Cyclodextrins, amphiphillic

Lin, J. (1995), Synthese des cyclodextrins amphiphiles et etude de leur incorporation dans des phases phospholipidiques, Ph.D. dissertation, University of Paris, Paris. 

Lemos-Senna, E. (1998), Contribution a l etude pharmacotechnique et physicochimique de nanospheres de cyclodextrins amphiphiles comme transporteurs de principes actifs, Ph.D. thesis, University of Paris, Paris. 

Hashimoto, S. Thomas, J.K. Fluorescence study of pyrene and naphthalene in cyclodextrin-amphiphile complex systems. J. Am. Chem. Soc. 1985, 107 (16), 4655-4662. 

FIG. 6.1 I Amphiphilic P-cyclodextrin, amphiphilic azobenzene, and a schematic representation of the molecular arrangement of their inclusion complex in LBK films (adapted with permission from reference 51). 

Recently, we have also prepared nanosized polymersomes through self-assembly of star-shaped PEG-b-PLLA block copolymers (eight-arm PEG-b-PLLA) using a film hydration technique [233]. The polymersomes can encapsulate FITC-labeled Dex, as model of a water-soluble macromolecular (bug, into the hydrophilic interior space. The eight-arm PEG-b-PLLA polymersomes showed relatively high stability compared to that of polymersomes of linear PEG-b-PLLA copolymers with the equal volume fraction. Furthermore, we have developed a novel type of polymersome of amphiphilic polyrotaxane (PRX) composed of PLLA-b-PEG-b-PLLA triblock copolymer and a-cyclodextrin (a-CD) [234]. These polymersomes possess unique structures the surface is covered by PRX structures with multiple a-CDs threaded onto the PEG chain. Since the a-CDs are not covalently bound to the PEG chain, they can slide and rotate along the PEG chain, which forms the outer shell of the polymersomes [235,236]. Thus, the polymersomes could be a novel functional biomedical nanomaterial having a dynamic surface. 

Selective inclusion of naphthalene derivatives by monolayers of amphiphilic cyclodextrins at the air/water interface [23]. 

Figure 11. Amphiphilic cyclodextrins (Host molecules) and naphthalene derivatives (Guests).

Multihydroxyl containing monomeric or oligomeric p-cyclodextrins (PCD) such as those attained by grafting with glycidyl ethers of protected polyols (glycerol and pentitols) appeared rather promising components for their amphiphilic character, connected to the presence of an hydrophobic pocket and an external hydrophilic shell with an amplified number of hydroxyl groups. 

Part II starts with the possibilities of ACE for characterizing the relevant physicochemical properties of drugs such as lipophilicity/hydrophilicity as well as thermodynamic parameters such as enthalpy of solubilization. This part also characterizes interactions between pharmaceutical excipients such as amphiphilic substances (below CMC) and cyclodextrins, which are of interest for influencing the bioavailability of drugs from pharmaceutical formulations. The same holds for interactions of drugs with pharmaceutical vehicle systems such as micelles, microemulsions, and liposomes. 

Yabe A, Kawabata Y, Niino H, Tanaka M, Ouchi A, Takahashi H, Tamura S, Tagaki W, Nakahara H, Fukuda K. Cis-trans isomerization of azobenzenes included as guests in Langmuir-Blodgett films of amphiphilic beta-cyclodextrin. Chem Lett 1988 l-4. 

This paper is not a review covering the entire field of carbohydrate-recognition in any organized system. Many excellent papers have already been devoted to supramolecular systems such as cyclodextrins, podands, coronands or cryptants able to entrap carbohydrate molecules [1]. This article only deals with the molecular recognition of mono and oligosaccharides in organized self-assemblies of amphiphilic carbohydrates (possibly blended with other lipids) in aqueous medium i.e. in assemblies mimicking the cell membrane. 

Ferro, S., Jori, G., Sortino, S., Stancanelli, R., Nikolov, P., Tongon, G., Ricchelli, F., and Mazzaglia, A. (2009). Inclusion of 5-[4-(l-dodecanoylpyridinium)-10,15,20-triphenylpor-phine in supramolecular aggregates of cationic amphiphilic cyclodextrines Physic-chemical characterization of the complexes and strengthening of the antimicrobial photosensitizing activity. Biomacromolecules 10(9), 2592-2600. 

Cyclodextrin-substituted molecular channel approaches have now been extended to include acyl substituents through a covalent bond formation. Stearoyl and methyl cholate-substituted cyclodextrins 10 and 11, respectively, have been synthesized. It may be worthwhile commenting on the molecular design of methyl cholate-substituted a-cyclodextrin. All of the ether groupings are convergent at the inner side of the steroidal backbone of a bent structure to make the molecule amphiphilic. Once the cyclodextrin derivative is incorporated into the membrane phase, it may easily be expected that the ether parts are assembled inside the channel in the sea of hydrophobic lipid molecules and the hydrophobic steroidal skeletons cover its outside to stabilize the inner hydrophilic pore (Figure 13). 

In polar solvents amphiphilic molecules, that is molecules with a polar head and hydrophobic tail , tend to form various aggregates. The structure of micelles is usually much more complicated than that schematically shown in Figure 1.4 (see the pertaining discussion in Section 2.3). Nevertheless, in water they can include nonpolar molecules into their voids acting like surfactants applied in toiletry [15]. Similarly to cyclodextrins such as 11 [6, 16] and liquid crystals [7] discussed in Section 2.6, surfactants are examples of few supramolecular systems which have found numerous practical applications. 

Research Focus Synthesis of amphiphilic terpolymers containing ethylene oxide and (R)-3-hydroxybutyrate and hydrogels containing cyclodextrin. Originality Ongoing 3-year investigation. 

Memiolu, E., Bochot, A., Sen, M., Sharon, D., Duchene, D., Hincal, A.A. (2002). Amphiphilic p-cyclodextrins modified on the primary face synthesis, characterization and evaluation of their potential as novel excipients in the preparation of nanocapsules. Journal of Pharmaceutical Sciences, 91, 1214-1224. 

Skiba, M., Nemati, F., Puisieux, F., Duchene, D., Wouessidjewe, D. (1996). Spontaneous formation of drug-containing amphiphilic p-cyclodextrin nanocapsules. International Journal of Pharmaceutics, 145, 241-245. 

Because of their low solubilities in the aqueous phase, the hydroformylation of higher alkenes (>C2) is still a challenging problem. In addition to fluorous biphasic catalysis, possible solutions, which have been addressed, include the addition of surfactants240,241 or the use of amphiphilic ligands242-244 to enhance mutual solubility or mobility of the components across the phase boundary and thereby increase the rate of reaction. The use of polar solvents such as alcohols,245 p-cyclodextrin,246 cyclodextrin ligands,247 248 thermoregulated phase-transfer... 

J and Yabe et al. [155J have formed LB films of amphiphilic derivatives of jS-cyclodextrin and have incorporated azobenzene derivatives into them in such a way as to form a host-guest complex. Many workers have used the cis to trans change of structure referred to above and brought about by ultraviolet irradiation to change some measurable physical parameter of LB films formed from azobenzene derivatives [156-62J. 

The incorporation of such compounds into mixed Langmuir-Blodgett films built from a fatty acid (see 97) [8.92] or from an amphiphilic cyclodextrin [8.93] produces oriented arrangfements presenting marked NLO features. 

The same push-pull carotenoid can also be introduced into LB multilayers built from 1/1 mixtures with an amphiphilic cyclodextrin. The polyenic chains are again perpendicular to the substrate and some carotenoid molecules do not aggregate, but are isolated by the host substance (21). 

The reaction which is accelerated by the presence of water can be carried out in water when a 2/3-cyclodextrin-[Rh(OH)(cod)]2,943,944 [Rh(cod)Cl]2/TPPTS,945 or amphiphilic resin-supported rhodium(i) complex was used.946 It was also reported that potassium alkenyl and aryltrifluoroborates [RBF3]K undergo similar addition to enones in the presence of an Rh(i) catalyst.935,947,948 The cationic rhodium(i) complexes such as [Rh(cod)]BF4, [Rh(cod)(CH3CN)2]BF4, or its combination with a diphosphine ligand (dppp or dppb) efficiently catalyzed the reaction. The neutral complexes, generated in situ from Rh(acac)(GH2=GH2)2, or Rh(acac)(coe)2, and dppp or dppb, were also effective. The effects of catalysts, solvents, and bases,949 and the mechanism of catalytic cycle950 have been studied in detail. 

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