A UPLC-MS/MS Method for Plasma Biological Monitoring of Nirmatrelvir and Ritonavir in the Context of SARS-CoV-2 Infection and Application to a Case.

Nirmatrelvir/ritonavir association has been authorized for conditional use in the treatment of COVID-19, especially in solid-organ transplant recipients who did not respond to vaccine and are still at high risk of severe disease. This combination remains at risk of drug interactions with immunosuppressants, so monitoring drug levels seems necessary. After a simple protein precipitation of plasma sample, analytes were analyzed using an ultrahigh performance liquid chromatography system coupled with tandem mass spectrometry in a positive ionization mode.

Urine biomonitoring of occupational exposure to methotrexate using a highly sensitive UHPLC-MS/MS method in MRM mode.

Methotrexate (MTX) is widely used as antineoplastic drug (AD) and as an immunosuppressive. As a result, many healthcare professionals are exposed to this drug which is classified as dangerous to handle due to its reproductive toxicity in humans. Since the 1990 s, cases of internal contamination of professionals handling this molecule have been reported in the literature and even recently MTX was detected in the urine of professionals.

Methoxpropamine (MXPr) in powder, urine and hair samples: Analytical characterization and metabolite identification of a new threat.

Methoxpropamine (MXPr) is an arylcyclohexylamine dissociative drug with structural similarities with 3-MeO-PCE, ketamine and deschloroketamine. MXPr was identified for the first time in Europe in October 2019 in Denmark and is considered a new psychoactive substance. We undertook the molecular identification and characterization of MXPr in urine, hair and powder samples.

A highly sensitive UHPLC-MS/MS method for urine biological monitoring of occupational exposure to anthracycline antineoplastic drugs and routine application.

Anthracycline antineoplastic drugs (doxorubicin, epirubicin, daunorubicin) are "hazardous drugs for handling" by healthcare professionals. To monitor their occupational exposure, a highly sensitive ESI-UHPLC-MS/MS method for the assay of anthracyclines in urine was developed. The urine extraction consisted of SPE extraction method.

What do you need to know about mass spectrometry? A brief guide for endocrinologists.

In routine hormonology, liquid chromatography mass spectrometry (LCMS) is now an established technique for androgen, urinary cortisol and metanephrine assay. It has the undeniable advantage of great analytical specificity, but with sensitivity that clearly depends on financial investment in a very high-end spectrometer. We describe the general principles of LCMS and the routine applications so far developed in hormonology.

High throughput routine determination of 17 tyrosine kinase inhibitors by LC-MS/MS.

Several studies have shown that therapeutic drug monitoring of tyrosine kinase inhibitors (TKI) can improve their benefit in cancer. An analytical tool has been developed in order to quantify 17 tyrosine kinase inhibitors and 2 metabolites in human plasma (afatinib, axitinib, bosutinib, crizotinib, dabrafenib, dasatinib, erlotinib, gefitinib, imatinib, lapatinib, nilotinib, ponatinib, regorafenib, regorafenib M2, regorafenib M5, ruxolitinib, sorafenib, sunitinib, vandetanib). Drugs were arranged in four groups, according to their plasma concentration range: 0.

Highly sensitive LC-MS/MS methods for urinary biological monitoring of occupational exposure to cyclophosphamide, ifosfamide, and methotrexate antineoplastic drugs and routine application.

Highly sensitive ESI-LC-MS/MS methods were developed for urinary biological monitoring of occupational exposure to cyclophosphamide (CP), ifosfamide (IF), and methotrexate (MTX), which are hazardous antineoplastic drugs frequently handled by healthcare professionals. Extraction methods consisted of liquid/liquid extraction for simultaneous urinary CP and IF assays, and of solid phase extraction for the urinary MTX assay. A good linearity (r2>0.

Urinary glucocorticoid metabolites: biomarkers to classify adrenal incidentalomas?

Objective: Total urinary cortisol metabolites represent cortisol production and metabolism. We hypothesized that to assay metabolites could add some information to the one provided by a sole cortisol assay.

Design And Patients: We set up an inexpensive multiplex mass spectrometry assay to quantify cortisol metabolites.

Effects of rabeprazole on the antiplatelet effects and pharmacokinetics of clopidogrel in healthy volunteers.

Background: Several studies have suggested that proton-pump inhibitors (PPIs), mostly omeprazole, interact with clopidogrel efficacy by inhibiting the formation of its active metabolite via CYP2C19 inhibition. Whether this occurs with all PPIs is a matter of debate. As rabeprazole is a less potent CYP2C19 inhibitor than other PPIs, we studied the interaction between rabeprazole and the antiplatelet actions and pharmacokinetics of clopidogrel.

Simultaneous determination of nine tyrosine kinase inhibitors by 96-well solid-phase extraction and ultra performance LC/MS-MS.

Background: Tyrosine Kinase Inhibitors (TKIs) are a class of targeted drugs for the treatment of malignant pathologies. The metabolic profile of these drugs can result in great interindividual variability, thus therapeutic drug monitoring (TDM) is of importance. Here, a rapid and specific method for quantification of nine TKIs in plasma samples is described.

Trough imatinib plasma levels are associated with both cytogenetic and molecular responses to standard-dose imatinib in chronic myeloid leukemia.

Using high-performance liquid chromatography-tandem mass spectrometry, we assessed trough imatinib plasma levels in 68 patients with chronic myeloid leukemia (CML) who responded or not to standard-dose imatinib, after at least 12 months' treatment. Mean trough imatinib plasma levels were significantly higher in the group with complete cytogenetic response (56 patients) than in the group without (12 patients; P = .03) and higher in the group with major molecular response (MMR) than in the group without (34 patients [1452 +/- 649 ng/mL] versus 34 patients [869 +/- 427 ng/mL]; P < .

Fully automated analytical method for mycophenolic acid quantification in human plasma using on-line solid phase extraction and high performance liquid chromatography with diode array detection.

We have developed a new fully automated method for mycophenolic (MPA) acid quantification in plasma to optimize therapeutic drug monitoring of tranplant patients. This method involved solid-phase extraction on disposable extraction cartridges and reversed-phase high-performance liquid chromatography with diode array detection. Solid-phase extraction was performed automatically by an automated sample with extraction catridges system.

Quantification of imatinib in human plasma by high-performance liquid chromatography-tandem mass spectrometry.

Imatinib, also known as Gleevec or Glivec, is a selective tyrosine kinase inhibitor currently used for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (CML) and for other malignant pathologies. We have developed a LC-MS-MS [corrected] method that could be used for imatinib therapeutic drug monitoring in plasma. After a liquid-liquid extraction, the imatinib and its deuterated internal standard were eluted on an XTerra RP18 column with a gradient of acetonitrile-ammonium formiate buffer 4 mmol/L, pH 3.

Determination of moxifloxacin in growth media by high-performance liquid chromatography.

A direct injection high-performance liquid chromatographic method with column switching has been developed to determine moxifloxacin in Mueller-Hinton broth. A LiChrocart 4-4 pre-column filled with a LiChrospher 100 RP 18, 5 microm and a 150 x 4.6 mm I.

Pharmacokinetic population study to describe cefepime lung concentrations.

Pharmacokinetic parameters of cefepime in 2 g plasma and lung tissue bid over 3 days to achieve the steady-state was studied in 16 patients (15 male, one female) subjected to lung surgery for bronchial epithelioma. The aims of this study were firstly to quantify cefepime lung diffusion with cefepime lung concentrations in comparison with cefepime serum concentrations, and secondly to estimate population pharmacokinetic parameters of cefepime in lung tissue using NONMEM. The mean characteristics of patients were: age, 60 years (range, 51-69 years), weight, 73 kg (range, 62-87 kg) and creatinine clearance, 77 ml/min (range, 62-92 ml/min).

New approach for accurate simulation of human pharmacokinetics in an in vitro pharmacodynamic model: application to ciprofloxacin.

An in vitro pharmacodynamic model using a disposable dialyser unit and computer-controlled devices was developed. Feedback control of peristaltic pump flow rates is used to maintain constant flow rates, thus avoiding the problem of the modification of the physical properties of the tubing that generally occurs. Fast equilibrium is obtained with capillaries, which allows simulation of the same kinetic profile in the central and the peripheral compartments.

Determination of moxifloxacin (BAY 12-8039) in plasma and lung tissue by high-performance liquid chromatography with ultraviolet detection using a fully automated extraction method with a new polymeric cartridge.

The aim of this study was to develop a high-performance liquid chromatographic (HPLC) assay for the determination of moxifloxacin in human plasma and lung tissue. The assay was based on HPLC with a Supelcosil ABZ+ column and ultraviolet detection set at a wavelength of 296 nm. The extraction procedure was characterized by a fully automated liquid-solid extraction using an OASIS column for the solid phase.

Determination of cefepime and cefpirome in human serum by high-performance liquid chromatography using an ultrafiltration for antibiotics serum extraction.

The aim of this study was to describe a high-performance liquid chromatography (HPLC) assay for the determination of cefepime and cefpirome in human serum without changing chromatographic conditions. The assay consisted to measure cefepime and cefpirome which were unbound to proteins having a molecular mass of 10,000 or more by ultrafiltration followed by HPLC with a Supelcosil ABZ+ column and UV detection at a wavelength of 263 nm. The assay was been found to be linear and has been validated over the concentration range 200 to 0.

Pharmacokinetics of isepamicin during continuous venovenous hemodiafiltration.

The objective of this study was to analyze the pharmacokinetics of isepamicin during continuous venovenous hemodiafiltration. Six patients received 15 mg of isepamicin per kg of body weight. The mean isepamicin concentration peak in serum was 62.

Determination of phosphonoformate (foscarnet) in calf and human serum by automated solid-phase extraction and high-performance liquid chromatography with amperometric detection.

An isocratic high-performance liquid chromatographic method with automated solid-phase extraction has been developed to determine foscarnet in calf and human serums. Extraction was performed with an anion exchanger, SAX, from which the analyte was eluted with a 50 mM potassium pyrophosphate buffer, pH 8.4.

Simultaneous determination of ritonavir and saquinavir, two human immunodeficiency virus protease inhibitors, in human serum by high-performance liquid chromatography.

The aim of this study was to describe an high-performance liquid chromatographic assay for the simultaneous determination of two HIV protease inhibitors, saquinavir and ritonavir, in human serum. The method involved extraction of ritonavir and saquinavir from serum with the aid of solid-phase extraction C18 cartridges followed by high-performance liquid chromatography with a C8 column and ultraviolet detection set at a wavelength of 240 nm. The assay was linear and has been validated over the concentrations range of 0.

Fully automated high-performance liquid chromatography of ciprofloxacin with direct injection of plasma and Mueller-Hinton broth for pharmacokinetic/pharmacodynamic studies.

An isocratic high-performance liquid chromatographic method with column switching and direct injection has been developed to determine ciprofloxacin in plasma and Mueller-Hinton broth. An on-line dilution of the sample was performed with a loading mobile phase consisting of 173 mM phosphoric acid. The analyte was retained on a LiChrocart 4-4 precolumn filled with a LiChrospher 100 RP18, 5 microm.

[Transplacental passage of epirubicin].

We studied the transplacental transfer of epirubicin, an anthracycline used for the treatment of different neoplastic disorders, in particular breast cancers, by in vitro perfusion of term human placenta. Placenta from women with uncomplicated pregnancy were collected immediately after vaginal delivery and put into 37 degrees C thermostated hood. Perfusion of foetal surface of the placenta by modified Earle's solution was started immediately after catheterisation at a flow rate of 6 ml/min and then so was the perfusion of the intervillous space at the rate of 12 ml/min.

Sensitive high-performance liquid chromatographic method for the determination of labetalol diastereoisomers in plasma samples without derivatization.

A direct high-performance liquid chromatographic assay for the determination of labetalol diastereoisomers in plasma without derivatization was developed. Baseline resolution of diastereoisomers was accomplished on a C18 bonded reversed-phase polymeric column with a basic (pH 11.5) mobile phase and isocratic elution.