During the last decade, a significant increase in the occurrence of harmful algal blooms (HABs), linked to repetitive cases of shellfish contamination has become a public health concern and therefore, accurate methods to detect marine toxins in different matrices are required. In this study, we developed a method for profiling lipophilic marine microalgal toxins based on ultra-high-performance liquid chromatography coupled to high-resolution Orbitrap mass spectrometry (UHPLC-HR-Orbitrap MS). Extraction of selected toxins (okadaic acid (OA), dinophysistoxin-1 (DTX-1), pectenotoxin-2 (PTX-2), azaspiracid-1 (AZA-1), yessotoxin (YTX) and 13-desmethyl spirolide C (SPX-1)) was optimized using a Plackett-Burman design. Three key algal species, i.e., Prorocentrum lima, Protoceratium reticulatum and Alexandrium ostenfeldii were used to test the extraction efficiency of OA, YTXs and SPXs, respectively. Prorocentrum micans, fortified with certified reference solutions, was used for recovery studies. The quantitative and confirmatory performance of the method was evaluated according to CD 2002/657/EC. Limits of detection and quantification ranged between 0.006 and 0.050 ng mL(-1) and 0.018 to 0.227 ng mL(-1), respectively. The intra-laboratory reproducibility ranged from 6.8 to 11.7 %, repeatability from 6.41 to 11.5 % and mean corrected recoveries from 81.9 to 119.6 %. In addition, algae cultures were retrospectively screened for analogues and metabolites through a homemade database. Using the ToxID software programme, 18 toxin derivates were detected in the extract of three toxin producing microalgae species. In conclusion, the generic extraction and full-scan HRMS approach offers an excellent quantitative performance and simultaneously allows to profile analogues and metabolites of marine toxins in microalgae. Graphical Abstract Optimization of extraction, detection and quantification of lipophilic marine toxins in microalgae by UHPLC-HR Orbitrap MS.
Purpose: To evaluate saturation of piperacillin elimination in adult critically ill patients. Patients and methods: Seventeen adult critically ill patients received continuous and intermittent infusion piperacillin/tazobactam. Piperacillin plasma concentrations (n=217) were analyzed using population pharmacokinetic (PopPK) modeling. Post hoc simulations were performed to evaluate the type I error rate associated with our study. Unseen data was used to validate the final model. The mean error (ME) and root mean squared error (RMSE) were calculated as a measure of bias and imprecision respectively. Results: A PopPK model with parallel linear and non-linear elimination best fitted our data. The median and 95% confidence intervals for model parameters drug clearance (CL), volume of the central compartment (V), volume of the peripheral compartment (Vp) and intercompartmental clearance (Q) were 9 (7.69-11) L/h, 6.18 (4.93-11.2) L, 11.17 (7.26-12) L and 15.61 (12.66-23.8) L/h. The Michaelis-Menten constant (Km) and the maximum elimination rate for Michaelis-Menten elimination (Vmax) were estimated without population variability in the model to avoid overfitting and inflation of the type I error rate. The population estimates for Km and Vmax were 37.09 mg/L and 353.57 mg/h respectively. The ME was-20.8 (95% CI-26.2;-15.4) mg/L while imprecision (RMSE) was 49.2 (95% CI 41.2; 56) mg/L Conclusion: Piperacillin elimination is (partially) saturable. Moreover, the population estimate for Km lies within the therapeutic window and therefore saturation of elimination should be accounted for when defining optimum dosing regimens for piperacillin in critically ill patients.
An ultra-high pressure liquid chromatography high-resolution mass spectrometric (UHPLC-HRMS) method was developed for the simultaneous and sensitive quantification of 10 β-lactam antibiotics (cefepime, meropenem, amoxicillin, cefazolin, benzylpenicillin, ceftazidime, piperacillin, flucloxacillin, cefuroxime and aztreonam), linezolid and β-lactamase inhibitors tazobactam and clavulanic acid in human plasma. Validation according to the EMA guidelines showed excellent withinand between-run accuracy and precision (i.e. between 1.1 and 8.5%) and high sensitivity (i.e. lower limit of quantification between 0.25 and 1 mg/L). The UHPLC-HRMS method enables a short turnaround time and high sensitivity and needs only a small amount of plasma, allowing appropriate routine therapeutic drug monitoring.The short turnaround time is obtained by speeding up the protocol on multiple levels, i.e. fast and workload-efficient sample preparation (i.e. protein precipitation and dilution), short (4 min) instrument run time, simultaneous measurement of all relevant β-lactam antibiotics used in the intensive care unit and the use of the same instrument, column and mobile phases as for the other routine methods in our laboratory. K E Y W O R D Sβ-lactam antibiotics, HRMS, therapeutic drug monitoring | INTRODUCTIONSevere infection and associated septic shock persist as significant healthcare concerns as they are the most common cause of mortality in critically ill patients worldwide (Vincent et al., 2009). Since adequate and early administration of antibiotics remains the mainstay of therapy for the treatment of severe infections, there is a high level of consumption of antibiotics in intensive care units (ICU) (Dellinger et al., 2013). A single-day point prevalence study showed that 71% of the ICU patients received antimicrobial therapy (Vincent et al., 2009). However, in specific patient populations like critically ill patients, cystic fibrosis patients, elderly patients, neonates, etc., the pharmacokinetics of these antibiotics may be profoundly disturbed owing to pathophysiological changes in distribution and elimination (Roberts et al., 2014;Taccone et al., 2010;Theuretzbacher, 2012). Consequently, an empirical fixed dose approach, in which every patient is treated according to the same dosing scheme, appears to be inadequate and can lead to excessive drug exposure with an increased risk of toxicity or inadequate drug exposure with clinical failure and/or antimicrobial resistance (Roberts & Lipman, 2006). Optimizing antibiotic dosing may be a key intervention, not only to improve clinical outcome and minimize toxicity, but also to prolong the clinical lifespan of the currently available antibiotics by limiting the emergence of
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.