|
|
Modification of hyaluronan by cholic acid and the using of these derivatives for carrier applications
Kvaková, Klaudia ; Márová, Ivana (referee) ; Velebný, Vladimír (advisor)
Amphiphilic biopolymers were synthesised using esterification of hyaluronic acid (HA) and cholic acid as hydrophobic segment. First, step of synthesis involves the activation of cholic acid carboxylic moiety by reaction with benzoylchloride and triethylamine (TEA) using as solvent tetrahydrofuran (THF). The formed mixed aliphatic/aromatic anhydride (intermediate) reacted at room temperature with hyaluronic acid catalysed by 4-(dimethylamino)pyridine (DMAP) and triethylamine and using as solvent water/THF. Hydrophobized product was identified as sodium cholyl hyaluronate (HA-CA) was obtained as product of the reaction. Structure of derivative was characterised by Nuclear magnetic resonance (NMR) and Fourier Transform - Infrared Spectroscopy (FT-IR). Size exclusion chromatography (SEC-MALLS) was used to determine molecular weight of derivative to evaluate any possible degradation of hyaluronan during modification. Rheological properties of these substances were also examined and confirmed non-degradation. The hydrophobized hyaluronic acid properties were evaluated for application as drug delivery system. Therefore, two non-polar compounds were encapsulated (coenzyme Q10 and curcumin). The size of formed polymeric micelles was characterised by dynamic light scattering (DLS).
|
|
|
Electrochemical oxidation of selected bile acids in acetonitrile
Habániková, Shannelle Diana ; Schwarzová, Karolina (advisor) ; Fischer, Jan (referee)
The concentration of bile acids is an important parameter in hepatobiliary tract diseases. This work deals with the electrochemical oxidation of the chenodeoxycholic (CDCA) and cholic acid (CA) at boron dopped diamond (BDD) electrode in comparison with the oxidation at glassy carbon (GCE) and platinum electrode (PtE), in a mixed environment of acetonitrile and water (0.26 % from 0.1 mol·l-1 HClO4, supporting electrolyte). The measurement was carried out in an electrochemical cell with salt bridge containing 0.5 mol·l-1 NaClO4 separating the working and the Pleskov's reference electrode (0.01 mol·l-1 AgNO3 and 1 mol·l-1 NaClO4 in acetonitrile). Cyclic voltammetry (CV) characterization of BDD electrode by a redox pair [Fe(CN)6]4-/3- (c = 0.1 mmol·l-1) in 1 mol·l-1 KCl was performed. Quasi-reversible behaviour was observed and the difference of the anodic and the cathodic peak potential ranged from 80 to 200 mV, depending on the scan rate. Alumina polishing (4 min) of the BDD electrode was identified as the most appropriate method of activating the surface and it was applied between consecutive voltammetric scans in the presence of CA and CDCA. Irreversible anodic peaks of CDCA and CA in acetonitrile-water (0.26 %) were observed at the relatively high potentials of about +1100 ± 100 mV, depending on...
|
|
|
Modification of hyaluronan by cholic acid and the using of these derivatives for carrier applications
Kvaková, Klaudia ; Márová, Ivana (referee) ; Velebný, Vladimír (advisor)
Amphiphilic biopolymers were synthesised using esterification of hyaluronic acid (HA) and cholic acid as hydrophobic segment. First, step of synthesis involves the activation of cholic acid carboxylic moiety by reaction with benzoylchloride and triethylamine (TEA) using as solvent tetrahydrofuran (THF). The formed mixed aliphatic/aromatic anhydride (intermediate) reacted at room temperature with hyaluronic acid catalysed by 4-(dimethylamino)pyridine (DMAP) and triethylamine and using as solvent water/THF. Hydrophobized product was identified as sodium cholyl hyaluronate (HA-CA) was obtained as product of the reaction. Structure of derivative was characterised by Nuclear magnetic resonance (NMR) and Fourier Transform - Infrared Spectroscopy (FT-IR). Size exclusion chromatography (SEC-MALLS) was used to determine molecular weight of derivative to evaluate any possible degradation of hyaluronan during modification. Rheological properties of these substances were also examined and confirmed non-degradation. The hydrophobized hyaluronic acid properties were evaluated for application as drug delivery system. Therefore, two non-polar compounds were encapsulated (coenzyme Q10 and curcumin). The size of formed polymeric micelles was characterised by dynamic light scattering (DLS).
|
guest ::
