Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10-1000 ng/mL), with adequate accuracy (90.1-114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR.

• Klíčová slova
• Capillary electrophoresis, Desmethylriociguat, Determination, Mass spectrometry, Riociguat,
• MeSH
• elektroforéza kapilární metody   MeSH
• elektrolyty MeSH
• extrakce kapalina-kapalina MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• lidé MeSH
• limita detekce MeSH
• lineární modely MeSH
• pyrazoly krev   chemie   izolace a purifikace   farmakokinetika   MeSH
• pyrimidiny krev   chemie   izolace a purifikace   farmakokinetika   MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• elektrolyty MeSH
• pyrazoly MeSH
• pyrimidiny MeSH
• riociguat MeSH Prohlížeč

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.

• Klíčová slova
• Capillary electrophoresis, Dissociation constant, Fragmentation, Mass spectrometry, Riociguat,
• 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
• Názvy látek
• pyrazoly MeSH
• pyrimidiny MeSH
• riociguat MeSH Prohlížeč

OBJECTIVE: During the 2012 outbreak of mass methanol poisonings in the Czech Republic, ethanol, in the main, was used as an antidote. The complex pharmacokinetics of ethanol made it difficult to maintain the requisite 1000-1500 mg/L serum ethanol levels (S-EtOH). The aim of this study was to measure the fluctuations in S-EtOH during the treatment. METHODS: A prospective case series in 21 patients, median age 52 (27-79 years), 13 males and 8 females. Serum ethanol, methanol and formate were measured every 2-6 hours during the treatment. Follow-up clinical examination was carried out in 15/18 survivors. RESULTS: The majority of patients (17/21) were late presenters and on admission, almost half (10/21) had suffered a severe grade of intoxication according to the Poisoning Severity Score (PSS). The mean observation time was 90±20 h. The mean period of consistent maintenance of S-EtOH within the recommended therapeutic range lasted 28±7% of the total observation time. For 29±8% of the time, S-EtOH was >1500 mg/L with "peaks" of up to 3500 mg/L. For 44±10% of the observation time, S-EtOH was <1000 mg/L. The mean duration of sub-therapeutic concentration of S-EtOH and toxic serum levels of methanol >200 mg/L or formate >20 mg/L lasted 20±10% and 18±11% of the time of observation, respectively. Complications occurred in 14 (67%) of cases including significant fluctuations of S-EtOH in 9; aspiration pneumonia in 3 and delirium tremens in 2 cases. Other complications included sepsis, bleeding, acidosis rebound, intolerance and set clotting. The outcomes were: 11 survivors free of health impairment, 7 with sequelae and 3 deaths. There was no significant difference in mean duration of sub-therapeutic and supra-therapeutic concentrations of serum ethanol in patients who survived without sequelae and those with poor outcome (P > 0.05). CONCLUSION: Administration of ethanol according to the present guidelines of the AACT/EAPCCT is effective and relatively safe in the treatment of methanol poisoning during a mass outbreak(31). Physicians have to be most aware of fluctuations in serum ethanol at the end of short sessions of IHD and after changes in route from intravenous to oral. Rigorous monitoring of serum ethanol concentrations is pivotal for severely poisoned patients with PSS 3 and where there is suspected conversion of significant amounts of methanol to formic acid.

• Klíčová slova
• CNS sequelae, adverse events, antidote, ethanol, methanol poisoning, treatment outcome, variations in serum levels, visual sequelae,
• MeSH
• antidota aplikace a dávkování   farmakokinetika   MeSH
• dospělí MeSH
• ethanol aplikace a dávkování   krev   farmakokinetika   MeSH
• fomepizol MeSH
• kombinovaná farmakoterapie MeSH
• lidé středního věku MeSH
• lidé MeSH
• methanol otrava   MeSH
• prospektivní studie MeSH
• pyrazoly aplikace a dávkování   krev   farmakokinetika   MeSH
• senioři MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• antidota MeSH
• ethanol MeSH
• fomepizol MeSH
• methanol MeSH
• pyrazoly MeSH

A liquid chromatography-electrospray tandem mass spectrometry method was developed and validated to quantitate celecoxib in human plasma. The assay was based on protein precipitation with methanol and liquid chromatography on a C₁₈ column (55 mm × 2 mm, 3 μm), the mobile phase consisted of methanol-10 mM ammonium acetate (75:25, v/v). Quantification was performed by mass spectrometry in the multiple reaction monitoring mode with negative electrospray ionization at m/z 380→316 and 384→320 for celecoxib and the internal standard celecoxib-D₄, respectively. The lower limit of quantitation was 7.0 ng/ml using 0.1 ml of plasma and linearity was demonstrated up to 1800 ng/ml. Intra-assay and inter-assay precision expressed by relative standard deviation was less than 4% and inaccuracy did not exceed 6% at all levels. The assay was applied to the analysis of samples from a pharmacokinetic study.

• MeSH
• celekoxib MeSH
• dospělí MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• inhibitory cyklooxygenasy 2 krev   MeSH
• krevní plazma chemie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• pyrazoly krev   MeSH
• sulfonamidy krev   MeSH
• tandemová hmotnostní spektrometrie metody   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• Názvy látek
• celekoxib MeSH
• inhibitory cyklooxygenasy 2 MeSH
• pyrazoly MeSH
• sulfonamidy MeSH

An analytical method was worked out to determine Lonazolac in human plasma based on precipitation of human plasma with a precipitating agent and methanol. This deproteinized plasma was analyzed by liquid chromatography with the use of a reverse phase and fluorimetric detection. The described method is sufficiently sensitive (the limit of detection under 0.1 microgram/ml of plasma) and precise (error of the method = 9%). The precision of the method, recovery from the plasma (100 +/- 3%) and stability in frozen plasma (minimally one month) are presented. Application of the method in a comparison of the newly developed Czechoslovak preparation Lonazolac and the foreign preparation Irritren is shown. Results are documented by the course of the levels of both preparations in dependence on time and principal pharmacokinetic parameters derived from the one-compartmental model.

• MeSH
• antiflogistika nesteroidní krev   MeSH
• chromatografie kapalinová metody   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• pyrazoly krev   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antiflogistika nesteroidní MeSH
• lonazolac MeSH Prohlížeč
• pyrazoly MeSH

• MeSH
• aplikace orální MeSH
• čípky MeSH
• dospělí MeSH
• fenylbutazon aplikace a dávkování   krev   MeSH
• kinetika MeSH
• lidé středního věku MeSH
• lidé MeSH
• pyrazoly aplikace a dávkování   krev   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• čípky MeSH
• fenylbutazon MeSH
• pyrazoly MeSH

• MeSH
• dospělí MeSH
• fenylbutazon analogy a deriváty   krev   MeSH
• lidé MeSH
• pyrazoly krev   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• fenylbutazon MeSH
• pyrazoly MeSH

• MeSH
• antiflogistika krev   metabolismus   moč   MeSH
• časové faktory MeSH
• feces analýza   MeSH
• intestinální absorpce účinky léků   MeSH
• izotopy uhlíku MeSH
• ketony metabolismus   MeSH
• krysa rodu Rattus MeSH
• metabolická clearance MeSH
• pyrazoly krev   metabolismus   moč   MeSH
• žlučové ústrojí metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiflogistika MeSH
• izotopy uhlíku MeSH
• ketony MeSH
• pyrazoly MeSH

• MeSH
• absorpce MeSH
• fotometrie MeSH
• krysa rodu Rattus MeSH
• pyrazoly aplikace a dávkování   analýza   krev   moč   MeSH
• žluč analýza   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• pyrazoly MeSH