Vít Zvoníček

Mr. Vít Zvoníček


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 January 2025 in Pharmaceutics
Verified
Journal Article
Open access
PDF file
SRSreela Ramesh
Sreela Ramesh
VZVít Zvoníček
Vít Zvoníček
DPDaniel Pěček
Daniel Pěček
MPMarkéta Pišlová
Markéta Pišlová
JBJosef Beranek
Josef Beranek
ADAleksandra Dumicic
Aleksandra Dumicic
Background/Objectives: Omeprazole undergoes degradation in acidic conditions, which makes it unstable in low pHs found in the gastric environment. The vast majority of already marketed omeprazole formulations use enteric polymer coatings to protect the drug from exposure to acidic pH in the stomach, allowing for drug release in the small intestine where the pH is higher. This study aimed to explore the technical aspects of using stomach acid neutralizers as an alternative to polymeric coatings for omeprazole. Methods: After evaluating various neutralizers, magnesium oxide and sodium bicarbonate were chosen to be incorporated into capsules containing omeprazole, which then underwent in vitro dissolution testing to assess their ability to maintain optimal pH levels and ensure appropriate dissolution kinetics. Hygroscopicity and chemical stability of the selected formulation were tested to prove pharmaceutical quality of the product. An in vivo pharmacokinetic study was conducted to demonstrate the efficacy of the omeprazole–sodium bicarbonate formulation in providing faster absorption in humans. Results: Sodium bicarbonate was selected as the most suitable antacid for ensuring omeprazole stabilization. Its quantity was optimized to effectively neutralize stomach acid, facilitating the rapid release and absorption of omeprazole. In vitro studies demonstrated the ability of the formulation to neutralize gastric acid within five minutes. In vivo studies indicated that maximum concentrations of omeprazole were achieved within half an hour. The product met the requirements of pharmaceutical quality. Conclusions: An easily manufacturable, fast-absorbing oral formulation was developed as an alternative to enteric-coated omeprazole.

24 February 2023 in IUCrJ
Verified
Journal Article
Open access
PDF file
JJJan Jirát
Jan Jirát
JRJan Rohlicek
Jan Rohlicek
JKJakub Kaminsky
Jakub Kaminsky
TJTomáš Jirkal
Tomáš Jirkal
LRLuděk Ridvan
Luděk Ridvan
MSMiroslav Soos
Miroslav Soos
The transformation processes of non-solvated ibrutinib into a series of halogenated benzene solvates are explored in detail here. The transformation was studied in real time by X-ray powder diffraction in a glass capillary. Crystal structures of chlorobenzene, bromobenzene and iodobenzene solvates are isostructural, whereas the structure of fluorobenzene solvate is different. Four different mechanisms for transformation were discovered despite the similarity in the chemical nature of the solvents and crystal structures of the solvates formed. These mechanisms include direct transformations and transformations with either a crystalline or an amorphous intermediate phase. The binding preference of each solvate in the crystal structure of the solvates was examined in competitive slurry experiments and further confirmed by interaction strength calculations. Overall, the presented system and online X-ray powder diffraction measurement provide unique insights into the formation of solvates.