PLGA nanoparticle-reinforced supramolecular peptide hydrogels for local delivery of multiple drugs with enhanced synergism.

Localized drug delivery offers great therapeutic efficacy at local tissues while avoiding the systemic toxicity of drugs. Yet it demands the development of structurally-stable drug carrier systems with excellent injectability, as well as the capability to facilitate controlled release of multiple drugs. Herein, we describe the design and synthesis of a supramolecular hydrogel (Cis/Peptide@NP/Irino) for the combined delivery of cisplatin (Cis) and irinotecan (Irino). The self-assembled hydrogel consisted of an inner phase of irinotecan-loaded PLGA nanoparticles (NP/Irino) and an outer phase of cisplatin-loaded peptide nanofibers (Cis/Peptide). Through the structural reinforcement of PLGA nanoparticles, the Cis/Peptide@NP/Irino hydrogel exhibited better mechanical properties than Cis/Peptide or Peptide hydrogels. With excellent shear-thinning properties, it facilitated the development of a localized drug delivery system with an improved retention time in vivo. The hydrogel incorporated two anticancer drugs, Cis and Irino, at the Peptide and PLGA domains, respectively, and exhibited a faster release of Cis prior to the continuous release of Irino in vitro. Furthermore, the Cis/Peptide@NP/Irino formulation showed a better inhibition efficacy against the proliferation of cancerous A549 cells, with the synergism of Cis and Irino exceeding that of the simple solution mixtures, which was plausibly due to the enhanced cellular uptake of drugs through endocytosis. We believe that structurally-stable supramolecular hydrogels show great promise in the local delivery of various drug combinations for cancer therapy.