LC-MS/MS Method for Determination of Hydroxychloroquine and Metabolites: Application in a Pharmacokinetic Study

A LC-MS/MS Method for Quantifying the Schisandrin B and Exploring Its Intracellular Exposure Correlating Antitumor Effect

Schisandrin B (Sch.B) shows antineoplastic activity in colorectal cancer, but the mechanism is still obscure. The intracellular spatial distribution may be helpful in elucidating the mechanism. To investigate the intracellular drug distribution of Sch.B in cancer cells, a simple, rapid, and sensitive ultra-highperformance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was established for the determination of Sch.B in colorectal cancer cells. Warfarin was utilized as an internal standard. The sample pretreatment was carried out with protein precipitation using methanol. The analyte was separated on an Atlantis T3-C₁₈ column (3 μm, 2.1∗100 mm) using gradient elution with a mobile phase comprised of methanol and 0.2% formic acid in water. The flow rate was 0.4 mL/min. The linear range of Sch.B was 20.0-1000.0 ng/mL with a correlation coefficient (R) more than 0.99. The matrix effect and recovery ranged from 88.01% to 94.59% and from 85.25% to 91.71%; the interday and intraday precision and accuracy, stability, specificity, carryover, matrix effect, and recovery all conformed to the requirements of pharmacopoeia. Cell viability and apoptosis assays demonstrated that Sch.B has an inhibitory effect in a dose-dependent way on HCT116 proliferation and achieved significant suppression at 75 μM (IC₅₀). It was found that in HCT116 cell, nucleus, and mitochondria, exposure levels of Sch.B peaked at 36 h and then decreased, and mitochondria possessed more Sch.B than nucleus. These results may help to elucidate the antitumor effect of Sch.B.

The ecological impact of liquid chromatographic methods reported for bioanalysis of COVID-19 drug, hydroxychloroquine: Insights on greenness assessment

Hydroxychloroquine is a drug that has been widely used during the early stages of COVID-19 pandemic. Different liquid chromatographic methods have been reported for the analysis of hydroxychloroquine in various biological matrices such as human plasma, serum, whole blood, oral fluid, rat plasma and tissues . In this comparative study, the most popular tools used for assessing the greenness profile: National Environmental Methods Index (NEMI), Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI) and Analytical Greenness metric (AGREE) were utilized to evaluate the ecological impact of eighteen liquid chromatographic methods developed for the bioanalysis of COVID-19 drug; hydroxychloroquine.

NEMI is the simplest tool for evaluating the greenness profile of developed methods, but it is the least informative approach as all the reported methods had the same NEMI pictograms. On the other hand, GAPI is a dependable tool providing a complete picture about the method greenness starting from sampling until the final determination. ESA and AGREE tools are digitally presented and more easily applied. Therefore, their utilization for greenness assessment is highly recommended. Selection of the highest eco-friendly analytical procedure is of a paramount importance for protecting human health and the environment. Considering the greenness of the analytical procedures is highly recommended before proceeding to routine use in order to minimize the chemical hazards to the environment. The most eco-friendly analytical procedures for the analysis of hydroxychloroquine in biological samples according to ESA, GAPI and AGREE tools will be highlighted and discussed.

Pharmacokinetic Study of Coadministration with Cefuroxime Sodium for Injection Influencing ReDuNing Injection-Derived Seven Phytochemicals and Nine Metabolites in Rats

According to the sixth edition of China's "New Coronavirus Diagnosis and Treatment Plan (NCDTP)," ReDuNing injection (RDN) was firstly introduced to treat severe and critical COVID-19, whereas its combination with broad-spectrum antibiotics was suggested to take with extreme caution and full reasons. Therefore, we aim to describe the pharmacokinetics of seven active phytochemicals and semiquantification of nine relevant metabolites in ReDuNing injection (RDN) after combining with cefuroxime sodium (CNa) for injection in rat plasma. Male Sprague-Dawley rats were randomly assigned to six groups, and they were intravenously administered, respectively, with different prescriptions of RDN (2 mL/kg) and CNa (225 mg/kg). At different time points (0.03, 0.08, 0.17, 0.24, 0.33, 0.50, 0.67, 1, and 6 h) after administration, the drug concentrations of iridoids glycosides, organic acids, and metabolites in rat plasma were determined using ultrahigh-pressure liquid chromatography coupled with linear ion rap-orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS), and main pharmacokinetic parameters were estimated by noncompartment model. The results showed that there were differences in pharmacokinetic parameters, AUC_(0-t), T_1/2, C _max, CL of iridoids glycosides, and organic acids, after the intravenous administration of the different combinations of RDN and CNa. Moreover, different combinations of the injections also resulted in different curves of relative changes of each metabolite. The obtained results suggested that RDN and CNa existed pharmacokinetic drug-herb interactions in rats. The findings not only lay the foundation for evaluating the safety of RDN injection combined with CNa but also make contributions to clinically applying RDN injection combined with CNa, which works potentially against severe forms of COVID-19.