Czech Chemical Society Symposium Series

Úvod

Sat, 15 Mar 2025 00:00:00 +0100

Ambientní hmotnostní spektrometrie pro analýzu selektivních modulátorů androgenního receptoru

Jana Knytlová, Alžběta Nemeškalová, Michael Volný — Sat, 15 Mar 2025 00:00:00 +0100

Ambient ionization mass spectrometry (AMS) enables sample analysis in its native state with minimal preparation. This study explores the use of a commercial Sicrit® ion source, based on dielectric barrier discharge ionization, for detecting selective androgen receptor modulators (SARM) in dietary supplements, commonly abused for muscle mass enhancement. Tablets and capsules were dissolved in methanol and analyzed directly using the Sicrit® source coupled to an Orbitrap Exploris 120 mass spectrometer in positive mode. For confirmation, samples were also analyzed by LC-UV-MS. While LC-UV-MS provided superior quantitative analysis, AMS demonstrated strong qualitative agreement, indicating its potential for rapid screening of illegal anabolic substances in dietary supplements.

Využití kapalinové chromatografie při studiu stability a degradace farmaceuticky významných látek

Michael Skála, Tomáš Křížek — Sat, 15 Mar 2025 00:00:00 +0100

Nowadays, the determination of free radicals has become one of the main goals in chemical industry, especially in pharmaceutics, because of the reactivity of radicals and thus the formation of impurities and possibly inactive or toxic products resulting from reactions with active pharmaceutical ingredients. This work focuses on the determination of radicals contained in pharmaceutical excipients using high-performance liquid chromatography on reverse phase (RP-HPLC). As a desired result, we are looking for a radical scavenger that is able to undergo a defined reaction with the radical and linearly produce a quantifiable product. The stable radical molecule (4‑hydroxy-2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) is used as a standard of radical behavior. Firstly, the purity of the radical was verified for possible impurities by MS analysis, which showed a high purity of TEMPO. Secondly, the efficiency of several well-known scavengers was tested by reaction with TEMPO. While the reduced glutathione showed a very fast reaction with the radical, the predicted product (in this case oxidized glutathione) did not form linearly, and the subsequently performed MS analysis showed multiple reaction pathways, mostly explained by breakage of the peptide chain. Coumarin was used next in order, which showed no determinable reaction with the radical at all, even after increasing the temperature. At present, the main attention is focused on ascorbic acid and its oxidation product dehydroascorbic acid. We expect the scavenging mechanism to be very similar to that of reduced glutathione, however, the possibilities of side products are limited, the main issue at this point being the RP-HPLC separation of ascorbic and dehydroascorbic acid, respectively.

Využitie vsádzkovej injekčnej analýzy pri elektrochemickom stanovení warfarínu

Victória Žužičová, Vlastimil Vyskočil — Sat, 15 Mar 2025 00:00:00 +0100

In this work, the optimum conditions for the determination of warfarin sodium (WAR) by the technique of batch injection analysis with amperometric detection (BIA‑AD) on a screen-printed carbon electrode (SPCE) were sought in order to use the method for the determination of the content of the active substance in the dosage form. Optimization of the experimental conditions was carried out in a Britton-Robinson (BR) buffer medium at pH 7.0. The optimum determination parameters were found: a detection potential of +1.0 V, a dosing volume of 60 µL, and a dosing rate of 286.3 µL s⁻¹. The linear region of concentration dependence was determined in the range of 1.0×10⁻⁶ – 8.0×10⁻⁴ mol L⁻¹, and the limit of detection LOD = 7.5×10⁻⁷ mol L⁻¹ and the corresponding limit of quantification LOQ = 2.5×10⁻⁶ mol L⁻¹ were achieved. The developed method was applied for the determination of the active substance content in Warfarin Orion 5 mg tablets and was compared with UV-VIS absorption spectrophotometry. The recovery of the developed amperometric method against the analytical reference method was determined to be 104.2%. The BIA-AD in conjunction with the SPCE was demonstrated in this work to be a rapid, efficient, simple, and inexpensive method for the determination of substances in pharmaceutical samples.

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Sat, 15 Mar 2025 00:00:00 +0100