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Biomed Chromatogr ; 36(6): e5365, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1739127


Favipiravir is a potential antiviral medication that has been recently licensed for Covid-19 treatment. In this work, a gadolinium-based magnetic ionic liquid was prepared and used as an extractant in dispersive liquid-liquid microextraction (DLLME) of favipiravir in human plasma. The high enriching ability of DLLME allowed the determination of favipiravir in real samples using HPLC/UV with sufficient sensitivity. The effects of several variables on extraction efficiency were investigated, including type of extractant, amount of extractant, type of disperser and disperser volume. The maximum enrichment was attained using 50 mg of the Gd-magnetic ionic liquid (MIL) and 150 µl of tetrahydrofuran. The Gd-based MIL could form a supramolecular assembly in the presence of tetrahydrofuran, which enhanced the extraction efficiency of favipiravir. The developed method was validated according to US Food and Drug Administration bioanalytical method validation guidelines. The coefficient of determination was 0.9999, for a linear concentration range of 25 to 1.0 × 105  ng/ml. The percentage recovery (accuracy) varied from 99.83 to 104.2%, with RSD values (precision) ranging from 4.07 to 11.84%. The total extraction time was about 12 min and the HPLC analysis time was 5 min. The method was simple, selective and sensitive for the determination of favipiravir in real human plasma.

COVID-19 , Ionic Liquids , Liquid Phase Microextraction , Amides , COVID-19/drug therapy , Chromatography, High Pressure Liquid/methods , Furans , Gadolinium , Humans , Liquid Phase Microextraction/methods , Magnetic Phenomena , Pyrazines
J Chromatogr B Analyt Technol Biomed Life Sci ; 1189: 123087, 2022 Jan 15.
Article in English | MEDLINE | ID: covidwho-1587335


Favipiravir is a promising antiviral agent that has been recently approved for treatment of COVID-19 infection. In this study, a menthol-assisted homogenous liquid-liquid microextraction method has been developed for favipiravir determination in human plasma using HPLC/UV. The different factors that could affect the extraction efficiency were studied, including extractant type, extractant volume, menthol amount and vortex time. The optimum extraction efficiency was achieved using 300 µL of tetrahydrofuran, 30 mg of menthol and vortexing for 1 min before centrifuging the sample for 5 min at 3467g. Addition of menthol does not only induce phase separation, but also helps to form reverse micelles to facilitate extraction. The highly polar favipiravir molecules would be incorporated into the hydrophilic core of the formed reverse micelle to be extracted by the non-polar organic extractant. The method was validated according to the FDA bioanalytical method guidelines. The developed method was found linear in the concentration range of 0.1 to 100 µg/mL with a coefficient of determination of 0.9992. The method accuracy and precision were studied by calculating the recovery (%) and the relative standard deviation (%), respectively. The recovery (%) was in the range of 97.1-103.9%, while the RSD (%) values ranged between 2.03 and 8.15 %. The developed method was successfully applied in a bioequivalence study of Flupirava® 200 mg versus Avigan® 200 mg, after a single oral dose of favipiravir administered to healthy adult volunteers. The proposed method was simple, cheap, more eco-friendly and sufficiently sensitive for biomedical application.

Amides/isolation & purification , Antiviral Agents/isolation & purification , COVID-19/drug therapy , Liquid Phase Microextraction/methods , Pyrazines/isolation & purification , Amides/administration & dosage , Amides/blood , Antiviral Agents/administration & dosage , Antiviral Agents/blood , COVID-19/blood , COVID-19/virology , Chromatography, High Pressure Liquid/methods , Humans , Liquid Phase Microextraction/instrumentation , Menthol/chemistry , Pyrazines/administration & dosage , Pyrazines/blood , SARS-CoV-2/drug effects , SARS-CoV-2/physiology