Inter-batch Precision Research Articles

In vial thin-film solid-phase microextraction using silver nanoparticles as coating for the determination of phenols in waters

A novel thin-film solid-phase microextraction (TF-SPME) device based on glass vials internally coated with silver nanoparticles (AgNPs) was developed for the first time, and used for determining five phenols in wastewater, bottled water, and irrigation water samples by high-performance liquid chromatography coupled to a photodiode array detector (HPLC-PDA). Different AgNPs were synthesized varying the ratio of metallic salt versus the reduction agent, and the pH of the synthesis. The preparation of the TF-SPME glass vial device was optimized in terms of the type of AgNPs used and the number of layers of AgNPs. Besides, the TF-SPME procedure was also optimized. The TF-SPME method was very simple, only requiring the addition of 18 mL of water and 5 min of agitation, followed by the disposal of the water and addition of the 750 µL as desorption solvent, and direct HPLC-PDA injection. The entire method showed adequate analytical performance, with limits of detection ranging from 3 to 8 μg·L-1, and intra-day and inter-day precision (as RSD), both evaluated with different vials and therefore showing inter-batch precision, with values between 8.70 and 16.4 %, and 6.0 and 19.7 %, respectively. The TF-SPME-HPLC-PDA procedure was compared with previous methods for the determination of phenols, both in terms of analytical performance and greenness assessments applying different metrics, showing clear advantages.

Determination of 22 elements in whole blood by inductively coupled plasma mass spectrometry

Objective: To establish a method for the simultaneous determination of 22 elements, including beryllium, vanadium, chromium, manganese, iron, calcium, magnesium, barium, cobalt, cadmium, copper, zinc, arsenic, selenium, titanium, strontium, nickel, molybdenum, tin, antimony, thallium and lead, in whole blood by inductively coupled plasma mass spectrometry (ICP-MS) . Methods: In September 2023, the analysis conditions were determined by optimizing the detection mode of the instrument, the pretreatment mode and the dilution factor of the samples, etc. Whole blood samples were diluted with a mixture of 0.1% nitric acid and 0.05% triton X-100, and centrifuged at 2000 r/min by high-speed centrifuge for 2 min. The supernatant was taken into inductively coupled plasma mass spectrometer to determine the content of 22 elements, and the detection limit and precision of the method were analyzed. Results: The 22 elements had a good linear relationship in their respective measurement ranges (r=0.9991-0.9999), the detection limit ranged from 0.003 μg/L to 0.012 mg/L. The intra-batch precision ranged from 0.5% to 7.2%, the inter-batch precision ranged from 0.4% to 9.4%, and the average recoveries ranged from 80.6% to 114.9%. Conclusion: ICP-MS method has a good effect on the determination of 22 elements in whole blood. The method is fast and simple, and can be used for clinical detection of multiple elements in whole blood.

Detection of egg white allergy in children by specific IgE microarray chemiluminescence immunoassay

BackgroundAllergen testing has emerged as a pivotal component in prevention and treatment strategies for allergic diseases among children and the utilization of specific IgE (sIgE) through a fully automated chemiluminescent microarray immunoassay (CLMIA) has emerged as a promising trend in the simultaneous detection of multiple allergenic components of children. MethodsThe accuracy and reliability of CLMIA were verified using children’s serum samples that concentrated on allergens. the allergens. The clinical diagnostic practicability of CLMIA was assessed through comprehensive evaluations including measurements of the limit of detection (LOD), intra-batch, and inter-batch precision, linearity analysis, the cross-contamination rate, and the concordance rate with the Phadia system. ResultsAfter the optimization process of CLMIA, the LODs for allergens were calculated to be below 0.01 kU/L, demonstrating the high sensitivity of CLMIA. All components exhibited good linearity within the range of 0.1–100.0 kU/L and the coefficient of determinations (R2 > 0.99). The data of intra-batch precision (<10 %) and inter-batch data (<15 %) illustrated the high reproducibility of CLMIA. The cross-contamination rates for allergens (<0.5 %) showed the high accuracy of CLMIA without interfering. The positive concordance rate between CLMIA and the Phadia system exceeds 90 % with a good negative concordance rate (>85 %) and the Kappa coefficients (>0.8), suggesting the close alignment of CLMIA and the Phadia system and showing the satisfactory clinical potential of CLMIA in children’s allergy disease. ConclusionsThe application of CLMIA has been promising in allergen testing, especially for detecting multiple allergenic components in children.

Hydrogen-bonded organic frameworks as stationary phase for open-tubular capillary electrochromatography

BackgroundCapillary electrochromatography (CEC) stationary phases have always been the focus of attention. The selection of excellent stationary phases are the key to realize separate of different compounds. Hydrogen-bonded organic frameworks (HOFs) are porous materials connected by hydrogen bonds between molecules, which have the advantages of renewable, high specific surface area and mild synthesis conditions. At present, HOFs are used in gas adsorption and storage, catalysis and drug delivery. Because of its unique advantages, HOFs have a bright future as CEC stationary phases. ResultsUsing melamine (MA) and 1,3,6,8-tetra (4-carboxylphenyl)pyrene (H4TBAPy) as reaction monomers, a HOFs named MA/PFC-1 was synthesized by solvent evaporation at room temperature. The inner wall of the capillary column was coated with MA/PFC-1 by chemical bonding. Sulfonamides were used as the target analytes. The effects of pH, phosphate buffer solution concentration, organic additive content and applied voltage on sulfonamides separation were investigated. The MA/PFC-1-coated capillary column had good resolution (>1.5) and reproducibility. The intra-day, inter-day, column-to-column, and inter-batch precision of the retention times were 0.03%–0.09%, 0.04%–0.09%, 0.03%–0.14% and 0.06%–0.09%, respectively. The intra-day, inter-day, column-to-column, and inter-batch precision of the peak areas were 0.11%–0.25%, 0.13%–0.20%, 0.12%–0.15% and 0.08%–0.15%, respectively. The MA/PFC-1-coated capillary column was run 150 consecutive times, and the results showed no noticeable change, which proved that this method had good stability. SignificanceThis work applied HOFs to CEC. The results show the that MA/PFC-1-coated capillary column has good separation performance. The MA/PFC-1-coated capillary column has been successfully applied to the determination of sulfamethoxazole in tablets, which has practical application value. To open up the application of HOFs in CEC and provide a new idea for developing new CEC stationary phases.

Determination of ivermectin in plasma and whole blood using LC-MS/MS.

Ivermectin is a widely used drug for the treatment of helminthiasis and filariasis worldwide, and it has also shown promise for malaria elimination through its potent mosquito-lethal activity. The objective of this study was to develop and validate a high-throughput and sensitive method to quantify ivermectin in plasma and whole blood samples, using automated sample extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Phospholipids were removed in patient whole blood (100 µl) and plasma (100 µl) samples using a 96-well plate Hybrid-solid phase extraction technique. Ivermectin and its isotope-labelled internal standard (ivermectin-D2) were separated on an Agilent Poroshell 120 EC-C18 50mm × 3.0mm I.D. 2.7µm, using a mobile phase of acetonitrile: ammonium formate 2 mM containing 0.5% formic acid (90: 10, v/v). Detection was performed using a triple quadrupole mass spectrometer in the positive ionization mode. The method was validated in the concentration range 0.970 - 384 ng/ml in both plasma and whole blood matrices. Intra- and inter-batch precisions during the validation were below 15%. There was no carryover or matrix effects detected. Ivermectin is a stable compound and results showed no degradation in the different stability tests. The validated method proved to have high sensitivity and precision, good selectivity and to be suitable for clinical application or laboratory quantification of ivermectin in plasma or whole blood samples.

High Throughput LC-MS/MS Method for the Quantitation of Mefenamic Acid in Rat Plasma by Protein Precipitation Technique Using 96 Well Plate Format

An advanced and validated high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach has been established to accurately determine the concentration of mefenamic acid in rat plasma. This method utilizes mefenamic acid D4 as the internal standard (ISTD). The analyte and ISTD underwent protein precipitation in a 96-well plate format and were then separated on a BDS Hypersil C8 column (3 μm, 100 x 4.6 mm) using a precise isocratic mobile phase of 2 mM ammonium formate by 0.1% formic acid and acetonitrile (30:70 v/v). The detection was performed on a triple quadrupole mass spectrometer utilizing positive ionization consideration. The approach demonstrated a concentration range of 20.659 to 20067.772 ng/mL, thru relative regaining reaching from 69.1 to 74.3%. The inter-batch precision was excellent, with a coefficient of variation (%CV) of ≤ 7.8%. Additionally, the inter-batch accuracy at four different quality control-points ranged from 97.0 to 100.4%, demonstrating high levels of accuracy. This method has been thoroughly validated and is extremely specific, accurate, and precise. It is perfectly suited for high-throughput investigation of mefenamic acid in rat plasma, making it ideal for routine analysis.

UPLC-MS/MS determination of 71 neuropsychotropic drugs in human serum

In this study, a UPLC-MS/MS method was developed for the rapid detection of 71 neuropsychotropic drugs in human serum for drug concentration monitoring and toxicity screening. The analytes were separated from the biological matrix by protein precipitation using a methanol-acetonitrile solvent mixture. The chromatographic separation was performed on a Kromasil ClassicShell C18 column (2.1*50 mm, 2.5 μ m) with gradient elution using acetonitrile-0.2 % acetic acid and 10 mM ammonium acetate as the mobile phases (flow rate 0.4 mL/min, column temperature 40 °C, injection volume 5 μL). An electrospray ion source in both positive and negative ion modes with multiple ion monitoring was used. The total run time was 6 min. All compounds were quantified using the isotope internal standard method. Totally, 71 drugs were detected within their linear ranges with correlation coefficients greater than 0.990. The intra- and inter-batch precision relative standard deviations (RSDs) for the low, medium, and high concentration points were less than 15 %, with an accuracy of 90%–110 %. All compounds except Moclobemide N-oxindole are stabilised within 7 days. The relative matrix effect results for each analyte were within ±20 % of the requirements. The method is validated according to Clinical and Laboratory Standards Institute guidelines, easy to use, and has a low cost.

Determination of ivermectin in plasma and whole blood using LC-MS/MS

Background Ivermectin is the most widely used drug for the treatment of helminthiasis worldwide, and it has also shown promise for malaria elimination through its potent mosquito-lethal activity. The objective of this study was to develop and validate a high-throughput and sensitive method to quantify ivermectin in plasma and whole blood samples, using automated sample extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods Phospholipids were removed in patient whole blood (100 µl) and plasma (100 µl) samples using a 96-well plate Hybrid-solid phase extraction technique. Ivermectin and its isotope-labelled internal standard (ivermectin-D2) were separated on an Agilent Poroshell 120 EC-C18 50mm × 3.0mm I.D. 2.7µm, using a mobile phase of acetonitrile: ammonium formate 2 mM containing 0.5% formic acid (90: 10, v/v). Detection was performed using a triple quadrupole mass spectrometer in the positive ionization mode. Results The method was validated in the concentration range 0.970 - 384 ng/ml in both plasma and whole blood matrices. Intra- and inter-batch precisions during the validation were below 15%. There was no carryover or matrix effects detected. Ivermectin is a stable compound and results showed no degradation in the different stability tests. Conclusions The validated method proved to have high sensitivity and precision, good selectivity and to be suitable for clinical application or laboratory quantification of ivermectin in plasma or whole blood samples.

Rapid diagnosis of acute myocardial infarction through integrated microfluidic chips for detection of characteristic targets

Myoglobin (Myo), creatine kinase-MB (CKMB), and cardiac troponin I (cTnI) are crucial biomarkers for diagnosing acute myocardial infarction (AMI) The accurate and rapid detection of these three targets can greatly improve the prognosis of AMI patients. Herein, this study developed a microfluidic immunofluorescence method that can detect all three targets in 10–15 min. Ultrasonic atomization and spray technology are used to modify the surface of the injection-molded microfluidic chip (MFC), which effectively solves the problem of biological cross-linking and antibody immobilization on the MFC surface. In addition, it improves the hydrophilicity of the chip surface, thus enhancing fluid self-driving effect. The linear response towards Myo, CKMB and cTnI range from 5 ng/mL to 500 ng/mL, 1 ng/mL to 70 ng/mL, and 0.05 ng/mL to 30 ng/mL, respectively. The intra-batch precision is ≤ 10%, and the inter-batch precision is ≤ 15%. Furthermore, this method shows good consistency compared with the BECKMAN ACCESS2 chemiluminescent immunoanalyzer. The present work provides an AMI diagnostic method with high sensitivity, good repeatability, high accuracy and simple operation, which can satisfy the needs of clinical diagnosis, and shows promising application prospects.

Pharmacokinetics study of atracurium, dexmedetomidine, midazolam and 1-hydroxymidazolam in patients undergoing acute aortic dissection surgery.

An UPLC-MS/MS method was developed and validated for simultaneous determination of atracurium (ATC), dexmedetomidine (DEX), midazolam (MDZ) and 1-hydroxymidazolam (1-OH-MDZ) and the pharmacokinetics of ATC, DEX, MDZ and 1-OH-MDZ in patients undergoing aortic dissection surgery were investigated. The analytes were extracted by acetonitrile precipitation and separated on an Acquity UPLC BEH C18 column (2.1mm × 50mm, 1.7μm) with a mobile phase of acetonitrile-0.1% formic acid and a gradient mode. In the positive ion mode, the following mass transition pairs were monitored by multiple reaction monitoring (MRM) for the four analytes and IS: m/z 385.1→206.2 for ATC, m/z 201.2→95.1 for DEX, m/z 326.1→291.1 for MDZ, m/z 341.9→324.0 for 1-OH-MDZ, and 284.9→153.9 for diazepam (IS). Seven male patients undergoing aortic dissection surgery received general anesthesia and intravenous administration of ATC, DEX, and MDZ during the surgery. Venous blood was collected at different time points at the end of surgery and after surgery. The concentrations of ATC, DEX, MDZ, and 1-OH-MDZ were detected, and the pharmacokinetic parameters were calculated. The method showed good linearity for each analyte. The inter-batch precision ranged from 1.37% to 9.87% and the intra-batch precision ranged from 2.41% to 10.72%; the accuracy ranged from 94.33% to 104.51%. Finally, the matrix effect, extraction recovery and stability data met the FDA recommended acceptance criteria for validation of bioanalytical methods. The t1/2 of ATC, DEX, MDZ and 1-OH-MDZ was (6.74 ± 2.27) h, (9.55 ± 4.93) h, (10.17 ± 5.35) h, and (6.90 ± 2.38) h, the Cmax, of ATC, DEX, MDZ and 1-OH-MDZ was (1054.20 ± 202.37) ng/mL, (1.93 ± 1.07) ng/mL, (1256.57 ± 389.09) ng/mL, and (1034.39 ± 292.92) ng/mL in patients undergoing aortic dissection surgery, respectively. The developed UPLC-MS/MS method for simultaneous determination of ATC, DEX, MDZ and 1-OH-MDZ in patient plasma was accurate, reproducible, specific. After continuous administration of ATC, DEX, and MDZ to patients undergoing surgery for acute aortic dissection, the pharmacokinetics of ATC, DEX, MDZ and 1-OH-MDZ in patients undergoing aortic dissection surgery were studied.

Multiplexed Antibody Glycosylation Profiling Using Dual Enzyme Digestion and Liquid Chromatography-Triple Quadrupole Mass Spectrometry Method

Antibody glycosylation plays a crucial role in the humoral immune response by regulating effector functions and influencing the binding affinity to immune cell receptors. Previous studies have focused mainly on the immunoglobulin G (IgG) isotype owing to the analytical challenges associated with other isotypes. Thus, the development of a sensitive and accurate analytical platform is necessary to characterize antibody glycosylation across multiple isotypes. In this study, we have developed an analytical workflow using antibody-light-chain affinity beads to purify IgG, IgA, and IgM from 16 μL of human plasma. Dual enzymes, trypsin and Glu-C, were used during on-bead digestion to obtain enzymatic glycopeptides and protein-specific surrogate peptides. Ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry was used in order to determine the sensitivity and specificity. Our platform targets 95 glycopeptides across the IgG, IgA, and IgM isotypes, as well as eight surrogate peptides representing total IgG, four IgG classes, two IgA classes, and IgM. Four stable isotope-labeled internal standards were added after antibody purification to calibrate the preparation and instrumental bias during analysis. Calibration curves constructed using serially diluted plasma samples showed good curve fitting (R2 > 0.959). The intrabatch and interbatch precision for all the targets had relative standard deviation of less than 29.6%. This method was applied to 19 human plasma samples, and the glycosylation percentages were calculated, which were comparable to those reported in the literature. The developed method is sensitive and accurate for Ig glycosylation profiling. It can be used in clinical investigations, particularly for detailed humoral immune profiling.

Development and Validation a UPLC-MS/MS Method for Quantification of Pentoxifylline in Beagle Plasma: Application for Pharmacokinetic Study of Food Effect.

To develop an UPLC-MS/MS method for the quantitative analysis of pentoxifylline in beagle dog plasma and apply it to a pharmacokinetic study of food effect. Sample separation was achieved using a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 μm) with a gradient elution program in 5.5 min after a simple protein precipitation with methanol. Using the mobile phase that made up by 0.2% formic acid and 5mM ammonium formate water (A) and methanol (B). Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM). A randomized, single-dose, two-period crossover study was conducted insix fasted or fed beagles that received 400 mg pentoxifylline sustained-release tablets (Brand name: Shuanling™, CSPC Pharmaceutical Group). WinNonlin® software was used to calculate pharmacokinetic parameters. The linear calibration range was 2-1000 ng/mL (r2> 0.99). Both intra- and inter-batch precision were less than 6.27%, and the accuracy ranged from 88.65% to 97.18%. Pentoxifylline was readily absorbed in fasted and fed dogs administered a dose of 400 mg (tmax:1.54h vs 1.83h). Compared to the fasted group, the AUC0→t and Cmax in the fed group increased by 1.71-fold and 1.30-fold, respectively. In the fasted group, the AUC0→t and Cmax values were 4684.08 h•ng/mL and 2402.33 ng/mL, respectively. In the fed group, these values were 8027.75 h•ng/mL and 3119.67 ng/mL. The difference in AUC0-t between the fed and fasted group was statistically significant. The novel optimized UPLC-MS/MS assay is an effective tool for the determination of pentoxifylline and has been successfully applied in pharmacokinetic studies of pentoxifylline in beagle dogs. The administration of pentoxifylline sustained-release tablets with food significantly increased the area under the time curve, and it is recommended that they should be administered during or shortly after feeding.

Determination of tamsulosin in plasma of healthy Chinese male subjects by a novel and simple LC-MS/MS method and its application to pharmacokinetic studies

Tamsulosin, the first highly selective α1-adrenoceptor antagonist, is widely used for urination disorders caused by benign prostatic hyperplasia (BPH). The pharmacokinetics and safety of 0.2 mg tamsulosin hydrochloride sustained-release capsules were evaluated in 60 healthy Chinese male subjects under fasting and fed conditions in this study. A simple, sensitive, and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of tamsulosin in human plasma, which has been applied to pharmacokinetic study. The analyte and internal standard (tamsulosin-d5) were extracted by protein precipitation, and separated on a ZORBAX Eclipse XDB-C18 column (4.6 × 50 mm,1.8 µm; Agilent Tech) using a gradient elution with mobile phases methanol and 5 mM ammonium acetate. The linear range was 0.05-15.0 ng/mL. It showed good selectivity in normal, hyperlipidemic, and hemolyzed blank matrices. The CV (%) of intra-batch precision was <4.4% and the RE (%) of accuracy was in the range of −5.0%–6.7%; the CV (%) of inter-batch precision was <−5.8% and the RE (%) of accuracy was in the range of 1.2%-4.0%. The mean extraction recovery for the analyte was 102.1 ± 3.75% and for the IS was 102.2 ± 2.00%. Two formulations were considered bioequivalent under fasting and fed conditions, and the 90% confidence intervals for the geometric mean test/reference ratios were within the predetermined range of 80%-125%. A single oral dose of 0.2 mg tamsulosin hydrochloride sustained-release capsule was well-tolerated throughout the clinical trial, and no > Grade 1 adverse events (AEs) and serious AEs occurred during the trial.

Metal organic frameworks as advanced materials for the paper-based extraction of synthetic cannabinoids in oral fluids

In this manuscript, a paper-based device modified with metal-organic frameworks was applied for the extraction of synthetic cannabinoid receptor agonists (SCRAs) in oral fluids, taking profit of the several interaction mechanisms between MOF-analytes, followed by their quantification by LC-fluorescence detection. The resulting composite, named as NH2[email protected], was characterized by different techniques such as infrared, scanning electron microscopy, among others. The extraction procedure was optimized by using a full factorial design after an appropriate selection of the significant variables. Once the method was optimized, the analytical parameters were studied including liner range (LOQ-400 µg L−1), limit of detection (0.7 to 2.8 µg L−1) and intra- and inter-batch precision (<8 and <20%, expressed as RSD, respectively). Next, the accuracy of the method was assessed at three different concentration levels (25, 75 and 100 µg L−1), obtaining values comprised from 64 to 98%. Finally, the method was applied for the analysis of oral fluids (n=25) (15 positives and 10 negative samples) and sensitivity, specificity and accuracy (efficiency) of the methodology were calculated obtaining 80, 100 and 88%, respectively.

An HPLC-MS/MS method for determination of sulbactam in human plasma and its pharmacokinetic application in critically ill patients with augmented renal clearance.

A simple, rapid, and specific method has been developed and validated to measure sulbactam in human plasma using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The pharmacokinetic characteristics of sulbactam in critically ill patients with augmented renal clearance were investigated after the repeated administration of cefoperazone-sulbactam (3 g, q8, IV drip, combination ratio of 2:1). Sulbactam plasma concentration was determined using LC-MS/MS with tazobactam used as an internal standard (IS). The method was fully validated with a sensitivity of 0.20 μg/mL, the linear concentration was ranged from 0.20 to 30.0 μg/mL. The intra-batch precision (RSD%) was less than 4.9%, and the accuracy deviation (RE%) ranged from -9.9 to 1.0%; the inter-batch precision (RSD%) was less than 6.2%, and the accuracy deviation (RE%) ranged from -9.2% to 3.7%. The value of the mean matrix factor at the low and high quality control (QC) concentration was 96.8 and 101.0%, respectively. The extraction recovery for QCL and QCH of sulbactam were 92.5 and 87.5%, respectively. Plasma samples and clinical data were collected at 0 (pre dose), 0.25, 0.5, 1, 2, 3, 6, and 8 hours (post dose) from 11 critically ill patients. Pharmacokinetic parameters were determined by non-compartmental analysis (NCA) using Phoenix WinNonlin software. This method was successfully applied to study the pharmacokinetics of sulbactam for critically ill patients. The main pharmacokinetic parameters of sulbactam in augmented renal function and normal renal function groups were summarized as follows: half-life, 1.45 ± 0.66 and 1.72 ± 0.58 hours, area under the concentration-time curve from 0 to 8 hours, 59.1 ± 20.1 and 111.4 ± 23.2 μg × h/mL, drug plasma clearance at steady state, 18.9 ± 7.5 and 9.32 ± 2 .03 L/h, respectively. These results suggested that a higher dose of sulbactam should be used in critically ill patients with augmented renal clearance.

Three-dimensional fluorinated covalent organic frameworks coated capillary for the separation of fluoroquinolones by capillary electrochromatography

In this work, a three-dimensional fluorinated covalent organic frameworks (3D FCOFs) JUC-515 was synthesized from tetra(4-aminophenyl)methane (TAM) and 2,3,5,6-tetrafluoroterephthalol (TFA) by an ionic liquid method. JUC-515 was introduced into the capillary column and bonded to the inner wall of the capillary column by chemical bonding. Through a variety of characterization results, JUC-515 was successfully synthesized and introduced into the capillary column. The effects of buffer solution concentration, organic additive content and pH of the buffer solution on the separation of fluoroquinolones (FQs) were investigated in detail. The JUC-515-coated capillary column showed good resolution (>1.5) and reproducibility. The relative standard deviations (RSDs) of the retention time for intraday, interday, column-to-column and interbatch precision were less than 0.88%, 2.45%, 2.74% and 3.32%, respectively. The RSDs of the peak area for intraday, interday, column-to-column and interbatch precision were less than 3.79%, 4.31%, 3.33% and 5.62%, respectively. The JUC-515-coated capillary column could be used no less than 150 times. The results showed that the JUC-515-coated capillary column had good separation performance. In addition, by separating fluorinated β-phenylalanine analogs, β-phenylalanine and trifluoromethyl β-phenylalanine analogs, the separation mechanism based on fluorine interactions was discussed. In conclusion, JUC-515 had good potential as a stationary phase for capillary electrochromatography.

LC-MS/MS assay for the therapeutic drug monitoring of perampanel in children with drug-resistant epilepsy

AbstractPerampanel (PER) is the first clinically available selective antagonist of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor approved globally for the treatment of epilepsy. Studies have recently underlined the significant association between dose-exposure-effect-adverse events of PER in patients with epilepsy, so the therapeutic drug monitoring (TDM) of PER is critical in clinical practices, especially for pediatric patients with drug-resistant epilepsy. Due to several limits in previous published analytical methods, herein, we describe the development and validation of a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method for monitoring PER in human plasma samples. Protein precipitation method by acetonitrile containing PER-d5 as internal standard was applied for the sample clean-up. Formic acid (FA, 0.2 mM) in both aqueous water and acetonitrile were used as the mobile phases and the analyte was separated by an isocratic elution. Qualification and quantification were performed under positive electrospray ionization (ESI) mode using the m/z 350.3 → 219.1 and 355.3 → 220.0 ions pairs transitions for PER and PER-d5, respectively. Potential co-medicated anti-seizure medications (ASMs) have no interference to the analysis. Calibration curves were linear in the concentration range of 1.00–2,000 ng mL−1 for PER. The intra- and inter-batch precision, accuracy, recovery, dilution integrity, and stability of the method were all within the acceptable criteria and no matrix effect or carryover was found. This method was then successfully implemented on the TDM of PER in Chinese children with drug-resistant epilepsy. We firstly confirmed the apparent inter- and intra-individual PER concentration variabilities and potential drug-drug interactions between PER and several concomitant ASMs occurred in Chinese pediatric patients, which were also in line with previous studies in patients of other race.

UPLC-MS/MS method development and application to pharmacokinetic study in rats and dogs of Flonoltinib Maleat

Flonoltinib Maleate (FM) is a novel selective inhibitor of Janus kinase 2/FMS-like tyrosine kinase 3 (JAK2/FLT3). In this study, we developed an ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to measure the plasma concentrations of FM in rats and dogs for pharmacokinetic studies. For chromatographic separation, we used a BEH C18 column (2.1 × 50 mm, 1.7 μm particle size) in HPLC. The mobile phase A consisted of a water solution containing 0.1% formic acid (FA) and 2 mM NH4OAc, mixed with acetonitrile (ACN) (V:V = 95:5). The mobile phase B was a water solution containing 0.1% FA and 2 mM NH4OAc, mixed with ACN (V:V = 5:95), which was used for gradient elution. We used multiple reactive ion detection (MRM) mode and electrospray ionization positive (ESI+) mode for quantitative analysis. The standard curve was linear in the concentration range of 0.5 to 500 ng/ml in rat and dog plasma. The intra-batch and inter-batch precision (RSD%) of FM in rat and dog plasma was less than 15%. The intra-batch and inter-batch accuracy was 88.3–106.5% and 92.0–100.6% in rats, and 94.7–106.6% and 95.3–103.8% in dogs, respectively. The RSD (%) of matrix factors (MF) normalized to the internal standard (IS) of FM in rat and dog plasma was ≤5.6% and ≤3.0%, respectively. The extraction recovery and carryover were considered acceptable. When the sample concentration was higher than the upper limit of quantitation (ULOQ), the 10-fold dilution was reliable within the limits of acceptability. The UPLC-MS/MS method developed in this study was successfully applied in measuring the pharmacokinetic parameters of FM in rats and dogs after intravenous and oral administration, laying a foundation for the preclinical pharmacokinetic study of FM and providing a reference for clinical pharmacokinetic studies.

Assessment of In Silico and In Vitro Selpercatinib Metabolic Stability in Human Liver Microsomes Using a Validated LC-MS/MS Method.

Selpercatinib (SLP; brand name Retevmo®) is a selective and potent RE arranged during transfection (RET) inhibitor. On 21 September 2022, the FDA granted regular approval to SLP (Retevmo, Eli Lilly, and Company). It is considered the only and first RET inhibitor for adults with metastatic or locally advanced solid tumors with RET gene fusion. In the current experiment, a highly specific, sensitive, and fast liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantifying SLP in human liver microsomes (HLMs) was developed and applied to the metabolic stability evaluation of SLP. The LC-MS/MS method was validated following the bioanalytical methodology validation guidelines outlined by the FDA (linearity, selectivity, matrix effect, accuracy, precision, carryover, and extraction recovery). SLP was detected by a triple quadrupole detector (TQD) using a positive ESI source and multiple reaction monitoring (MRM) mode for mass spectrometric analysis and estimation of analytes ions. The IS-normalized matrix effect and extraction recovery were acceptable according to the FDA guidelines for the bioanalysis of SLP. The SLP calibration standards were linear from 1 to 3000 ng/mL HLMs matrix, with a regression equation (y = 1.7298x + 3.62941) and coefficient of variation (r2 = 0.9949). The intra-batch and inter-batch precision and accuracy of the developed LC-MS/MS method were -6.56-5.22% and 5.08-3.15%, respectively. SLP and filgotinib (FLG) (internal standard; IS) were chromatographically separated using a Luna 3 µm PFP (2) stationary phase (150 × 4.6 mm) with an isocratic mobile phase at 23 ± 1 °C. The limit of quantification (LOQ) was 0.78 ng/mL, revealing the LC-MS/MS method sensitivity. The intrinsic clearance and in vitro t1/2 (metabolic stability) of SLP in the HLMs matrix were 34 mL/min/kg and 23.82 min, respectively, which proposed an intermediate metabolic clearance rate of SLP, confirming the great value of this type of kinetic experiment for more accurate metabolic stability predictions. The literature review approved that the established LC-MS/MS method is the first developed and reported method for quantifying SLP metabolic stability.

Establishment of matrix metalloproteinase 3 time-resolved immunoassay and some potential clinical applications

AimTo develop a highly sensitive time-resolved fluorescence immunoassay (TRFIA) for the detection of serum matrix metalloproteinase-3 (MMP-3) and to assess MMP-3's clinical value in patients with colorectal cancer (CRC).st. MethodsMMP-3 levels were established using the double antibody sandwich technique. The MMP-3 TRFIA technique was developed and optimized, and its linearity, sensitivity, accuracy, specificity, and recovery were assessed. Then, serum concentrations in healthy individuals and patients with CRC were determined by MMP-3 TRFIA. ResultsThe linear range of MMP-3 TRFIA was 0.73–500 ng/mL. MMP-3 TRFIA had an intra-batch precision range of 2.16%–7.10% percent and an inter-batch precision range of 3.99%–11.21%. MMP-3, tumor-associated trypsinogen 2, and AFP had no cross reaction.The recovery is between 90% and 110%, and had no serum interference. Patients with CRC had serum MMP-3 levels (73.95 ± 78.43 ng/mL) that were considerably higher than those of healthy individuals (21.45 ± 11.12 ng/mL), and those with metastasis had serum MMP-3 levels (95.89 ± 76.21 ng/mL) that were considerably higher than those of patients without metastasis (52.74 ± 47.25 ng/mL). ConclusionsA highly sensitive MMP-3 TRFIA assay was successfully developed, and serum MMP-3 may be associated with CRC invasion and metastasis. Therefore, MMP-3 can be used in the auxiliary diagnosis of CRC.