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EN
Nowadays, chromatographic methods coupled with mass spectrometry are the most commonly used tools in metabolomics studies. These methods are currently being developed and various techniques and strategies are proposed for the profiling analysis of biological samples. However, the most important thing used to maximize the number of entities in the recorded profiles is the optimization of sample preparation procedure and the data acquisition method. Therefore, ultra high performance liquid chromatography coupled with accurate quadrupoletime- of-flight (Q-TOF) mass spectrometry was used for the comparison of urine metabolomic profiles obtained by the use of various spectral data acquisition methods. The most often used method of registration of metabolomics data acquisition – TOF (MS) was compared with the fast polarity switching MS and auto MS/MS methods with the use of multivariate chemometric analysis (PCA). In all the cases both ionization mode (positive and negative) were studied and the number of the identified compounds was compared. Additionally, various urine sample preparation procedures were tested and it was found that the addition of organic solvents to the sample noticeably reduces the number of entities in the registered profiles. It was also noticed that the auto MS/MS method is the least efficient way to register metabolomic profiles.
EN
The influence of ionising radiation on physicochemical properties of doripenem in solid state was studied. No changes for doripenem irradiated with a dose of 25 kGy, required to attain sterility, was observed by FT-IR and chromatographic methods, although the presence of free radicals (7.7*1017 radicals/g) was detected by EPR. The antibacterial activity of doripenem irradiated with a dose of 25 kGy was unchanged. Solid doripenem has proven to be very stable on irradiation, and irradiation has been found to be a suitable method for its sterilization.
EN
Ultra high-performance liquid chromatography (UHPLC) coupled with high-resolution quadrupole time-of-flight (Q-TOF) mass spectrometry was used for the preliminary photodegradation study of nine new generation psychotropic drugs. Based on the above method, two ionization sample modes — electrospray and atmospheric pressure chemical ionization were used for the registration of photodegradation profiles of the selected drugs. Multivariate chemometric analysis showed that electrospray ionization (ESI) method is more specific than atmospheric pressure chemical ionization (APCI) in high-resolution mass spectrometry (HR-MS) analysis of the analyzed psychotropic drugs. It was noticed that, with the use of ESI method, more potential photodegradation products can be identified and lower limits of its detection can be obtained.
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Content available THE RADIOSTABILITY OF BETAMIPRON IN THE SOLID STATE
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EN
The influence of ionising radiation on physicochemical properties of betamipron in solid state was studied. No changes for betamipron irradiated with a dose of 25 kGy, required to attain sterility, was observed by spectroscopic and chromatographic methods. Solid betamipron has proven to be very stable on irradiation, and irradiation has been found to be a suitable method for its sterilization.
5
Content available remote A study of photodegradation of quetiapine by the use of LC-MS/MS method
100%
Open Chemistry
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2012
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tom 10
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nr 1
232-240
EN
Photodegradation of quetiapine under UVC irradiation in methanol solution was investigated and structural elucidation of its photodegradation products was performed with the use of the reversed phase UHPLC system coupled with accurate mass hybrid ESI-Q-TOF mass spectrometer. During one run all essential data for the determination of photodegradation kinetics and for the structural elucidation of the products was collected with the use of auto MS/MS mode. Five degradation products were found and their masses and formulas were obtained with high accuracy (0.26–5.02 ppm). For all the analyzed compounds, MS/MS fragmentation spectra were also obtained allowing structural elucidation of the unknown degradation products and indicating photodegradation pathways of quetiapine. The main photodegradation product was identified as 2-[2-[4-(5-oxidodibenzo[b,f][1,4]thiazepin-11-yl)-1-piperazinyl]ethoxy]-ethanol and the photodegradation reaction yields the first-order kinetics with the rate constant k = 0.1094 h−1.
EN
One of the best sterilization methods for chemically unstable drugs, such as carbapenems, is irradiation. The chemical and physical properties of radiosterilized imipenem and cilastatin were analyzed using spectrophotometric and chromatographic methods. Unstable free radicals were presented in samples after irradiation; their mean lifetime was 142±64 h. The antibacterial activity of cefozopran hydrochloride irradiated with a dose of 25 kGy changed for Klebsiella pneumoniae and Escherichia coli. Imipenem and cilastatin in the solid state are not resistant to radiation sterilization; therefore, this method cannot be used for sterilization of this compound.
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EN
The influence of ionizing radiation on the physicochemical properties of panipenem in solid state was studied. In the first part of our studies, we evaluated the possibility of applying radiosterilization to obtain sterile panipenem. Spectroscopic (FT-IR, Raman), chromatography (HPLC and HPLC-MS) and X-ray powder diffraction (XRPD) studies have shown that irradiation of ertapenem with the 25 kGy, the dose required to achieve sterility, does not change the physicochemical properties of the studied compound. The antimicrobial activity of panipenem irradiated with the dose of 25 kGy was reduced for three species. It was confirmed that the decrease in antimicrobial activity might be related to isomerization of panipenem.
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