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tom Vol. 81, nr 12
2157-2169
EN
The surface properties of sodium dodecyl sulfonate (SDSn), dodecyl-b-D-glucoside (DG), dodecyltrihydroxyethylammonium bro mide (DTEAB) and sodium dodecyl sul fate (SDS) and their mixtures: SDSn/SDS, SDSn/DG and SDSn/DTEAB were studied. The miscibility and the composition of the mixed monolayers and micelles as well as the interactions between their components were analyzed with the Motomura theory. It was found that among the investigated mixed systems the best surface properties reveal the anionic-cationic mixtures. Moreover, the investigated systems mix nonideally both in the monolayers and micelles. The magnitude of the deviations from ideal behaviour increases in the order: an ionic/an ionic < an ionic/nonionic << an ionic/cationic. Both the mixed monolayers and mi celles formed from SDSn/SDS and SDSn/DG mix tures are richer, as compared to the mixed solutions, in the more surface-active component, while the mixed monolayers and micelles formed from cationic/anionic mixtures (SDSn/DTEAB) possess more symmetrical composition than the mixed solution. As it was found the interactions between molecules both in the mixed monolayers and micelles are more attractive or less repulsive as compared to those in respective one-component monolayers and micelles and the strength of these interactions increases in the order: SDSn/SDS < SDSn/DG < SDSn/DTEAB.
2
Content available CHEMICAL MODIFICATION OF CHITOSAN WITH FATTY ACIDS
100%
EN
This paper presents the results of chitosan modification with fatty acids, namely linoleic and oleic acid. We used carbodiimide as the initiator for the reaction of carboxyl and aminoglycoside functional groups. The analysis of infrared spectra confirmed the formation of chitosan derivatives. Their hydrophilic-hydrophobic properties were determined by O/W emulsification and micelles formation in aqueous systems.
EN
A series of N,O-acylated chitosan derivatives were emulsified with different fatty acids. Hydrophobically modified chitosan derivatives were expected to exhibit self-assembly behaviour resulting in micelle formation. Several parameters of the oil-in-water emulsification process were investigated: mixing method, speed and duration, volume oil phase and addition of modifiers. Their influence on micellar Z-average diameter, size distribution and Zeta potential was analysed based on dynamic light scattering measurements. There were various relations between the hydrodynamic behaviour of chitosan derivatives, their chemical structure and the process parameters. Additionally, the obtained micelles could serve as active compound carriers because they encapsulated two model substances, namely ibuprofen and α-tocopherol.
4
63%
EN
Surfactants are substances, which have surface activity in aqueous solutions [1–3]. By adsorbing on the surface (boundary of phase separation) of the system, they change the surfactant properties of the liquid. Surfactants consist of a hydrophobic part (non-polar, called “tail”) and a hydrophilic part (polar, called “head”) [1–3]. The overall structure of the surfactant molecule is shown in Figure 1. In aqueous solution after exceeding one critical micellar concentration of the CMC surfatant (Critical Micelle Concentration), the surfactant molecules aggregate to form micelles [1–5]. Knowledge of CMC values and the micelle formation in solution, it determines the properties of surfactants and their subsequent use in the chemical industry. Surfactants are used in the chemical industry, inter alia, for the production of many detergents, cosmetics, paints, dyes, agrochemicals, pharmaceuticals, food or oil [2, 3].
PL
Artykuł stanowi przegląd literaturowy dotyczący polimerów wykazujących samoorganizację makrocząsteczek — interesującej grupy materiałów o różnorodnych właściwościach i zastosowaniach, zwłaszcza medycznych — wykorzystywanych jako systemy kontrolowanego uwalniania leków. Spontaniczne grupowanie się makrocząsteczek w roztworach prowadzi do tworzenia się różnych struktur, takich jak: micele, mikro/nanosfery lub polimerosomy, w efekcie występowania pomiędzy określonymi fragmentami makrocząsteczek słabych wiązań i oddziaływań, tj. wiązań wodorowych oraz oddziaływań van der Waalsa, elektrostatycznych lub hydrofobowych. Przedstawiono wybrane formy strukturalne powstające w wyniku samoorganizacji makrocząsteczek w roztworach (wodnych i organicznych). Scharakteryzowano polimery zdolne do tworzenia takich struktur, metody ich otrzymywania oraz przykłady zastosowań w medycynie w charakterze systemów kontrolowanego uwalniania leków.
EN
The paper is a literature review concerning the polymers capable of macromolecular self-assembly — an interesting group of materials possessing diverse properties, which found various, especially medical applications, as controlled release drug delivery systems. Spontaneous assembly of macromolecules in solutions leads to the formation of various structural forms such as micelles, micro/nanospheres or polymersomes, as a result of the presence of weak bonds and interactions, i.e. hydrogen bonds as well as van der Waals, electrostatic or hydrophobic interactions, between specific parts of macromolecules. Selected structural patterns formed by self-assembly of macromolecules in organic and aqueous solutions were presented. The polymers capable of forming self-assembled structures, methods of their synthesis as well as the examples of medical applications as drug delivery systems have been described.
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