Sensitive and Rapid LCMS/MS Method for the Estimation of recently approved Antiviral drugs Maribavir and Fostemsavir in spiked human plasma

Abstract

In this study, a straightforward, highly sensitive, and selective liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was developed and rigorously validated for the simultaneous quantification of Maribavir and Fostemsavir in human plasma. To ensure precision and reliability, we employed Dolutegravir as the internal standard (IS). The analytical process involved a two-step extraction method. Initially, protein precipitation was induced by the addition of acetonitrile, followed by liquid–liquid extraction using a 1:1 (v/v) mixture of diethyl ether and dichloromethane as the extracting solvent. Separation of the analytes was achieved through reversed phase high-performance liquid chromatography (HPLC) using a Phenomenex C18 Luna column (4.6 mm×100 mm, 5 µm). A simple isocratic mobile phase consisting of acetonitrile, methanol, and 0.1% formic acid (35:55:10, v/v) was used, operating at a flow rate of 0.5 mL/min. Under these optimized conditions, the LC chromatogram of the spiked standard exhibited distinct peaks at retention times of 2.07 min, 2.59 min, and 4.29 min for Fostemsavir, Maribavir, and the internal standard, respectively. Detection was performed using a triple quadrupole mass spectrometer employing electrospray ionization in positive ion mode and multiple reaction monitoring (MRM) mode. The mass transitions monitored were m/z 377 → 110, m/z 584 → 105, and m/z 420 → 142 for maribavir, fostemsavir, and dolutegravir, respectively. This method provided a rapid analysis within 5 minutes, over a linear concentration range of 15-750 ng/mL for both maribavir and fostemsavir. Method validation was conducted following FDA guidelines for bio-analytical methods, and the results consistently fell within the acceptable limits for both analytes. Therefore, our developed method holds promise for the accurate analysis of maribavir and fostemsavir in human plasma, and it has potential applications in pharmacokinetic studies