Polyethylene glycol micelles

By solubilizing very viscous aqueous solutions of polyethylene glycol in AOT/iso-octane solutions, it has been observed that the polymer leads to a decrease in the intermi-cellar interactions and enhances the stability of very large droplets with R values ranging from 55 to 150. The largest reversed micelle may contain up to 200 polymer molecules [238],... 

The solubility in polyethylene glycol 400 and in aqueous solution of other polyethylene glycols has been described.65-66 The effect of selected surfactants above and below the critical micelle concentration (CMC) on aspirin solubility67 was studied. 

In a recent study, Jin and Kaplan (2003) demonstrate the formation of silk fibroin aggregates in the presence of polyethylene glycol, and present a step by step model for fiber formation based on the principle of micelle formation, and driven by dehydration as well as flow elongation. During this process, hydrophobic chains are exposed to the solvent, but because of the molecules high free energy, water solvation is unfavorable and phase separation followed by aggregation predominates. 

AA BAA CMC CPB CTAB DM SO IPC MVPQ PAA PDADMAB PEG PIPAA SDS SMA TEMED acrylamide methylene bisacrylamide critical micelle concentration cetylpyridinium bromide cetyltrimethylammonium bromide dimethylsulfoxide interpolymer complex methylvinylpiridine units quaternized by dimethyl sulfate poly(acrylamide) poly(diallyldimethylammonium bromide) polyethylene glycol) poly(isopropylacrylamide) sodium dodecyl sulfate sodium methacrylate tetramethylethylenediamine... 

Yamamoto, Y, Y. Nagasaki, Y. Kato, Y. Sugiyama, and K. Kataoka (2001). Long-circulating polyethylene glycol)-poly(D-L-lactide) block copolymer micelles with modulated surface chacfcjdSontrolled Release, 77 27-38. 

However, Yokoyama et al. (1994) reported that a ratio between the chemically conjugated and physically entrapped ADR (i.e., DOX) was not determined, and considerable amounts of adriamycin derivatives formed and were incorporated in the micelles. Yokoyama et al. (1998) quantitatively measured the ADR incorporated in the inner core using the improved synthetic method, and analyzed the effects of the ADR contents (both by chemical conjugation and physical entrapment) on micelle stability andn vivo antitumor activity. The copolymer used by Yokoyama et al. (1998) was polyethylene glycol)-fepoly(aspartic acid) block copolymer (PB P(Asp)). The chemical conjugation and physical entrapment methods can be referred to in the earlier section of preparation of polymeric micelles. 

Forrest, M. L., C.-W. Won, A. W. Malick, and G. S. Kwon. 200l8i vitro release of the mTOR inhibitor rapamycin from polyethylene glycol)- boly(8-caprolactone) micelled. Control. Rel.110 370-377. 

Jette, K. K., D. Law, E. A. Schmitt, and G S. Kwon. 2004. Preparation and drug loading of polyethylene glycol)-block-poly(e-caprolactone) micelles through the evaporation of a cosolvent azetRtigjei. 

Kim, S. Y., I. G. Shin, Y. M. Lee, C. S. Cho, and Y. K. Sung. 1998. Methoxy polyethylene glycol) -and caprolactone amphiphilic block copolymeric micelle containing indomethacin. II. Micelle formation and drug release behaviorfe.Control. Rel.51 13-22. 

Harada, A. and Kataoka, K. (1995) Formation of polyion complex micelles in an aqueous milieu from a pair of oppositely-charged block copolymers with polyethylene glycol) segments. Macromolecules, 28, 5294-5299. 

Newkome et al. were the first to synthesise symmetrical, quater-directionaF cascade molecules with a carbon scaffold bearing 36 terminal carboxyl groups -all at an equal distance from the neopentyl core (Fig. 6.20a). The carboxyls were converted into the corresponding ammonium and tetramethylammonium car-boxylates. Synthesis of these dendritic unimolecular micelles with hydrophobic core and hydrophilic shell was accomplished up to the fourth generation by coupling of a dendritic hypercore (constructed from 4,4-bis(4 -hydroxyphenyl)-pentanol monomer) and PEG mesylate (PEG = polyethylene glycol). Dyes such... 

While it might seem reasonable to use a generic marker such as polyethylene glycol, which is completely eliminated without absorption (used to verify integrity of the epithelial barrier), it is important for the marker to have physical properties similar to the nutrient in question because of the complexity of the postprandial intestinal milieu - a thick slurry of mixed micelles, oil and water phases, and suspended particles. The marker should partition among the phases similarly to the analyte of interest and should have similar intestinal transit times. Thus, sugars must be used to trace sugars, sterols to trace sterols, etc. 

Oishi M, Hayama T, Akiyama Y, Takae S, Harada A, Yamasaki Y, Nagatsugi F, Sasaki S, Nagasaki Y, Kataoka K (2005) Supramolecular assemblies for the cytoplasmic delivery of antisense oligodeoxynucleotide polylon complex (PIC) micelles based on polyethylene glycol)-S,S-oligodeoxynucleotide conjugate. Biomacromolecules 6 2449-2454... 

Materials that are solubilized in polyethylene glycol can be solubilized in the polyoxyethylene chains on the surface of a nonionic micelle. Ismail, Gouda, and Motawi found that the micellar partition coefficients of barbiturates in polysorbates 20, 40, 60, and 80 is a function of the solute substituents and is proportional to the octanol-water partition coefficient of the barbiturate. Similarly, Ikeda, Kato, and Tukamoto showed that the solubilization of alkyl barbiturates by polyoxyethylene lauryl ether is not dependent upon the number of carbons in the substituents. Since the different polysorbates contain different aliphatic groups, the rather small dependence of solubilization upon polysorbate number (i.e., upon alkyl chain length) suggests that the barbiturates are not solubilized primarily in the hydrocarbon portion of the micelle. Gouda, Ismail, and Motawi showed that the solubilization of barbiturates in polyoxyethylene stearates is proportional to the number of polyoxyethylene units in the surfactant. 

The alkaline hydrolysis of ethyl acetate has been shown to be inhibited by polyethylene glycol and by mixed micelle... 

Lukyanov AN, Gao Z, Torchilin VP (2003) Micelles from polyethylene glycol/phosphati-dylethanolamine conjugates for tumor drug delivery. J Control Release 91 97-102... 

---