Complex micelles formed from two dlblock copolymers for applications in controlled drug release

Abstract

Double-responsive core-shell-corona complex micelles for applications in drug release were formed from self-assembly of two diblock copolymers PtBA-b- PNIPAM and PtBA-b-P4VP. The two diblock copolymers coaggregated into core-shell complex micelles in acidic water with the hydrophobic PtBA blocks as the common core and soluble PNIPAM/P4VP blocks as the mixed shell. Increasing temperature or pH value, the micelles converted into core-shell-corona micelles because of the collapse of PNIPAM or P4VP blocks as the inner shell and soluble P4VP or PNIPAM chains stretching outside as the outer corona. The anti-inflammation drug naproxen (NAP) was loaded as the model drug in micelles in acidic water and released because of the ionlzation of NAP in alkaline solutions. Compared with pure core-shell micelles, release of NAP from core-shell-corona complex micelles avoided the burst diffusion and the release rate Is more easily controlled by tuning the composition of the mixtures or by adjusting the pH of the medium, © 2009 Wiley Periodicals, Inc.