Modulating pluronics micellar rupture with cyclodextrins and drugs: Effect of pH and temperature

Abstract

[EN]Micelles of the triblock copolymer Pluronic F127 can encapsulate drugswith various chemical structures and their architecturehasbeenstudiedbysmallangleneutron scattering(SANS). Interactionwithaderivativeofβcyclodextrin,namely,heptakis(2,6diO methyl)βcyclodextrin(DIMEB), inducesacompletebreakupof themicelles, providinga mechanism for drug release. In the presence of drugs partitioned within the micelles, competitiveinteractionsbetweenpolymer,drugandcyclodextrinleadtoamodulationof the micellarrupture,dependingonthenatureofthedrugandtheexactcompositionoftheternary system.These interactions canbe further adjustedby temperatureandpH.While themost widelyacceptedmechanismfortheinteractionbetweenPluronicsandcyclodextrinsisthrough polypseudorotaxane (PR) formation, involving the threading of βCD on the polymer backbone, timeresolvedSANSexperimentsshowthatdemicellisationtakesplaceinlessthan 100ms, thusunambiguouslyrulingoutaninclusioncomplexbetweenthecyclodextrinandthe polymerchains.