Biodegradable Long-Circulating Polymeric Nanospheres

TLDR

Injectable nanoparticulate carriers promise site‑specific drug delivery and imaging, yet conventional ones are rapidly cleared by the reticulo‑endothelial system. The study aimed to develop monodisperse biodegradable nanospheres from amphiphilic copolymers to overcome this rapid clearance. These nanospheres were fabricated from amphiphilic copolymers, encapsulating up to 45 % drug by weight in a one‑step process, and can be freeze‑dried and redispersed without additives. In mice, the nanospheres exhibited markedly prolonged circulation, reduced liver accumulation, and retained high drug loading after freeze‑drying and re‑dispersion.

Abstract

Injectable nanoparticulate carriers have important potential applications such as site-specific drug delivery or medical imaging. Conventional carriers, however, cannot generally be used because they are eliminated by the reticulo-endothelial system within seconds or minutes after intravenous injection. To address these limitations, monodisperse biodegradable nanospheres were developed from amphiphilic copolymers composed of two biocompatible blocks. The nanospheres exhibited dramatically increased blood circulation times and reduced liver accumulation in mice. Furthermore, they entrapped up to 45 percent by weight of the drug in the dense core in a one-step procedure and could be freeze-dried and easily redispersed without additives in aqueous solutions.