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Study of release kinetics of hydrophobic drug paclitaxel into hydrogels.
Batěk, Jan ; Bosáková, Zuzana (advisor) ; Jelínek, Ivan (referee)
In this diploma thesis, hydrogels based on 2-hydroxymethacrylate (HEMA) were studied. Their possible use to study the release kinetics of the hydrophobic anticancer drug paclitaxel (PTX) was investigated in order to approach the conditions simulating in vivo environments. Paclitaxel is a drug with strong side effects, which can be partially prevented by appropriate local application. In this work, polylatide (PLA) nanofibers with incorporated drug was studied. Furthermore, the effect of the addition of polyethylene glycol (PEG) with a molecular weight of 20 kDa and CD to the structure of PLA nanofibers on the profiles of PTX release into various environments simulating in vivo environments was studied. An analytical HPLC method with UV detection was used to monitor the release kinetics of PTX. The addition of PEG to PLA nanofibers resulted in a significantly higher amount of hydrophobic drug released, which was also released over a longer period of time, compared to fibers containing only PTX. This trend was evident in both experiments monitoring the release of PTX into PBS and into hydrogel matrices. The effect of CD addition on PTX release was evident only in monitoring the kinetics of PTX release into hydrogel matrices, where there was a greater release of PTX from these fibers. An increase in...
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New Methods of Oxygen Removal from Analyzed Solutions in Voltammetric Determination of Organic Compounds
Batěk, Jan ; Vyskočil, Vlastimil (advisor) ; Schwarzová, Karolina (referee)
The aim of this Bachelor Thesis was to verify new methods of oxygen removal from analyzed solutions in voltammetric determination of organic compounds. A method of chemical reduction was chosen to remove dissolved oxygen. Carbohydrazide, N,N-diethylhydroxylamine and 2-butanone oxime were used for removal of dissolved oxygen. These substances are used to remove oxygen from boiler systems. The last agent used to remove oxygen was sodium sulfite. Differential pulse voltammetry (DPV) was used to monitored the ability of oxygen scavengers. The effect of pH of the solution (Britton-Robinson buffer) on oxygen removal was also investigated. A solution of 4-nitrophenol at a concentration of 1∙10−4 mol∙l−1 was used as a model substance in these assays. We have found that carbohydrazide had no effect to remove oxygen in the whole pH range. Using sodium sulphite, oxygen was removed from the analyzed solution at pH 8, 10 and 12. Determination of 4-nitrophenol was thus possible. Using N,N-diethylhydroxylamine at pH 10 and 12 and 2-butanone oxime at pH 8, 10 and 12, oxygen was removed from the analyzed solutions. However, these substances are unsuitable for the determination of 4-nitrophenol.
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