This study aims to identify biotransformation products of vincristine, a plant alkaloid chemotherapy drug. A batch biotransformation experiment was set-up using activated sludge at two concentration levels with and without the addition of a carbon source. Sample analysis was performed on an ultra-high performance liquid chromatograph coupled to a high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometer. To identify molecular ions of vincristine transformation products and to propose molecular and chemical structures, we performed data-dependent acquisition experiments combining full-scan mass spectrometry data with product ion spectra. In addition, the use of non-commercial detection and prediction algorithms such as MZmine 2 and EAWAG-BBD Pathway Prediction System, was proven to be proficient for screening for transformation products in complex wastewater matrix total ion chromatograms. In this study, we found eleven vincristine transformation products, of which nine were tentatively identified.
COBISS.SI-ID: 30696231
Purpose. With the aim to determine effective therapeutic window of electrochemotherapy, we analyzed bleomycin pharmacokinetic parameters in elderly patients. Methods. In prospective clinical study in the treatment of tumors with electrochemotherapy, blood samples of patients older than 65 years were collected after the bolus intravenous injection of bleomycin (15,000 IU/m2). In serum samples, quantitative analysis was performed with liquid chromatography coupled to high-resolution mass spectrometry. Based on the data, the pharmacokinetic parameters of bleomycin elimination were determined. Results. Pharmacokinetic analysis of the data revealed a monophasic serum clearance curve, which demonstrates slow elimination of bleomycin, being less than 500 ml/min and a half-time of 30 min. Conclusions. Slow monophasic elimination of bleomycin from serum in elderly patients implies on the longer therapeutic window, from 8 to up to 40 min or even longer post bleomycin injection for electrochemotherapy. However, prolonged therapeutic bleomycin serum concentrations may also affect the possible adverse effects, such as lung fibrosis and extensive necrosis of tumors due to the uptake of toxic bleomycin concentrations into the tumors. This may imply on lowering of bleomycin dosage, in particular in the elderly patients.
COBISS.SI-ID: 32555993
Etoposide susceptibility to microbiological breakdown was studied in a batch biotransformation system, in the presence or absence of artificial wastewater containing nutrients, salts and activated sludge at two concentration levels. The primary focus of the present study was to study etoposide biotransformation products by ultra-high performance liquid chromatography coupled to high-resolution hybrid quadrupole-Orbitrap tandem mass spectrometry (MS/MS). Data-dependent experiments combining full-scan MS data with product ion spectra were acquired to identify the molecular ions of etoposide transformation products, to propose the molecular formulae and to elucidate their chemical structures. Due to the complexity of the matrix, visual inspection of the chromatograms showed no clear differences between the controls and the treated samples. Therefore, the software package MZmine was used to facilitate the identification of the transformation products and speed up the data analysis. In total, we propose five transformation products, among them four are described as etoposide transformation products for the first time. Even though the chemical structures of these new compounds cannot be confirmed due to the lack of standards, their molecular formulae can be used to target them in monitoring studies.
COBISS.SI-ID: 29521959
Bleomycin is a cytotoxic antibiotic available as a compost of structurally strongly related glycopeptides, which is in vivo found chelated with several metals. Its pharmacotherapy has merely been based on experimental dose – response data, whereas its biodistribution and pharmacokinetics remain fundamentally unknown. This is reasoned by an absence of a specific and sensitive mass spectrometry-based analytical method for its determination in biological tissues. We herein re-veal the results of our study on the mass spectrometric behavior of two main bleomycin fractions A2 and B2, including their metal complexes, particularly the predominant copper chelates. In the electrospray ion source bleomycin forms double charged species, where for the metal-free fraction A2 and its copper complex m/z 707.76 and m/z 707.21 are seen, respec-tively. Hence, the second isotopic ion of the chelate (m/z 707.71) nearly coincides with the first isotopic ion of the metal-free fraction. This phenomenon can only be followed by high resolution mass spectrometry, and is considered the plausible rea-son, why the attempts to determine bleomycin with mass spectrometry have been so scarce. The presented paper further describes a sensitive and selective liquid chromatography – mass spectrometry analytical method for determination of ble-omycin in serum and tumor tissues. This newly-developed method was employed for bleomycin pharmacokinetics studies in serum and tumors of laboratory animals. Additionally, the method was employed for determination of bleomycin pharma-cokinetic parameters in elderly patients in order to determine the effective therapeutic window of electrochemotherapy with bleomycin.
COBISS.SI-ID: 29600039
The aim of the present study was to identify the in vitro Phase I and Phase II metabolites of three new psychoactive substances: α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV), and methedrone, using human liver microsomes and human liver cytosol. Accurate-mass spectra of metabolites were obtained using liquid chromatography-quadrupole time-of-flight mass spectrometry. Six Phase I metabolites of α-PVP were identified, which were formed involving reduction, hydroxylation, and pyrrolidine ring opening reactions. The lactam compound was the major metabolite observed for α-PVP. Two glucuronidated metabolites of α-PVP, not reported in previous in vitro studies, were further identified. MDPV was transformed into 10 Phase I metabolites involving reduction, hydroxylation, and loss of the pyrrolidine ring. Also, six glucuronidated and two sulphated metabolites were detected. The major metabolite of MDPV was the catechol metabolite. Methedrone was transformed into five Phase I metabolites, involving N- and O-demethylation, hydroxylation, and reduction of the ketone group. Three metabolites of methedrone are reported for the first time. In addition, the contribution of individual human CYP enzymes in the formation of the detected metabolites was investigated.
COBISS.SI-ID: 28755495