Multiplexed therapeutic drug monitoring (TDM) of antiviral drugs by LC–MS/MS

Background: Therapeutic drug monitoring (TDM) can be a useful tool in the clinical management of anti-hepatitis C virus (anti-HCV) drugs. Methods for the determination of various types of anti-HCV drugs in biological samples are, therefore, needed for clinical laboratories. Objective: In this work, employing the LC–MS/MS approach, we aimed to develop a multiplexed method for identification of the following anti-HCV drugs: Ribavirin (RBV), Boceprevir (BOC), Telaprevir (TVR), Simeprevir (SIM), Daclatasvir (DAC), Sofosbuvir (SOF) and its metabolite GS 331007 (SOFM) in liquid plasma and in dried plasma spots (DPSs). Method: A single-step extractive-deproteinization was employed for both liquid plasma and DPSs. Reverse-phase liquid chromatography coupled with MRM detection was developed for multiplexed drug detection and quantification. Results: Sensitivities (expressed as LOQ) were 10 ( ± 1.2), 10 ( ± 4.9), 10 ( ± 4.4), 10 ( ± 4.4), 10 ( ± 6.4), 10 ( ± 3.4), 10 ( ± 6.4) ng/ml for RBV, SOFM, SOF, DAC, BOC, TVR, and SIM, respectively; accuracy (expressed as BIAS%) was < 10% for all drugs; reproducibility (intra- and inter-day CV%) was < 10% for all drugs; dynamic range was 10–10,000 ng/ml for all drugs. Conclusions: A novel, simple, rapid and robust LC–MS/MS multiplex assay for the TDM of various anti-HCV drugs that are currently in the clinic was successfully developed. Application to DPS samples enabled TDM to be used for outpatients as well.