Fipronil is an insecticide that is not approved in the European Union in food. In 2017, fipronil was involved in a European health alert due to its presence in fresh hen eggs because of an illicit use in poultry farms, so reliable methods are needed to determine fipronil and its main metabolites in these matrixes. In this work, we report the first approach to the study of fipronil and two metabolites, fipronil-sulfone and fipronil-sulfide by CE. MEKC mode was employed using a solution of 50 mM ammonium perfluorooctanoate pH 9.0 with 10% (v/v) methanol as background electrolyte. The proposed method was combined with a simple sample treatment based on salting-out assisted LLE (SALLE) using acetonitrile as extraction solvent and ammonium sulfate as salt. The SALLE-MEKC-UV method allowed the simultaneous quantification of fipronil and fipronil-sulfone. Validation parameters yielded satisfactory results, with precision, expressed as relative SD, below 14% and recoveries higher than 83%. Limits of detection were 90 µg/kg for fipronil and 150 µg/kg for fipronil-sulfone, so in terms of sensitivity further studies of sample treatments allowing extra preconcentration or the use of more sensitive detection, such as MS, would be needed.
- MeSH
- acetonitrily MeSH
- chromatografie micelární elektrokinetická kapilární metody MeSH
- insekticidy MeSH
- kur domácí MeSH
- limita detekce MeSH
- lineární modely MeSH
- pyrazoly analýza MeSH
- reprodukovatelnost výsledků MeSH
- vejce analýza MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
New degradation impurities at m/z 327.15 and m/z 311.16 using gradient UHPLC method with UV detection and highly selective QDa mass detection were observed during the ruxolitinib hydrobromide (RUX.HBr) : excipient binary mixture degradation study. High mass resolution LC-MS and nuclear magnetic resonance (NMR) techniques were employed to identify and fully characterize the degradation compounds. The degradation impurities were unambiguously identified as (R)-4-amino-6-(1-(2-cyano-1-cyclopentylethyl)-1H-pyrazol-4-yl)pyrimidine-5-carboxylic acid and (R)-3-(4-(6-amino-5-formylpyrimidin-4-yl)-1H-pyrazol-1-yl)-3-cyclopentylpropanenitrile and mechanism of their formation was proposed. It has been confirmed that the degradation products are formed in mixtures of RUX.HBr with some excipients in the presence of oxygen. Based on the forced degradation study, the chemically stable of pharmaceutical formulations were prepared to eliminate the formation of these impurities.
- MeSH
- hmotnostní spektrometrie MeSH
- kontaminace léku MeSH
- kyslík chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- příprava léků MeSH
- pyrazoly analýza MeSH
- referenční standardy MeSH
- roztoky MeSH
- tablety analýza MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
Riociguat is a novel antihypertensive drug for the treatment of pulmonary hypertension. We present electrophoretic characterization, i.e. migration behavior of riociguat and metabolite M1 as support for optimized CZE/MS assay. Fundamental separation parameters, such as peak width, symmetry, and resolution are studied in a series of ammonium formate buffers within pH range 2.60-5.61. The narrow region of peak symmetry lies close to pH 4.0 for both analytes. Accordingly, the value of resolution maximizes in a background electrolyte adjusted to pH 4.10. Basic calibration parameters estimated from CZE experiments with absorption photometric and mass spectrometric detection of riociguat and metabolite M1 were evaluated. More than three orders lower LOD was achieved with high resolution mass spectrometric detection. The observed difference in the sensitivity of both detection techniques gives priority to the utilization of CZE/MS in practice. The values of dissociation constants of riociguat and metabolite M1, pKBH , were determined from CZE measurements in lithium formate and lithium acetate background electrolytes with constant ionic strength. The value of pKBH = 4.30 ± 0.02 for riociguat corresponds well to the value already presented in the literature. According to our observation, metabolite M1 behaves like a slightly stronger base with estimated pKBH = 4.40 ± 0.02.
- MeSH
- elektroforéza kapilární metody MeSH
- hmotnostní spektrometrie metody MeSH
- lidé MeSH
- limita detekce MeSH
- lineární modely MeSH
- pyrazoly analýza krev chemie metabolismus MeSH
- pyrimidiny analýza krev chemie metabolismus MeSH
- reprodukovatelnost výsledků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The effect of direct oral anticoagulants (DOACs) on laboratory tests dependent on the production of their targets, factor IIa and factor Xa (FXa), is a well-known problem and can cause both false positive and negative results. Therefore, the correct interpretation of tests performed in patients receiving DOACs is necessary to avoid misclassification and subsequent clinical consequences. However, even with significant experience, there are situations where it is not possible to assess the influence of some methods. Particularly important is the situation in the diagnosis of lupus anticoagulants using the dilute Russell viper venom timetest, which is based on direct FXa activation. A very promising solution to this situation is offered by the DOAC laboratory balancing procedure DOAC-Stop. For evaluating the effectiveness of this procedure, 60 (20 apixaban, 20 dabigatran, and 20 rivaroxaban) patients treated with DOACs were enrolled. All patient samples were analyzed for the presence of individual DOAC types and subsequently subjected to the DOAC-Stop procedure.We evaluated its effectiveness by our own high-performance liquid chromatography-coupled tandem mass spectrometrymethod, which simultaneously sets all high-sensitivity DOACs. Unlike coagulation tests based on the determination of the residual effects of DOACs on target enzymes, which is complicated by extensive interindividual variation, this methodology is highly specific and sensitive.The DOAC-Stop procedure eliminated dabigatran from 99.5%, rivaroxaban from 97.9%, and apixaban from 97.1% of participants in our group. Residual amounts did not exceed 2.7 ng/mL for dabigatran, 10.9 ng/mL for rivaroxaban, or 13.03 ng/mL for apixaban, which are safe values that do not affect either screening or special coagulation tests.
- MeSH
- antithrombiny MeSH
- chromatografie kapalinová metody MeSH
- dabigatran analýza farmakologie terapeutické užití MeSH
- hemokoagulace účinky léků MeSH
- inhibitory faktoru Xa analýza farmakologie terapeutické užití MeSH
- lidé MeSH
- lupusový inhibiční faktor koagulace krev MeSH
- metody MeSH
- pyrazoly analýza farmakologie terapeutické užití MeSH
- pyridony analýza farmakologie terapeutické užití MeSH
- rivaroxaban analýza farmakologie terapeutické užití MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
