20.500.12556/DKUM-54016 Polisaharidni aerogeli za izboljšanje biodostopnosti v vodi slabo topnih substanc Polysaccharide aerogels for improving the bioavailability of water low-soluble drugs Namen diplomskega dela je bil sintetizirati štiri različne aerogele iz guarja, ksantana, alginata in nizkometiliranega pektina. Da smo dobili gel, smo uporabili direktno metodo geliranja v etanolu, v katerem smo raztopili tudi aktivno substanco nifedipin, ki se je tako vezala na pripravljene gele. Gele smo nato superkritično sušili s CO2. Ker v superkritičnem območju obstaja le ena faza in zaradi tega ni površinskih napetosti, ki bi povzročile krčenje por v gelu, se struktura gela ne poruši. Po tem, ko so spet doseženi normalni pogoji, pa je CO2 ponovno v plinastem stanju. Dobljeni aerogeli so zaradi visoke poroznosti in velike specifične površine primerni za nosilce aktivnih substanc in nadaljnje kontrolirano sproščanje. So tudi netoksični, biokompatibilni in biorazgradljivi, zaradi česar so prijazni tako človeku kot tudi okolju. Po superkritičnem sušenju smo z in vitro testi sproščanja preverjali, kako se iz nosilcev sprošča aktivna substanca v različnih simuliranih prebavnih tekočinah. Ugotovili smo, da se je aktivna substanca iz alginatnega in pektinskega aerogela sprostila že po petih urah, med tem ko se je iz guarjevega in ksantanskega aerogela tudi po 24 h sprostila minimalna količina aktivne substance. Po končanem eksperimentalnem delu smo določili še kinetični model sproščanja. The objective of this diploma thesis was to synthesize four different aerogels from guar, xanthan, alginate and low-methoxy pectin. To achieve a gel formation a direct gelling method in ethanol was used, which was saturated with the active substance nifedipine in order to bind to the gels. The gels were then supercritical dried using CO2. This method was used due to only one existing phase in the supercritical area. It resolves in no surface tension, which could cause pore contraction and gel structure damage. After reestablishment of room conditions, CO2 returns to gaseous state. The resulting aerogels show high porosity and high specific surface area. Therefore, they could be considered as potential candidates to be used as carriers for active substances and controlled drug release. They are also nontoxic, biocompatible and biodegradable, which makes them environmentally and human-friendly. After the supercritical drying process, the release of the active substance in different simulated bodily fluids was observed with in vitro tests. We discovered that the drug was fully released from alginate and pectin aerogels after five hours while with guar and xanthan aerogels, minimal quantities were still being released after twenty-four hours. After the experimental procedure, the kinetic models of the drug release were also determined. aerogel ksantan guar pektin alginat nifedipin aerogel xanthan guar pectin alginate nifedipine true true false [M. Gračnar] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2015-08-18 10:04:46 2015-10-30 10:39:01 2022-06-04 03:10:10 2023-12-31 03:28:50 2015 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 604.2:547.458(043.2) 19422742 URN:SI:UM:DK:AEPH0GHV UN_Gracnar_Maja_2015.pdf UN_Gracnar_Maja_2015.pdf 1 DB5F85DB00861A3D919470DF2B4B25A5 d3de39b58ba1c92d1aa00edb93285ae9a9535d22b1591ba41d920ab5ba700f84 bc88141a-7c0b-11eb-bb7a-00155d0001ca https://dk.um.si/Dokument.php?lang=slv&id=80626 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0