El-Naem, Omnia ASaleh, Sarah S2021-04-112021-04-1104/02/2021https://doi.org/10.1016/j.microc.2021.106234https://qrgo.page.link/YKnVdFacing the pandemic COVID-19 is of highest priority for all researchers nowadays. Recent statistics indicate that the majority of the cases are home-treated. Two drugs of interest, Guaifenesin and Bromohexine HCl, are among the add-on therapy for treatment of COVID-19 mild cases, which has raised the need for their simultaneous determination. The analysis of the two drugs of interest was described using ultra-performance liquid chromatography–tandem mass spectrometric (UPLC–MS/MS) in plasma of healthy human volunteers using tetryzoline HCl as an internal standard (IS) after liquid-liquid extraction. The applied chromatographic conditions were Kinetex C18 (100Å, 2.6 µm X 50 mm X 4.6 mm) column and a mixture of methanol: water (95: 5, v/v) as a mobile phase at flow rate 1 mL/min. The positive ionization mode was used for detecting the ions, by observing the pairs of transition m/z 199< 125 for GUF, m/z 377< 114 for BRM and m/z 201 <131 for IS. The linearity range was from 50-1500 ng/mL for GUF and 0.5-50 µg/mL for BRM. Limit of detection (LOD) was found to be 35.16 and 0.43 ng/ml for GUF and BRM, respectively. The method was validated according to FDA guidance. The proposed method was assessed to be more eco-friendly versus the reported method using the greenness assessment tools: National Environmental Methods Index (NEMI), Assessment of Green Profile (AGP), Green Analytical Procedure Index (GAPI) and Eco-Scale. The proposed method was applied for the application of a pilot pharmacokinetic study.en-USEco-scaleGuaifenesinBromhexineGAPIpharmacokineticArticlehttps://doi.org/10.1016/j.microc.2021.106234