Journal
INTERNATIONAL JOURNAL OF PHARMACEUTICS
Volume 345, Issue 1-2, Pages 35-41Publisher
ELSEVIER
DOI: 10.1016/j.ijpharm.2007.07.039
Keywords
solubilisation; block copolymers; critical micelle concentrations; micelles
Categories
Ask authors/readers for more resources
Published values of the critical micelle concentration are tabulated for diblock copolymers EmPn, EmBn, EmSn, EmLn, EmVLn, and EmCLn, where E denotes a chain unit derived from ethylene oxide, P from propylene oxide, B from 1,2-butylene oxide, S from styrene oxide, L from DL-lactide, VL from gamma-valerolactone and CL from e-caprolactone, and the subscripts denote average chain lengths. Noting that log(cmc/mol dm(-3) is proportional to the standard Gibbs energy of micellisation, the dependence of this quantity on hydrophobic block length (n) is explored for a given E-block length. Superposition of data allows ranking of the hydrophobicities of the chain units. The ratios relative to the least hydrophobic unit are: P : L : B : VL : S : CL = 1 : 4 : 6 : 10 : 12 : 12 Transitions in the slope of log(cmc) versus n are assigned to changes in the unimer-micelle equilibrium and related to the formation of unimolecular micelles and, at high values of n, to the completion of that process. The formation transition is seen in the plots for all the copolymers except the least hydrophobic, EmPn. The completion transition is seen in the plots for EmCLn and EmLn copolymers, as these alone include results for copolymers with very lengthy hydrophobic blocks. (c) 2007 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available