Multicompartment Self-assemblies of Triblock Copolymer for Drug Delivery

Novel multicompartment self-assemblies of triblock copolymer polystyrene–polyisoprene–poly(2-vinylpyridine) (PS-PI-P2VP) for drug delivery are demonstrated. The triblock copolymer assemblies in dilute solutions in a common solvent (tetrahydrofuran) undergo transformations from core-shell-corona micelles to multicompartment micelles by adding P2VP-selective solvent (water). The effects of water content and pH on the assembled structures were systematically investigated. Multicompartment micelles are also obtained by adding a surfactant, 4-biphenylcarboxylic acid, into the solution. Such multicompartment self-assemblies are used as carriers for encapsulation and release of an anticancer drug doxorubicin hydrochloride (DOX). The drug loading content and drug loading efficiency of DOX were evaluated. The DOX release experiments were performed at 37°C under pH 5.5 and pH 7.4. The DOX release rate was improved as pH decreased from pH 7.4 to 5.0, with 45.6% release of DOX in 32 h.