Development and Validation of a Simple, Selective, and Sensitive LC-MS/MS Assay for the Quantification of Remdesivir in Human Plasma

Abstract Remdesivir, formerly GS-5734, has recently become the first antiviral drug approved by the U.S. Food and Drug Administration (FDA) to treat COVID-19, the disease caused by SARS-CoV-2. Therapeutic dosing and pharmacokinetic studies require a simple, sensitive, and selective validated assay to quantify drug concentrations in clinical samples. Therefore, we developed a rapid and sensitive LC-MS/MS assay for the quantification of remdesivir in human plasma with its deuterium-labeled analog, remdesivir-2H5, as the internal standard. Chromatographic separation was achieved on a Phenomenex® SynergiTM HPLC Fusion-RP (100 x 2 mm, 4 μm) column by gradient elution. Excellent accuracy and precision (