Matrix Effects Research Articles

A modified QuEChERS-based UPLC-MS/MS method for rapid determination of multiple antibiotics and sedative residues in freshwater fish

Antibiotics and sedatives are used in freshwater fish culture and transportation, and residue in freshwater fish pose potential risks to human health. Therefore, a throughput method was developed to detect antibiotic and sedative residues in fish, simultaneously quantifying 68 antibiotics and 9 sedatives in freshwater fish using a modified QuEChERS extraction method and UPLC-MS/MS. Matrix-matched calibrations demonstrated good correlation coefficients (R2 > 0.995), with a recovery range of 66.2–118.5%. The intra-day and inter-day relative standard deviation (RSD) were below 9.7% and 12.8%, respectively. The limits of detection (LOD) and quantification (LOQ) were 0.08–1.46 μg/kg and 0.25–4.86 μg/kg, respectively. 68.8% of analytes had weak matrix effects, and 13.0% had moderate matrix effects. In addition, diazepam and many types of antibiotics were detected in30 freshwater fish. The validation parameters were in agreement with the acceptable criteria of the Codex guidelines. The method was effective in analyzing antibiotic and sedative residues in freshwater fish.

Determination of vancomycin and meropenem in serum and synovial fluid of patients with prosthetic joint infections using UPLC-MS/MS.

Numerous studies have suggested that intra-articular administration of antibiotics following primary revision surgery may be one of the methods for treating prosthetic joint infection (PJI). Vancomycin and meropenem are the two most commonly used antibiotics for local application. Determining the concentrations of vancomycin and meropenem in the serum and synovial fluid of patients with PJI plays a significant role in further optimizing local medication schemes and effectively eradicating biofilm infections. This study aimed to establish a rapid, sensitive, and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determining the concentrations of vancomycin and meropenem in human serum and synovial fluid. Serum samples were processed using acetonitrile precipitation of proteins and dichloromethane extraction, while synovial fluid samples were diluted before analysis. Chromatographic separation was achieved in 6min on a Waters Acquity UPLC BEH C18 column, with the mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Quantification was carried out using a Waters XEVO TQD triple quadrupole mass spectrometer with an electrospray ionization (ESI) source in positive ion mode. The multiple reaction monitoring (MRM) mode was employed to detect the following quantifier ion transitions: 717.95-99.97 (norvancomycin), 725.90-100.04 (vancomycin), 384.16-67.99 (meropenem). The method validation conformed to the guidelines of the FDA and the Chinese Pharmacopoeia. The method demonstrated good linearity within the range of 0.5-50 μg/ml for serum and 0.5-100 μg/ml for synovial fluid. Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, matrix effect, and stability validation results all met the required standards. This method has been successfully applied in the pharmacokinetic/pharmacodynamic (PK/PD) studies of patients with PJI.

Alkanediol–hexafluoroisopropanol amphiphilic supramolecular solvent: Fabrication, characterization, and application potential for doping control of hormones and metabolic modulators in human urine

A novel amphiphilic supramolecular solvent (SUPRAS) was developed by hexafluoroisopropanol (HFIP)-induced self-assembly of 1,2-hexanediol in an aqueous matrix. Its application potential in multiclass determination was assessed by extracting from urine 10 prohibited hormones and metabolic modulators (log P from 2.38 to 7.57) listed by the World Anti-Doping Agency (WADA). This SUPRAS is stably formed across a wide pH range (2–12) and is unaffected by salt concentrations (<10 % g mL−1 of NaCl), and it has a higher density than water. The dehydration and hydrogen bonding ability of HFIP, as well as hydrophobic interactions between alkanediols, dominates the formation of the SUPRAS. The nanostructure of the SUPRAS, composed of 1,2-hexanediol, HFIP, and a high content of water (>25 %, w/w), forms large spherical micellar aggregates (10–100 μm) that exhibit amphiphilic properties. A 1,2-hexanediol-HFIP SUPRAS-based liquid-phase microextraction (LPME) method for detection of selected prohibited drugs in urine coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS) was established, optimized, and validated. The method showed fast extraction time (30 s of vortex) and low solvent consumption (160 μL of organic solvent). Under the optimal conditions (7 % g mL−1 of 1,2-hexanediol, 10 % v/v of HFIP), the SUPRAS achieved high extraction efficiencies (>80 %) and an enrichment factor of 6.0, with minimal matrix effects for all analytes due to its high amphiphilicity and large surface area. The method demonstrated excellent linearity (R ≥ 0.9909), with method limits of detection ranging from 0.018 to 0.18 ng mL−1 and method limits of quantitation ranging from 0.060 to 0.60 ng mL−1, which are well below the minimum required performance levels set by authorities. Furthermore, the intra- and inter-day relative recoveries for spiked human urine samples varied in the ranges of 90.3 %–121 % and 88.1–119 %, respectively, with relative standard deviations less than 13 % and 19 %, respectively. This SUPRAS-based LPME method proves to be simple, highly efficient, and eco-friendly, and it has promising potential for multiclass determination in doping control.

Pharmacokinetic and oral bioavailability study of schaftoside in rats.

A simple and sensitive LC-tandem mass spectrometry method was established and validated for the determination of schaftoside in rat plasma. After prepared by protein precipitation with acetonitrile, schaftoside and internal standard were separated on a Waters HSS T3 column using acetonitrile containing 0.1% formic acid and 0.1% formic acid in water as the mobile phase by gradient elution. The method showed excellent linearity over the range of 0.5-500 ng/mL with acceptable intra- and inter-day precision, accuracy, matrix effect, and recovery. The stability assay indicated that schaftoside was stable during the sample acquisition, preparation, and storage. The method was applied to a pharmacokinetic study of schaftoside in rats. The result suggested that after intravenous administration at a dose of 1 mg/kg, schaftoside was quickly eliminated from the plasma with an elimination half-life of 0.58 h. After oral administration at doses of 5, 10, and 20 mg/kg, schaftoside was quickly absorbed into the plasma and reached the peak concentration (Cmax) of 45.1-104.99 ng/mL at 0.67-1.17 h. The increase of exposure (area under the curve) was linear with the increase of dose. The oral bioavailability was 0.42%-0.71% in the range of 5-20 mg/kg.

A red-fleshed apple rich in anthocyanins improves endothelial function, reduces inflammation, and modulates the immune system in hypercholesterolemic subjects: the AppleCOR study.

The study determines the sustained and acute effects of a red-fleshed apple (RFA), rich in anthocyanins (ACNs), a white-fleshed apple (WFA) without ACNs, and an infusion from Aronia melanocarpa (AI) with an equivalent content of ACNs as RFA, on different cardiometabolic risk biomarkers in hypercholesterolemic subjects. A randomized, parallel study was performed for 6 weeks and two dose-response studies were performed at the baseline and after intervention. At 6 weeks, RFA consumption improved ischemic reactive hyperemia and decreased C-reactive protein and interleukine-6 compared to WFA consumption. Moreover, at 6 weeks, AI decreased P-selectin compared to WFA and improved the lipid profile. Three products reduced C1q, C4 and Factor B, and RFA and AI reduced C3. Although both RFA and AI have a similar ACN content, RFA, by a matrix effect, induced more improvements in inflammation, whereas AI improved the lipid profile. Anti-inflammatory protein modulation by proteomic reduction of the complement system and immunoglobulins were verified after WFA, AI and RFA consumption.

Emerging mycotoxin occurrence in chicken feed and eggs from Algeria.

Poultry farming has developed into one of Algeria's most productive industrial farming because of the growing demand for sources of protein among Algerian society. Laying hen feed consists mainly of cereals, which can be contaminated with molds and subsequently with their secondary metabolites known as mycotoxins. These later can pose a serious danger to the production and quality of eggs in the commercial layer industry. This work focuses on the detection of emerging mycotoxins, mainly enniatins (ENNs) and beauvericin (BEA), in poultry feed and eggs from different locations in Algeria. Two different QuEChERS-based extractions were established to extract ENNs and BEA from chicken feed and eggs. The determination of mycotoxin occurrence was achieved by a UHPLC-MS/MS method using 0.1% (v/v) formic acid in water and MeOH as mobile phase, an ESI interface operating in positive mode, and a triple quadrupole mass spectrometer operating in MRM for the detection. Matrix-matched calibration curves were carried out for both matrices, obtaining good linearity (R2 > 0.99). The method performance was assessed in terms of extraction recovery (from 87 to 107%), matrix effect (from - 47 to - 86%), precision (RSD < 15%), and limits of quantitation (≤ 1.1µg/kg for feed and ≤ 0.8µg/kg for eggs). The analysis of 10 chicken feed samples and 35 egg samples composed of a 10-egg pool each showed that ENN B1 was the most common mycotoxin (i.e., found in 9 feed samples) with contamination levels ranging from 3.6 to 41.5µg/kg, while BEA was detected only in one feed sample (12µg/kg). However, eggs were not found to be contaminated with any mycotoxin at the detection limit levels. Our findings indicate that the searched mycotoxins are present in traces in feed and absent in eggs. This can be explained by the application of a mycotoxin binder. However, this does not put a stop on the conduction of additional research and ultimately setting regulations to prevent the occurrence of emerging mycotoxins.

Validation and Application of a Dried Blood Spot Amoxicillin Assay

AbstractDried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK) investigations in situations where venous blood sampling is logistically and/or ethically challenging. The aim of this study was to establish, validate and demonstrate the application of a DBS amoxicillin assay for PK studies in vulnerable populations. The matrix effect, process efficiency (84–104%) and recovery (85–110%) of the liquid chromatography–mass spectrometry (LC–MS/MS) assay for amoxicillin in DBS was determined at 1, 10 and 100 µg/mL, and three different haematocrits. Thermal stability studies of amoxicillin in DBS were performed and a bridging study comprising 26 paired plasma and DBS samples was conducted in four healthy individuals. The limits of detection and quantification were 0.02 and 0.05 µg/mL for plasma and DBS amoxicillin assays, respectively. Accuracy and interday precision of amoxicillin in DBS (0.1–100 µg/mL) were 88–103% and 4.5–9.2%, respectively. At room temperature (22 °C) and 4 °C, amoxicillin was stable in DBS for ≈4 and 26 h, respectively. There was no degradation of amoxicillin in DBS at −20 °C for &gt; 6 months. When comparing DBS and plasma collected from healthy volunteers, the slope of the Deming regression was 0.74. Amoxicillin CL/F estimates from DBS and plasma concentration data were 40.8 and 30.7 L/h/70 kg, respectively; V/F was 43.2 and 37.4 L/70 kg, respectively. In conclusion, amoxicillin can be reliably assayed from DBS in research studies but may have limited application in therapeutic drug monitoring. Due to poor stability at room temperature, amoxicillin DBS samples should be promptly dried and placed in frozen storage.

Fluorescent and Colorimetric Dual-Readout Immunochromatographic Assay for the Detection of Phenamacril Residues in Agricultural Products.

The fungicide phenamacril has been employed to manage Fusarium and mycotoxins in crops, leading to persistent residues in the environment and plants. Detecting phenamacril is pivotal for ensuring environmental and food safety. In this study, haptens and artificial antigens were synthesized to produce antiphenamacril monoclonal antibodies (mAbs). Additionally, gold nanoparticles coated with a polydopamine shell were synthesized and conjugated with mAbs, inducing fluorescence quenching in quantum dots. Moreover, a dual-readout immunochromatographic assay that combines the positive signal from fluorescence with the negative signal from colorimetry was developed to enable sensitive and precise detection of phenamacril within 10 min, achieving detection limits of 5 ng/mL. The method's reliability was affirmed by using spiked wheat flour samples, achieving a limit of quantitation of 0.05 mg/kg. This analytical platform demonstrates high sensitivity, outstanding accuracy, and robust tolerance to matrix effects, making it suitable for the rapid, onsite, quantitative screening of phenamacril residues.

Post column infusion of an internal standard into LC-FT-ICR MS enables semi-quantitative comparison of dissolved organic matter in original samples.

Ultrahigh resolution mass spectrometry hyphenated with liquid chromatography (LC) is an emerging tool to explore the isomeric composition of dissolved organic matter (DOM). However, matrix effects limit the potential for semi-quantitative comparison of DOM molecule abundances across samples. We introduce a post-column infused internal standard (PCI-IS) for reversed-phase LC-FT-ICR MS measurements of DOM and systematically evaluate matrix effects, detector linearity and the precision of mass peak intensities. Matrix effects for model compounds spiked into freshwater DOM samples ranging from a headwater stream to a major river were reduced by 5-10% for PCI-IS corrected mass peak intensities as compared to raw (i.e., untransformed) intensities. A linear regression of PCI-IS corrected DOM mass peak intensities across a typical DOM concentration range (2-15 mg dissolved organic carbon L-1) in original, non-extracted freshwater samples demonstrates excellent linearity of the detector response (r2 > 0.9 for 98% of detected molecular formulas across retention times). Importantly, PCI-IS could compensate for 80% of matrix effects across an environmental gradient of DOM composition from groundwater to surface water. This enabled studying the ionization efficiency of DOM isomers and linking the observed differences to the biogeochemical sources. With PCI-IS original, non-extracted DOM samples can be analysed by LC-FT-ICR MS without carbon load adjustment, and mass peak intensities can be reliably used to semi-quantitatively compare isomer abundances between compositionally similar DOM samples.

High-Performance Liquid Chromatographic Quantification of the Plant Hormone Abscisic Acid at ppb Levels in Plant Samples after a Single Immunoaffinity Column Cleanup.

High-performance liquid chromatography with ultraviolet detection (HPLC-UV) is a common analysis technique due to its high versatility and simple operation. In the present study, HPLC-UV detection was integrated with immunoaffinity cleanup (IAC) of the sample extracts. The matrix effect was greatly reduced, and the limit of detection was as low as 1 ng/g of free abscisic acid (ABA) in fresh plant tissues. A monoclonal antibody 3F1 (mAb 3F1) was developed to specifically recognize free ABA but not ABA analogues. The mAb 3F1-immobilized immunoaffinity column exhibited a capacity of 850 ng/mL and an elution efficiency of 88.8-105% for standards. The extraction recoveries of the column for ABA ranged from 80.4 to 108.9%. ABA content was detected in various plant samples with IAC-HPLC-UV. The results were verified with ultraperformance liquid chromatography-electrospray tandem mass spectrometry. IAC-HPLC-UV can be a sensitive and cost-efficient method for plant hormone analysis.

Determination of pancratistatin in mouse blood by ultra-liquid chromatography-tandem quadrupole mass spectrometry and its application

AbstractIn this study, a UPLC-MS/MS method was developed for determination of pancratistatin in the mouse blood, and the pharmacokinetics of pancratistatin in mice after intravenous (5 mg kg−1) and intragastric (15 mg kg−1) administration was studied. HSS T3 column was used for separation with mobile phases of acetonitrile and 0.1% formic acid using gradient elution procedure. The blood sample was treated by protein precipitant with acetonitrile, midazolam was used as internal standard (IS). Multiple reaction monitoring mode (MRM) was used for quantitative analysis, m/z 326.2→83.8 for pancratistatin and m/z 326.2→291.4 for IS in electrospray (ESI) positive interface. It showed a good linear in the range of 10–4,000 ng mL−1 (r &gt; 0.998); the intra-day and inter-day precision was &lt;15%, and the accuracy was 93%–105%. The recovery was better than 82%, and the matrix effect was 94%–105%. The developed UPLC-MS/MS method was fast, selective, and suitable for the pharmacokinetics of pancratistatin in mice.

Allopregnanolone in the peripartum: Correlates, concentrations, and challenges – A systematic review

BackgroundAllopregnanolone (ALLO) is a metabolite of progesterone and a neuroactive steroid hormone. As a positive allosteric modulator of gamma-aminobutyric acid (GABA) receptors, ALLO seems to have antidepressant and anxiolytic effects, and was therefore approved as a specific medication for the treatment of postpartum depression in 2019. Despite the growing number of publications investigating ALLO levels, results on the biological and psychological correlates in the peripartum period remain inconsistent, possibly due to methodological challenges regarding measurement. To date, however, there is no systematic review examining the correlates, concentrations, and challenges in measuring ALLO in peripartum women. MethodA systematic literature search of PubMed and PsycINFO was conducted in August 2023. Original research articles that measured ALLO concentrations in peripartum women were included. Reports were excluded if they were not original research, included non-human subjects, did not include peripartum women, did not include ALLO measurement as an outcome, included (pharmacological) interventions, constituted method validations, or used the same cohort as another study. ResultsThe literature search yielded 234 articles, and two articles were identified from other sources. After full-text screening, 19 articles (N = 1401) met the inclusion criteria, of which seven focused on biological correlates of ALLO and 12 on mood correlates. Of the latter, six found no association between ALLO and mood, four found a negative association, and two found a positive association. Overall, the results show an increase in ALLO levels during pregnancy and a decrease after birth, with levels then remaining low until six months postpartum. ALLO was most commonly measured in blood plasma and by gas chromatography-mass spectrometry (GC-MS). A significant matrix effect was found for blood serum and a significant method effect for radioimmunoassays (RIAs). A significant effect of time of measurement was found. ConclusionALLO measurement shows method and matrix effects. ALLO levels are higher when measured in serum compared to in plasma, and when measured using RIA compared to other methods. Time of measurement, study design, and standardization of measurement also influence the reliability of measurement and the interpretation of results.

Validation of the rapid and simple LC-MS/MS method for the quantification of pregabalin in plasma of acutely poisoned patients

AbstractPregabalin is a gabapentinoid approved for the treatment of general anxiety disorder, neuropathic pain and as adjunctive therapy for focal seizures in patients with epilepsy. In addition, there are a number of conditions for which pregabalin is prescribed off-label. Along with the widespread use there are a significant number of reports describing the misuse of pregabalin over the last decade. Over time, it became clear that pregabalin should become part of routine testing in toxicology laboratories. The aim of this paper was to present validation of a LC-MS/MS method for the quantification of pregabalin in plasma of acutely poisoned patients. Simple sample preparation step and rapid chromatographic separation shortened the overall analysis time, which was the goal of method development. The presence of pregabalin was confirmed with three ion transitions, ensuring high selectivity of the validated method. The statistical data obtained showed good precision and accuracy over a wide concentration range. No endogenous or other interference was detected, and there was no matrix effect influence with this method. The LC-MS/MS method was applied to quantify pregabalin in plasma samples of patients admitted to the emergency department due to a possible acute pregabalin overdose. Different concentrations were found, and we report, to the best of our knowledge, the highest plasma concentration of pregabalin in the plasma of a patient with acute poisoning. In conclusion, we developed a fast and simple LC-MS/MS method for reliable determination of pregabalin and demonstrated the developed method was suitable for routine use in clinical toxicology setting.

Ultrasonic-induced grafted lanthanum sulfide decorated multi-walled carbon nanotube onto bacterial cellulose applied for adsorption of pesticides in environmental waters

A new biosorbent was fabricated by modification of bacterial cellulose biopolymer grafted with lanthanum sulfide decorated carboxylated multiwall carbon nanotube (La2S3@MWCNT@BC). The sorbent was employed in a green alternative dispersive-solid phase extraction of a variety of 14 pesticides in environmental water samples. The analyses were performed using GC-µECD. The properties and structure of La2S3@MWCNT@BC nanocomposite were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and adsorption-desorption isotherms. The composition of the sorbent was also investigated to evaluate the adsorptive properties of its constituents. The impact of various parameters influencing extraction efficacies such as sorbent dose, adsorption time, sample pH, ionic strength, and desorption conditions was investigated. The method was validated by specificity, matrix effect % (-0.4 to -7.4), enrichment factor (4–10), limits of quantification (0.007–0.31 μg L−1), matrix-matched calibration linearity (0.01–200 µg L−1), determination coefficients (r2=0.9921–0.9998), and precision. The optimized method was applied for the analysis of multiclass pesticides in seven environmental and drinking waters and the recoveries were obtained in the 81–108 % range with RSDs of 2.5–4.7 %. This paper is the first report on the synthesis and use of La2S3@MWCNT@BC nanocomposite to extract pesticides from different water samples. The greenness of the procedure was evaluated by the AGREE protocols.

A validated high‐performance liquid chromatography‐tandem mass spectrometry method for simultaneous determination of irinotecan and two major metabolites in rat plasma: Application for the pharmacokinetics study

AbstractA high‐performance liquid chromatography‐tandem mass spectrometry method has been developed for the determination of irinotecan, 7‐ethyl‐10‐hydroxycamptothecin (SN38), and SN38 glucuronide (SN38G) in rat plasma in the present study. The analytes were separated on a C18 column and a triple‐quadrupole mass spectrometry equipped with an electrospray ionization source was applied for detection. Irinotecan, SN38 and SN38G could be well retained in the C18 column after optimization of mobile phase. A simple protein precipitation was used to pretreat the plasma. The extraction recovery was above 90% and the matrix effect could be negligible. The method was linear over the concentration ranges of 3.46–3458.8 ng/mL for irinotecan, 2.53–2530.0 ng/mL for SN38 and 2.5–2500.0 ng/mL for SN38G. The precision and accuracy was within the acceptable limits. The simple and convenient method was validated and successfully applied to support the pharmacokinetic study and elucidate the mechanism of irinotecan‐induced diarrhea after irinotecan was intravenously injected to the Sprague‐Dawley rats.

Ion chromatography‐based determination of lithium in human urine for monitoring medication compliance

AbstractContinuous Li monitoring is vital in ensuring the safety and treatment efficacy of probationers with psychotic disorders, such as bipolar disorder, depression, and mania. This study introduced a validated quantitative analysis method using ion chromatography (IC) to monitor Li+ concentration in urine. The methodology involved centrifuging the urine sample, diluting the supernatant with deionized water, and subsequent IC analysis using guard and analytical columns for precise Li+ concentration measurement. The method quantified Li+ within the range of 2–400 ng/mL, demonstrating its excellent linearity (r2 = 0.9983) with a weighting factor of 1/x. Precision levels below 12.8% were observed for both intraday and interday measurements with an accuracy of −5.9% to 15.2%. The detection limit was identified as 0.12 ng/mL. The method conformed to analytical standards in terms of selectivity, matrix effect, process efficiency, dilution integrity, and stability. Moreover, the method distinctly quantified Li+ while effectively eliminating interference from Na+, which had a similar retention time as Li+ with higher concentrations. Further, the developed method was successfully applied to analyze forensic urine samples of Li users, demonstrating its applicability for medication compliance monitoring using urine samples of mentally disordered probationers.

Accurate analysis of coal calorific value using NIRS-XRF: Utilizing RF classification and PLSR subtype modeling

Rapid and precise measurement of the calorific value of coal is crucial for coal chemical enterprises. However, due to the wide variety of coal sources and the diverse types of coal, the matrix effect significantly reduces the accuracy of spectroscopic rapid detection techniques for coal quality. To address this issue, this study conducts research on a coal calorific value detection method based on the combined use of near-infrared spectroscopy (NIRS) and X-ray fluorescence spectroscopy (XRF), exploring the feasibility of identifying coal types first and then predicting calorific value based on corresponding subtype models. In the aspect of spectral preprocessing, fusion of the dual spectra is achieved using techniques such as truncation, smoothing, Standard Normal Variate (SNV), and normalization. For coal type identification, the identification performance of five machine learning algorithms is compared, and the random forest (RF) algorithm is used to improve the identification accuracy to 98.43 %. In terms of prediction modeling, a comparison is made between traditional holistic models based on Partial Least Squares Regression (PLSR) and subtype models built according to coal types, revealing that the latter demonstrating stronger generalization ability and robustness. Accordingly, a precise prediction strategy for coal calorific value based on the combined use of NIRS and XRF in complex coal types is proposed: first, the RF algorithm is used to automatically identify coal types based on the fusion spectrum of NIRS and XRF, and then the calorific value of the corresponding coal type is accurately predicted using the PLSR subtype model selected according to the identification results. Industrial test results indicate that the average absolute error (AAE), root mean square error of prediction (RMSEP), average relative error (ARE), and standard deviation (SD) for coal calorific value prediction are 0.20 MJ/kg, 0.24 MJ/kg, 0.79 %, and 0.04 MJ/kg, respectively, meeting the requirements of enterprises. The research findings provide a practical technical method for timely and accurate acquisition of coal calorific value data, addressing the interference problem of matrix effects in complex coal type scenarios and holding broad application prospects in the coal-based energy industries.

Codetermination of antimicrobial agents in rabbit tear fluid using LC-MS/MS assay: Insights into ocular pharmacokinetic study.

Managing ocular microbial infections typically requires pharmacotherapy using antibiotic eye drops, such as moxifloxacin hydrochloride (MFX), combined with an antifungal agent like amphotericin B (AB). We carried out and validated an LC-MS/MS assay to quantify these compounds in rabbit tear fluid in order to look into the pharmacokinetics of these two drugs. We employed a protein precipitation technique for the extraction of drugs under examination. A Waters Symmetry C18 column was used to separate the analytes and internal standard. The composition of the mobile phase was like (A) 0.1% v/v formic acid in water and (B) methanol. The detection of MFX and AB was accomplished through the utilization of positive ion electrospray ionization under multiple reaction monitoring mode. The linearity curves for both analytes exhibited an acceptable trendline across a concentration range of 2.34-300 ng/mL for MFX and 7.81-1000 ng/mL for AB in surrogate rabbit tear fluid. The lower limit of quantitation for MFX was 2.34 ng/mL, while for AB, it was 7.81 ng/mL. The approach was strictly validated, encompassing tests of selectivity, linearity (with r2>0.99), precision, accuracy, matrix effects, and stability. Consequently, we employed this method to evaluate the pharmacokinetics profiles of MFX and AB in rabbit tear fluid following single topical doses.

Simultaneous Quantification of Vancomycin, Linezolid and Voriconazole in Human Plasma by UHPLC–MS/MS: Application in Therapeutic Drug Monitoring

Abstract Objective Individual differences challenge the treatment of vancomycin, linezolid and voriconazole in severe infections. This study aimed to build a simple and economical method for simultaneous determination of the three antibiotics in human plasma by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) and provided a reference for therapeutic drug monitoring (TDM) of infected patients. Methods The plasma samples were precipitated by acetonitrile and detected and separated on a shim-pack GIST C18 column following the gradient elution within 5 min. Mass quantification was performed on multiple reaction monitoring mode under positive electrospray ionization. Results The linear ranges of vancomycin, linezolid and voriconazole were 1.00–100.00, 0.10–15.00 and 0.10–20.00 μg·mL−1, respectively, with good linearity (R2 &amp;gt; 0.99). The accuracy and precision, matrix effect, extraction recovery and stability were validated, and the results all meet the acceptance criteria of China Food and Drug Administration (CFDA) guidelines. Conclusion The UHPLC–MS/MS method was established and validated for the simultaneous determination of vancomycin, linezolid and voriconazole in human plasma and successfully applied to routine TDM for individualized treatment.

A simple, rapid, and green method for determination of three cholic acids in bio-transformed Jindanfen by HPLC-MS

AbstractA simple, rapid, and green high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for determination of tauroursodeoxycholic acid (TUDCA), taurocholic acid (TCA), and taurochenodeoxycholic acid (TCDCA) in bio-transformed Jindanfen (BTJDF), which is obtained from chicken bile through a bioconversion process. The sample was prepared using water. The HPLC separation was operated on a poroshell 120 EC-C18 column with a 2.0 min gradient elution procedure. Detection was performed on a single quadrupole mass spectrometer in negative mode with selected ion monitoring mode (SIM). This developed HPLC-MS method presented good linearity (r &gt; 0.997) and sensitivity (limit of quantification, 30.0–80.0 pg) for three analytes. The relative standard deviations (RSDs) for precision, repeatability, and stability were all below 3.00%. The matrix effects and average recoveries of three analytes were 91.2–97.9% (RSDs &lt; 1.50%) and 95.4–103% (RSDs &lt; 3.00%), respectively. The average contents of TUDCA, TCA, and TCDCA in ten batches of samples were 33.8, 13.2, and 20.5%, respectively. Finally, the greenness of the developed method was validated by Analytical Eco-Scale and Complex-GAPI. The developed method was proved to be an eco-friendly, effective, and reliable approach for assaying the three cholic acids in BTJDF, which is help to improve the quality evaluation level of the BTJDF industry.