Micelles of Amphiphilic Diblock and Triblock Copolymers Based on Poly(ethylene oxide) and Poly(e-caprolactone) and Their Potential as Nanocontainers for Drugs

The development and usage of nanoscaled carriers for effective delivery of toxic and insoluble drugs is of particular interest in recent years. One of the most convenient ways to create such therapeutic systems is self-assembling of amphiphilic block copolymers with immiscible biocompatible and biodegradable components, for example polyethers and polyesters. Two series of MOPEO-b-PCL diblock copolymers (DBCs) contained methoxypoly(ethylene oxide) (Mn = 2.5 and 4.54 kDa) and poly(ε-caprolactone) of a variable Mn and also the triblock copolymer (TBC) PCL-b-PEO-b-PCL based on poly(ethylene oxide) (Mv = 6 kDa) were synthesized and characterized by NMR spectroscopy. Their micellization in water/dioxane solutions was studied using static and dynamic light scattering, UV-Vis spectroscopy and TEM. The micelles of spherical and ellipsoidal morphology, which size and stability in a solution (estimated by CMC and - G values) grew with increase in the length of both the “core”-forming (PCL) and “corona”-forming (PEO) blocks, were found in the dilute DBC solutions. Unlike this, the “flower-like” micelles of a smallest size (66 nm) and stability formed in TBC solutions. The prospects for application of DBC and TBC micelles as biocompatible and biodegradable carriers for poorly soluble and anticancer drugs (prednisolon, doxorubicin etc.) were considered.