Simultaneous determination of fluoxetine, venlafaxine, vortioxetine and their active metabolites in human plasma by LC-MS/MS using one-step sample preparation procedure

Revealing Pharmacokinetic Interactions of Tramadol, Tapentadol, and Venlafaxine: A Cutting-Edge Liquid Chromatography-Tandem Mass Spectrometry Analytical Approach in Rat Plasma

The detection and quantification of opioid analgesics adulterated with serotonin reuptake inhibitors are critical in forensic toxicology due to their significant clinical and legal implications. This study focuses on developing and validating a highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of tramadol (TMD), tapentadol (TAP), and venlafaxine (VEN) in small volumes of rat plasma. The method employs a straightforward single-step protein precipitation technique for sample pretreatment. Utilizing a Shim-pack Velox SP-C18 column (2.7 μm, 2.1 × 150 mm, Shimadzu, Japan), a 12 min gradient elution was performed with a mobile phase of 0.1% formic acid in water (solvent A) and acetonitrile (solvent B). Detection and quantification were achieved in multiple-reaction-monitoring mode, with ion transitions of m/z 264.3 → 58.1 for TMD, m/z 222.3 → 107.1 for TAP, m/z 278.2 → 58.2 for VEN, and m/z 195.5 → 138.1 for caffeine, which served as the internal standard (IS). The method exhibited excellent linearity, with concentration ranges of 1-500 ng/mL for TMD (r 2 = 0.9981), 1-1000 ng/mL for TAP (r 2 = 0.9972), and 1-900 ng/mL for VEN (r 2 = 0.9987) in rat plasma using only 50 μL of sample. This validated method was applied to a pharmacokinetic interaction study, revealing significant drug interactions: the maximum observed plasma concentration (C max) and area under the curve (AUC) for both TMD and VEN decreased. For TMD, C max decreased by 2.58-fold from 276.25 to 106.99, and AUC0-t decreased by 1.4-fold from 3005.8 to 2159.3. For VEN, C max decreased by 2.51-fold from 494 to 191, and AUC0-t decreased by 2.3-fold from 4988 to 2114. However, for TAP, C max increased by 3.4-fold from 138.54 to 471.85, and AUC0-t increased by 2.66-fold from 1060.1 to 2826.8. The concurrent administration likely creates metabolic competition at CYP2D6 and UDP glycosyltransferase enzyme sites, affecting the pharmacokinetic parameters. These findings underscore the importance of further studies to monitor the simultaneous presence of these drugs and their metabolites in plasma, especially when coadministration occurs unintentionally.

Carbon-Based Nanomaterials 4.0

Research on carbon-based nanomaterials, such as carbon nanotubes and graphene and its derivatives, has experienced exponential development in recent years [...].

A high-throughput LC-MS/MS method for simultaneous determination of isoniazid, ethambutol and pyrazinamide in human plasma

RATIONALE

Tuberculosis (TB) remains a challenging global infectious disease, mainly affecting the lungs. First-line anti-TB drugs play a crucial role in slowing down the rapid spread of TB. In addition, the patient might benefit from therapeutic drug monitoring since it has become an accepted clinical tool for optimizing TB treatment.

METHODS

A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to monitor the plasma level of isoniazid, ethambutol and pyrazinamide in plasma samples. A one-step extraction procedure using an Ostro™ plate was applied, and extracts were analyzed by gradient elution followed by detection on a mass spectrometer by multiple reaction monitoring mode.

RESULTS

The analytes were separated within 4.2 min and over the concentration range of 0.2-10 μg/ml for isoniazid and ethambutol and 1-65 μg/ml for pyrazinamide. The method was successfully validated according to the European Medicine Agency guideline for the selectivity, linearity and lower limit of detection, precision and accuracy, matrix effect, extraction recovery, carryover, dilution integrity and stability, and applied for quantification of analytes in clinical samples from TB patients.

CONCLUSIONS

The presented method allows sensitive and reproducible determination of selected anti-TB drugs with advantages such as low sample volume requirement, short run time of analysis, one-step sample preparation procedure with capabilities for phospholipids removal, and a low quantification limit as well as a high degree of selectivity.

Use of Hierarchical Carbon Nanofibers Decorated with NiCo Nanoparticles for Highly Sensitive Vortioxetine Determination

A new voltammetry method for the highly sensitive antidepressant drug vortioxetine (VOR) is presented using glassy carbon electrodes modified with hierarchical carbon nanofibers with NiCo nanoparticles (eCNF/CNT/NiCo-GCE). The electrochemical behavior of VOR was investigated by cyclic voltammetry, which indicates that its oxidation is an adsorption-controlled process with the exchange of two electrons and one proton. The effects of various factors on the VOR peak, such as supporting electrolyte type, preconcentration time, and potential, or influence of interferents, were tested using the square wave voltammetry technique (SWV). The linear voltametric response for the analyte was obtained in the concentration range from 0.01·10-6 to 3.0·10-6 mol L-1 with the detection limit of 1.55·10-9 mol L-1 for a preconcentration time of 60 s. The proposed method was successfully applied for highly sensitive VOR determination in complex matrices such as tablets, urine, and plasma with good recovery parameter.

Determination of 12 anti-obesity drugs in human plasma by a 96-well protein precipitation plate using HPLC-MS

An analytical method was developed and validated for the simultaneous determination of 12 anti-obesity drugs (methylephedrine (MER), amphetamine (AMP), fenfluramine (FEN), bupropion (BUP), fluoxetine (FLU), sibutramine (SIBU), bisacodyl (BISA), bumetanide (BUM), lovastatin (LOVA), simvastatin (SIM), rimonabant (RIMO), and fenofibrate (FENO)) in human plasma by a 96-well protein precipitation plate combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). The 96-well protein precipitation plate was chosen for simultaneous pretreatment of large sample volumes, making the whole process more efficient and faster. Drugs were separated on an Agilent Poroshell 120 EC-C18 column, and detected by MS/MS under multiple reaction monitoring (MRM) mode. The developed method was validated in terms of linearity, matrix effect, accuracy and precision. A good linearity was obtained in the range of 0.1-20.0 ng mL-1 for fenfluramine, bupropion, fluoxetine, sibutramine, bisacodyl, and rimonabant; and 0.5-20.0 ng mL-1 for methylephedrine, amphetamine, bumetanide, lovastatin, simvastatin, and fenofibrate with a correlation coefficient above 0.995. The method was fully validated with an acceptable accuracy of 75.63-108.21%, matrix effect of 80.41-117.71% except for fenofibrate (76.07% at low concentration levels), and precision of 0.32-13.12%. Owing to the advantages of simple operation, high accuracy and sensitivity, this method is suitable for the rapid and simultaneous detection of 12 anti-obesity drugs in human plasma, providing support for clinically monitoring the development of adverse reactions and guiding the rational and appropriate use of weight-loss drugs for obese people.

Status and strategies of college English teaching using adaptive deep learning from the perspective of multiculturalism

The aim is to deeply understand the current situation of College English Teaching (CET). By consulting the theories of Deep Learning (DL) and Edge Computing (EC), this work designs a Questionnaire Survey (QS) to understand the current situation of college English learning and teaching. Then, Adaptive Deep Learning (ADL) and EC are introduced into CET. Finally, the corresponding conclusions and suggestions are drawn. Specifically, the purpose and time of college students’ vocabulary learning are investigated. The results suggest that students’ English vocabulary learning is shallow. They have not really mastered the meaning and usage of vocabulary. Simultaneously, teachers’ vocabulary teaching methods are analyzed from three aspects: root affixes, vocabulary collocation, or repeated reading and memory. The teaching method is excellent from the teacher’s perspective but far from perfect from the students’ perspective. Introducing ADL and EC into CET enhances students’ class concentration time, homework submission efficiency, and academic performance. More than half of the students believe that the new teaching method introducing ADL and EC can make them more confident and motivated in English learning. Therefore, it has great reference significance for applying ADL and EC in CET.

LC-MS/MS determination of dutasteride and its major metabolites in human plasma

Dutasteride is a specific and selective inhibitor of both 5α-reductase isoforms used mainly in benign prostatic hyperplasia and lower urinary tract symptoms. Although the drug is extensively metabolized in humans, data on the concentrations of its main metabolites are lacking. There is also a lack of data on dutasteride stability in frozen plasma samples. Our method was used to determine dutasteride and its active metabolites: 4'-hydroxydutasteride, 6β-hydroxydutasteride, and 1,2-dihydrodutasteride in plasma after a single administration of 0.5 mg of dutasteride. We also assessed the long-term stability (two years in the freezer) of dutasteride in clinical samples. The developed method covered the range of 0.1-3.5 ng/mL for dutasteride and 0.08-1.2 ng/mL for 1,2-dihydrodutasteride, 4'-hydroxydutasteride, 6β-hydroxydutasteride. It was proved to be reliable as it met all validation criteria required by the European Medicine Agency for bioanalytical methods. 4'-hydroxydutasteride and 1,2-dihydrodutasteride concentrations in plasma were higher than 6β-hydroxydutasteride. Dutasteride was stable in the freezer for up to 2 years in clinical samples. Thus within 1014 days of storage (below - 65 °C), samples can be reanalyzed without the risk of unreliable results.

Development of Sensitive and High-Throughput Liquid Chromatography-Tandem Mass Spectrometry Method for Quantification of Haloperidol in Human Plasma with Phospholipid Removal Pretreatment

Haloperidol, butyrophenone derivative, is a typical antipsychotic drug used in the treatment of schizophrenia, manic phase of bipolar disorder, and acute psychomotor agitations. According to the recent guidelines for therapeutic drug monitoring, it is strongly recommended to measure plasma level during the therapy with haloperidol. The objective of this study was to develop and validate a simple liquid chromatography-tandem mass spectrometry-based method to quantitate haloperidol in human plasma. After one-step extraction procedure using OSTROTM plate, gradient elution on Acquity UPLC BEH C18 (50 ×2.1mm, 1.7μm) column over 3.2 min was performed. The detection was conducted on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode in positive ionization mode with transitions at m/z 376.29 → 165.14 and m/z 380.28 → 169.17 for haloperidol and haloperidol-d4 (used as an internal standard), respectively. The method was fully validated to cover wide concentration range of 0.05-80 ng/mL in human plasma and meets the criteria for the selectivity, linearity and lower limit of detection, precision and accuracy, matrix effect, extraction recovery, carryover, dilution integrity and stability. The extraction recovery was nearly 100%, and no significant matrix effects were observed. Therefore, the method is applicable to routine therapeutic drug monitoring in patients' plasma.

Adolescent fluoxetine treatment mediates a persistent anxiety-like outcome in female C57BL/6 mice that is ameliorated by fluoxetine re-exposure in adulthood

The objective of this study was to evaluate whether juvenile fluoxetine (FLX) exposure induces long-term changes in baseline responses to anxiety-inducing environments, and if so, whether its re-exposure in adulthood would ameliorate this anxiety-like phenotype. An additional goal was to assess the impact of adolescent FLX pretreatment, and its re-exposure in adulthood, on serotonin transporters (5-HTT) and brain-derived-neurotrophic-factor (BDNF)-related signaling markers (TrkB-ERK1/2-CREB-proBDNF-mBDNF) within the hippocampus and prefrontal cortex. To do this, female C57BL/6 mice were exposed to FLX in drinking water during postnatal-days (PD) 35–49. After a 21-day washout-period (PD70), mice were either euthanized (tissue collection) or evaluated on anxiety-related tests (open field, light/dark box, elevated plus-maze). Juvenile FLX history resulted in a persistent avoidance-like profile, along with decreases in BDNF-signaling markers, but not 5-HTTs or TrkB receptors, within both brain regions. Interestingly, FLX re-exposure in adulthood reversed the enduring FLX-induced anxiety-related responses across all behavioral tasks, while restoring ERK2-CREB-proBDNF markers to control levels and increasing mBDNF within the prefrontal cortex, but not the hippocampus. Collectively, these results indicate that adolescent FLX history mediates neurobehavioral adaptations that endure into adulthood, which are indicative of a generalized anxiety-like phenotype, and that this persistent effect is ameliorated by later-life FLX re-exposure, in a prefrontal cortex-specific manner.

A novel stability-indicating method for determination of a new antidepressant effect of vortioxetine in a pharmaceutical formulation by using RP-HPLC

Background

A novel rapid, accurate, and stability-indicating reversed-phase high performance liquid chromatographic (RP-HPLC) and first derivative spectrophotometric determination were explained for the assay of vortioxetine (VRT) in bulk and pharmaceutical formulations. For RP-HPLC method, optimal separation and determination of VRT were achieved with a Waters Symmetry C18, (100 × 4.6 mm, 3.5 μm) analytical column using a mobile phase consisting of methanol:0.05 M potassium dihydrogen phosphate (pH:3.0 ± 0.05) (30:70, v/v) in isocratic mode with flow rate of 1.3 mL min−1. Injection volume was 20 μL. The maximum absorption wavelength of VRT is 225.0 nm; hence, 225.0 nm was studied as the detection wavelength and column at 50 °C temperature. The caffeine was used as the internal standard (IS). On the other hand, the first derivative spectrophotometric method for the analysis of vortioxetine was performed by measuring the amplitude at 251.7 and 272.6 nm.

Result

The HPLC method was found to be linear in the concentration ranges of 10.0-70.0 μg mL−1 with the coefficient value R2 of 0.9998, and the mean recovery value was 100.7%. Further stability studies were done through exposure of the analyte solutions to various stress conditions: acid, alkali hydrolysis, chemical oxidation, and exposure to UV radiation. For the first derivative spectrophotometric method, linearity was observed in the concentration range 6.0-30.0 μg mL−1 (for 237.7 nm R2 = 0.9999 and for 257.2 nm R2 = 0.9997).

Conclusion

The methods were validated in accordance with ICH guidelines with respect to linearity, accuracy, specificity, limit of detection, precision, and limit of quantification.

Therapeutic Drug Monitoring of Venlafaxine and Impact of Age, Gender, BMI, and Diagnosis

Depression is a common mental disorder affecting more than 264 million people in the world and 5.1% of the Slovak population. Although various antidepressant approaches have been used; still, about 40% of patients do not respond to a first-choice drug administration and one third of patients do not achieve total remission. Therapeutic drug monitoring (TDM) is a method used for quantification and interpreting the drug concentrations in plasma in order to optimize the pharmacotherapy. The aim of this study was to measure the plasma concentrations of venlafaxine, the fourth most prescribed antidepressant in Slovakia, as well as its active metabolite and interpret them with the relevant patients’ characteristics.

The study was of retrospective nature and 28 adult patients in total were included. The concentrations of venlafaxine and its active metabolite O-desmethylvenlafaxine (ODV) in plasma were quantified using the validated UHPLC-MS/MS method. The effects of potential influencing factors were evaluated by a multivariate linear regression model.

Only 39% of patients reached the venlafaxine active moiety concentrations within the recommended therapeutic range. Plasma concentrations were dependent on age, gender, and duration of the therapy. Venlafaxine metabolism expressed as a metabolite-to-parent concentrations ratio was influenced by a combination of age, gender, and body mass index (BMI). We did not observe any significant difference in plasma concentrations between the patients with a single and recurrent diagnosis of depression. Combining variables made an additive effect on plasma concentrations, for example, active moiety plasma concentrations were higher in older women. In contrast, drug metabolism was higher in older men and men with lower BMI. TDM of venlafaxine is recommended in clinical practice, especially in the elderly when beginning the pharmacotherapy.

Synthesis of three-dimensional nickel ferrite nanospheres decorated activated graphite nanoplatelets for electrochemical detection of vortioxetine with pharmacokinetic insights in human volunteers

An innovative electrochemical nanoprobe was developed for determination of vortioxetine (VORT), a serotonergic antidepressant drug, for the first time. The fabrication of the nanoprobe is based on decoration of a glassy carbon electrode with three-dimensional nickel ferrite nanospheres modified activated graphite nanoplatelets (3D NiFe₂O₄ NS/AGNP/GCE). The morphological characterization of the nanoprobe was carried out via scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDS), N₂-adsorption-desorption isotherm, and powder X-ray spectroscopy (PXRD). In addition, the electrochemical behavior of the nanoprobe was described using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). A well-defined and irreversible peak at 0.82 V was seen at the surface of 3D NiFe₂O₄ NS/AGNP/GCE. The proposed nanoprobe exhibited outstanding electro-catalytic activity towards VORT oxidation. Under the optimized conditions, the anodic oxidation currents were linearly proportional to VORT concentration at the working range 1.8-90 nM with a LOD of 0.55 nM. The nanoprobe was used to determine VORT in pharmaceutical tablets and human plasma samples. Satisfactory recoveries and RSD percentages were obtained in the range 103.8-107.7% (RSD% = 2.7-3.1%) and 101.4-105.3% (RSD % = 2.8-3.4%) for tablets and plasma samples, respectively. Moreover, the method was used to monitor VORT during a pharmacokinetic study in human volunteers with satisfactory results. The 3D NiFe₂O₄ NS/AGNP/GCE shows excellent sensitivity, reproducibility, and selectivity towards VORT detection. The proposed electrode could be utilized as simple, rapid, and inexpensive sensing tool for routine analysis and during pharmacokinetic/pharmacodynamic investigations. Graphical abstract.

Simultaneous quantification of vortioxetine, fluoxetine and their metabolites in rat plasma by UPLC-MS/MS

In this study, a specific and quick ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was fully developed and validated for simultaneous measurement of the rat plasma levels of vortioxetine (VOR), Lu AA34443 (the major metabolite of VOR), fluoxetine and its metabolite norfluoxetine with diazepam as the internal standard (IS). After a simple protein precipitation with acetonitrile for sample preparation, the separation of the analytes were performed on an Acquity UPLC BEH C18 (2.1 × 50 mm, 1.7 μm) column, with acetonitrile and 0.1% formic acid in water as mobile phase by gradient elution. The detection was achieved on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring mode via an electrospray ionization source. Good linearity was observed in the calibration curve for each analyte. The data of precision, accuracy, matrix effect, recovery and stability all conformed to the bioanalytical method validation of acceptance criteria of US Food and Drug Administration recommendations. The newly developed UPLC-MS/MS method allowed simultaneous quantification of VOR, fluoxetine and their metabolites for the first time and was successfully applied to a pharmacokinetic study in rats.