Please use this identifier to cite or link to this item:
https://open.uns.ac.rs/handle/123456789/30436
DC Field | Value | Language |
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dc.contributor.advisor | Krstonošić Veljko | - |
dc.contributor.advisor | Poša Mihalj | - |
dc.contributor.author | Ćirin Dejan | - |
dc.contributor.other | Sakač Marija | - |
dc.contributor.other | Sebenji Ana | - |
dc.contributor.other | Čanadi Janoš | - |
dc.contributor.other | Milić Nataša | - |
dc.contributor.other | Popović Jovan | - |
dc.date.accessioned | 2020-12-14T18:23:06Z | - |
dc.date.available | 2020-12-14T18:23:06Z | - |
dc.date.issued | 2015-05-14 | - |
dc.identifier.uri | https://open.uns.ac.rs/handle/123456789/30436 | - |
dc.description.abstract | <p>Surfaktanti imaju značajnu primenu u farmaciji i medicini. Ove supstance se primenjuju u farmakoterapiji, koriste se za solubilizaciju hidrofobnih lekova, a pojedina ispitivanja pokazuju da mogu unaprediti bioraspoloživost određenih aktivnih supstanci. U poslednje vreme se sve više pažnje posvećuje ispitivanju smeša surfaktanata, pošto je utvrđeno da sistemi dva ili više surfaktanta često pokazuju poželjnija svojstva od pojedinačnih surfaktanata za aplikaciju u farmaciji i medicini. U ovoj disertaciji su ispitivani binarni sistemi osam anjona žučnih kiselina i dva nejonska surfaktanta (polisorbat 40 i polisorbat 80). Ciljevi su određivanje vrednosti kritičnih micelarnih koncentracija ispitivanih smeša surfaktanta, utvrđivanje međudejstva između različitih surfaktanta u njihovim mešovitim micelama, kao i ispitivanje uticaja stukture ispitivanih surfaktanata na fizičko-hemijske karakteristike mešovitih micela. Rezultati pokazuju da ispitivane smeše imaju znatno niže vrednosti kritičnih micelarnih koncentracija od anjona žučnih kiselina. Smeše anjona žučnih kiselina i polisorbata 40 imaju manje vrednosti eksperimentalnih kritičnih micelarnih koncentracija, od izračunatih, idealnih, vrednosti, što ukazuje na postojanje sinergističkih interakcija u mešovitim micelama. Smeše anjona žučnih kiselina i polisorbata 80 imaju uglavnom veće vrednosti kritičnih micelarnih koncentracija od idealnih vrednosti, što može biti posledica postojanja antagonističkih interakcija između gradivnih jedinica mešovitih micela. Vrednosti interakcija, koje dovode do neidealnog ponašanja sistema surfaktanata, su određene računanjem vrednosti interakcionog parametra, β<sub>1,2</sub>, prema regular solution theory. Sistemi anjona žučnih kiselina i polisorbata 40 imaju negativne vrednosti interakcionog parametra, dok sistemi anjona žučnih kiselina i polisorbata 80 imaju uglavnom pozitivne vrednosti interakcionog parametra. Poređenjem fizičko-hemijskih parametara mešovitih micela je utvrđeno da postojanje privlačnih međudejstava između hidrofilnih delova različitih surfaktanata najverovatnije potiče od vodoničnih veza koje se formiraju između hidrofilnih grupa anjona žučnih kiselina i polioksietilenskih delova. Pozitivne vrednosti β<sub>1,2</sub> parametra su najverovatnije posledica sterno krute cis dvostruke veze oleinske kiseline u molekulu polisorbata 80, usled čega se lipofilni deo ovog nejonskog surfaktanta teže pakuje u jezgru mešovitih micela. Pretpostavlja se da zbog toga dolazi do formiranja dimera anjona žučnih kiselina u mešovitim micelama u kojima se javljaju odbojne interakcije između negativno naelektrisanih karboksilatnih grupa.</p> | sr |
dc.description.abstract | <p>Surfactants have important application in pharmacy and medicine. These substances are applied in pharmacotherapy, they are used for hydrophobic drug solubilisation, and certain investigations indicate they can improve bioavailability of certain active substances. Lately, investigations of surfactant mixtures have gained a lot of attention, since it was found that systems of two or more surfactants often show more desirable properties than the individual surfactants, for application in pharmacy and medicine. In this dissertation, binary systems of eight bile acid anions and two nonionic surfactants (polysorbate 40 and polysorbate 80) were investigated. The aims were to determine values of critical micelle concentrations of investigated surfactant mixtures, interactions between different surfactants in their mixed micelles, and to investigate the influence of the structure of investigated surfactants on physico-chemical characteristics of mixed micelles. The results indicate that investigated mixtures have significantly lower values of critical micelle concentrations than bile acid anions. Mixtures of bile acid anions and polysorbate 40 have lower values of experimentally obtained critical micelle concentrations than the calculated, ideal, values, indicating the existence of synergistic interactions in mixed micelles. Mixtures of bile acid anions and polysorbate 80 have mainly higher values of critical micelle concentrations than the ideal values, what could be due to the existence of antagonistic interactions between building units of mixed micelles. The values of the interactions, attributing to the nonideal behaviour of the surfactant systems were obtained by calculating the values of the interaction parameter, β1,2 , according to the regular solution theory. Systems of bile acid anions and polysorbate 40 have negative values of the interaction parameter, while systems of bile acid anions and polysorbate 80 have mainly positive values of interaction parameter. By comparing the physico-chemical parameters of mixed micelles, it was determined that existence of attractive interactions between hydrophilic parts of different surfactants most probably originates from the hydrogen bonds, which are formed between hydrophilic groups of bile acid anions and polyoxyethylene parts. Positive values of β1,2 parameter are most probably due to sterically rigid cis double bond of oleic acid in polysorbate 80 molecule, causing the lipophilic tail of this nonionic surfactant to pack less easily in the core of mixed micelles. It is hypothesised that this influences formation of dimers of bile acid anions in mixed micelles, where repulsive interactions emerge between negatively charged carboxylate groups.</p> | en |
dc.language.iso | sr (latin script) | - |
dc.publisher | Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu | sr |
dc.publisher | University of Novi Sad, Faculty of Medicine at Novi Sad | en |
dc.source | CRIS UNS | - |
dc.source.uri | http://cris.uns.ac.rs | - |
dc.subject | Surface-Active Agents; Micelles; Bile Acids and Salts; Polysorbates | en |
dc.subject | Površinski aktivni agensi; Micele; Žučne kiseline i soli; Polisorbati | sr |
dc.title | Physico-chemical properties of mixed micelles of salts of bile acids and nonionic surfactants | en |
dc.title | Fizičko-hemijske karakteristike mešovitih micela soli žučnih kiselina i nejonskih surfaktanata | sr |
dc.type | Thesis | en |
dc.identifier.url | https://www.cris.uns.ac.rs/DownloadFileServlet/Disertacija143072864409029.pdf?controlNumber=(BISIS)92790&fileName=143072864409029.pdf&id=3642&source=BEOPEN&language=en | en |
dc.identifier.url | https://www.cris.uns.ac.rs/record.jsf?recordId=92790&source=BEOPEN&language=en | en |
dc.identifier.externalcrisreference | (BISIS)92790 | - |
dc.source.institution | Medicinski fakultet u Novom Sadu | sr |
item.fulltext | No Fulltext | - |
item.grantfulltext | none | - |
crisitem.author.dept | Medicinski fakultet, Katedra za farmaciju | - |
crisitem.author.parentorg | Medicinski fakultet | - |
Appears in Collections: | MDF Teze/Theses |
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