.39 μg mL-1, respectively. The developed method was demonstrated to be accurate, robust and sensitive for the determination of enantiomeric purity of Letermovir, especially for the analysis of bulk samples.