<p>Da bi se dobio sistem surfaktanata željenih osobina moguće je hemijski modifikovati već postojeće molekule površinski aktivnih supstanci, a druga mogućnost je konstrukcija binarnih smeša surfaktanata. U farmaceutskoj i prehrambenoj industriji uveliko se primenjuju binarne smeše površinski aktivnih molekula. Ukoliko je binarna mešovita micela termodinamički stabilnija od hipotetičke idealne binarne mešovite micele, onda je kritična micelarna koncentracija binarne smeše surfaktanata niža čak i od hidrofobnije gradivne jedinice mešovite micele, što znači da je za isti efekat površinske aktivnosti potrebna manja količina binarne smeše nego čistog surfaktanta. Različite gradivne jedinice binarne micele u micelarnoj pseudofazi mogu formirati specifične regije koje mogu vezivati lekove određenih strukturnih karakteristika. Pogodno je da jedna gradivna jedinica bude krute konformacije, npr. soli žučnih kiselina, dok je druga gradivna jedinica konformaciono pokretljiva (ugljovodonični nizovi iznad C10). Na taj način se povećava zapremina hidrofobne micelarne faze u odnosu na zapreminu hidrofobne micelarne faze monokomponentne micelle konformaciono krutog surfaktanta, što povećava solubilizacioni kapacitet mešovite micele u odnosu na monokomponentnu micelu krutog surfaktanta. Povećanjem dužine ugljovodoničnog niza konformaciono pokretnog surfaktanta povećava se stepen unutrašnje pokretljivosti u hidrofobnom domenu mešovite micele, što takođe povećava verovatnoću prihvatanja molekula gosta. Micelarni sistemi, kako monokomponentnih micela tako i binarnih mešovitih micela dodatno se mogu termodinamički stabilizovati povećanjem jonske jačine rastvora. Za hidrataciju katjona troše se molekuli vode iz sistema, što povećava efekat desolvatizacije hidrofobne površine surfaktanata, pa se zbog toga pospešuje samoasocijacija.</p> / <p>To obtain the surfactant system with the desired properties it is possible to chemically modify existing molecules of surface active agents. The other possibility is the construction of binary mixtures of surfactants. Binary mixtures of surface active molecules are widely used In the pharmaceutical and food industry. If the binary mixture micelle is more thermodynamically stable than the hypothetical ideal binary mixed micelle, then the critical micellar concentration (CMC) of the binary mixture of surfactants is even lower than the CMC of the more hydrophobic building block of the binary mixture. That means that for the same effect of surface activity less the amount of the binary mixture than the pure surfactants is required. The different building blocks of binary micelles in micelar pseudophase can form specific regions that can bind drugs of certain structural characteristics. It is suitable that one building block is of a rigid conformation, i.e. bile acid salts, while the second building block is of a flexible conformation (above C10 hydrocarbon arrays). In this way the volume of the hydrophobic micellar phase is increased in relation to the volume of the hydrophobic micellar phase of the monocomponent micelles of conformationally rigid surfactant, which increases the capacity of solubilisation of the mixed micelles, compared to the mono-component surfactant micelle of the rigid conformation. By increasing the length of the hydrocarbon array of the the conformational flexible surfactant, the degree of internal mobility in the hydrophobic domain of mixed micelles is also increased, which also increases the likelihood of acceptance of guest molecules. Micellar systems, of both monocomponent micelles and mixed micelles can be additionally thermodynamically stabilized by increasing the ionic strength of the solution. The hydration of cations uses the molecules of water from the system, which increases the effect of desolvatisation of the hydrophobic surface of the surfactants, and therefore promotes self-association.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)104270 |
| Date | 27 April 2017 |
| Creators | Popović Kosta |
| Contributors | Poša Mihalj, Pilipović Ana, Sakač Marija, Nikolić Božana, Tepavčević Vesna, Atanacković Krstonošić Milica, Krstonošić Veljko |
| Publisher | Univerzitet u Novom Sadu, Medicinski fakultet u Novom Sadu, University of Novi Sad, Faculty of Medicine at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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