Matrix Effect Compensation in Small-Molecule Profiling for an LC-TOF Platform Using Multicomponent Postcolumn Infusion.

The possible presence of matrix effect is one of the main concerns in liquid chromatography-mass spectrometry (LC-MS)-driven bioanalysis due to its impact on the reliability of the obtained quantitative results. Here we propose an approach to correct for the matrix effect in LC-MS with electrospray ionization using postcolumn infusion of eight internal standards (PCI-IS). We applied this approach to a generic ultraperformance liquid chromatography-time-of-flight (UHPLC-TOF) platform developed for small-molecule profiling with a main focus on drugs.

Enhanced lipid isomer separation in human plasma using reversed-phase UPLC with ion-mobility/high-resolution MS detection.

An ultraperformance LC (UPLC) method for the separation of different lipid molecular species and lipid isomers using a stationary phase incorporating charged surface hybrid (CSH) technology is described. The resulting enhanced separation possibilities of the method are demonstrated using standards and human plasma extracts. Lipids were extracted from human plasma samples with the Bligh and Dyer method.

P-glycoprotein, multidrug-resistance associated protein 2, Cyp3a, and carboxylesterase affect the oral availability and metabolism of vinorelbine.

We investigated the interactions of the anticancer drug vinorelbine with drug efflux transporters and cytochrome P450 3A drug-metabolizing enzymes. Vinorelbine was transported by human multidrug-resistance associated protein (MRP) 2, and Mrp2 knockout mice displayed increased vinorelbine plasma exposure after oral administration, suggesting that Mrp2 limits the intestinal uptake of vinorelbine. Using P-glycoprotein (P-gp), Cyp3a-, and P-gp/Cyp3a knockout mice, we found that the absence of P-gp or Cyp3a resulted in increased vinorelbine plasma exposure, both after oral and intravenous administration.

Three spectroscopic techniques evaluated as a tool to study the effects of iodination of monoclonal antibodies, exemplified by rituximab.

Radioiodinated monoclonal antibodies have been used for radioimmunotherapeutic and radiodiagnostic purposes. Radioiodination of monoclonal antibodies may lead to deterioration of the immunoreactivity of the monoclonal antibody. Methods for the determination of the immunoreactivity, however, do not provide information about any structural changes of the radioconjugate which may influence the binding properties of the protein to the target antigen.

Malnourished Malawian patients presenting with large Wilms tumours have a decreased vincristine clearance rate.

Introduction: In developing countries, patients with a Wilms' tumour often present late with a high degree of malnutrition and large tumours. We investigated whether this affects vincristine pharmacokinetics.

Methods: Patients newly diagnosed with Wilms' tumour in Malawi and the UK were included.

Electrospray ionization quadrupole ion-mobility time-of-flight mass spectrometry as a tool to distinguish the lot-to-lot heterogeneity in N-glycosylation profile of the therapeutic monoclonal antibody trastuzumab.

Monoclonal antibodies are typically glycosylated at asparagine residues in the Fc domain, and glycosylation heterogeneity at the Fc sites is well known. This paper presents a method for rapid analysis of glycosylation profile of the therapeutic monoclonal antibody trastuzumab from different production batches using electrospray quadrupole ion-mobility time-of-flight mass spectrometry (ESI-Q-IM-TOF). The global glycosylation profile for each production batch was obtained by a fast LC-MS analysis, and comparisons of the glycoprofiles of trastuzumab from different lots were made based on the deconvoluted intact mass spectra.

Bioanalytical methods for the quantification of therapeutic monoclonal antibodies and their application in clinical pharmacokinetic studies.

Monoclonal antibodies (mAbs) are an upcoming group of therapeutic compounds used to treat various types of diseases. Currently more than 100 mAbs are in clinical development. To establish the pharmacokinetic (PK) properties of mAbs many (pre-)clinical studies are executed.

High-performance liquid chromatography coupled with mass spectrometry for the quantitative analysis of vinca-alkaloids in biological matrices: a concise survey from the literature.

The bioanalysis of vinca-alkaloids has been investigated extensively. High-performance liquid chromatography coupled to ultraviolet, fluorescence or electrochemical detection have been described. During recent years liquid chromatography coupled with mass spectrometry (LC-MS) has become the first choice for the quantitative bioanalysis of the vinca anticancer agents.

The bioanalysis of trastuzumab in human serum using precipitate-enhanced ellipsometry.

For the bioanalysis of therapeutic monoclonal antibodies in biological matrices, immunoassays--especially enzyme-linked immunosorbent assays (ELISAs)--are the most widely used techniques. Although ELISAs are very sensitive, the obtained sensitivity is not always sufficient. In this study, we have investigated the possibilities of performing a precipitate-enhanced immunoassay (PEIA) with ellipsometric detection for the bioanalysis of the therapeutic monoclonal antibody trastuzumab.

The bioanalysis of vinorelbine and 4-O-deacetylvinorelbine in human and mouse plasma using high-performance liquid chromatography coupled with heated electrospray ionization tandem mass-spectrometry.

A sensitive, specific and efficient high-performance liquid chromatography/tandem mass spectrometry assay for the simultaneous determination of vinorelbine and its metabolite 4-O-deacetylvinorelbine in human and mouse plasma is presented. Heated electrospray ionization was applied followed by tandem mass spectrometry. A 50 microL plasma aliquot was protein precipitated with acetonitrile-methanol (1:1, v/v) containing the internal standard vinorelbine-d3 and 20 microL volumes were injected onto the HPLC system.

The bioanalysis of the monoclonal antibody trastuzumab by high-performance liquid chromatography with fluorescence detection after immuno-affinity purification from human serum.

For the quantification of therapeutic monoclonal antibodies in biological specimens, enzyme-linked immunosorbent assay (ELISA) is the most widely used technique. ELISA's have some limitations and therefore alternative analytical techniques are being explored. In this study we describe the development of a bioanalytical assay using high-performance liquid chromatography (HPLC) coupled with fluorescence detection for the bioanalysis of the monoclonal antibody trastuzumab.

Development and validation of an enzyme-linked immunosorbent assay for the quantification of trastuzumab in human serum and plasma.

Trastuzumab, a humanized monoclonal antibody, is used for the treatment of breast cancer patients who overexpress the HER2 receptor. To optimize therapy, pharmacokinetic studies are necessary. The aim of this study was to develop an enzyme-linked immunosorbent assay (ELISA) for trastuzumab to support these pharmacokinetic studies.

Application of dried blood spots combined with high-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry for simultaneous quantification of vincristine and actinomycin-D.

A sensitive, specific and efficient high-performance liquid chromatography-tandem mass spectrometry assay for the simultaneous determination of vincristine and actinomycin-D in human dried blood spots is presented. Dried blood spots were punched out of a collection paper with a 0.25-in.

Validated assay for the simultaneous quantification of total vincristine and actinomycin-D concentrations in human EDTA plasma and of vincristine concentrations in human plasma ultrafiltrate by high-performance liquid chromatography coupled with tandem mass spectrometry.

A sensitive, specific and efficient high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) assay for the simultaneous determination of total vincristine and actinomycin-D concentrations in human plasma and an assay for the determination of unbound vincristine are presented. Electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and heated electrospray ionization (H-ESI) were tested as ionization interfaces. For reasons of robustness ESI was chosen followed by tandem mass spectrometry (ESI-MS/MS).

A sensitive assay for the quantitative analysis of vinorelbine in mouse and human EDTA plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry.

A sensitive, specific and fast high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) assay for the determination of vinorelbine in mouse and human plasma is presented. A 200 microL aliquot was extracted with solid-phase extraction (SPE) using Bond-Elut C(2) cartridges. Dried extracts were reconstituted in 100 microL 1 mM ammonium acetate pH 10.

Quantitative aspects of the analysis of the monoclonal antibody trastuzumab using high-performance liquid chromatography coupled with electrospray mass spectrometry.

The analytical possibilities of quantification of the intact monoclonal antibody trastuzumab by high-performance liquid chromatography coupled with electrospray mass spectrometry (HPLC-ESI-MS) were investigated. To clarify the results obtained by LC-MS, complementary experiments were performed using direct UV-spectrophotometry and high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). A polystyrene-divinylbenzene (POROS) column was applied with gradient elution using formic acid 0.