Ultrasound-mediated drug release from micelles based on poly(2-oxazoline) terpolymers and triblock copolymer

Ultrasound (US)-mediated drug delivery has been widely investigated in the past decades, due to the advantages of US (mainly non-invasiveness and absence of side effects) over other energy sources1. Besides the well-known direct bioeffects of US on different tissues (bone, muscle, cartilage, etc.) and their capability to enhance transdermal drug delivery and tissue drug uptake, it has been shown that US can be used to release molecules (drugs, DNA, proteins, etc.) from different carriers, e.g., microbubbles, liposomes, and polymeric micelles2. Polymeric micelles are self-assembled structures formed by amphiphilic copolymers which are able to enclose hydrophobic drugs. They can be used in the nanomedicine field to reduce the side effects of systemic administration, especially if coupled with an external triggering mechanism. The most studied type of US-triggered micelles is the one based on Pluronics, consisting of triblock copolymers composed of poly(ethylene glycol) and poly(propylene glycol)3. In this study we propose an alternative micelle formulation based on poly(2-oxazoline) terpolymers and triblock copolymer and we demonstrate a tunable dexamethasone (Dex) release kinetics enabled by non-focused US