Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

Angeliki Chroni; Thomas Mavromoustakos; Stergios Pispas

doi:10.3390/polym13071164

Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

Polymers (Basel). 2021 Apr 5;13(7):1164. doi: 10.3390/polym13071164.

Authors

Angeliki Chroni¹, Thomas Mavromoustakos², Stergios Pispas¹

Affiliations

¹ Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece.
² Department of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis, 15771 Zografou, Greece.

Abstract

The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (M_w) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA₃₀-b-POEGA₇₀ and PnBA₂₇-b-POEGA₇₃ (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA₂₇-b-POEGA₇₃ micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA₃₀-b-POEGA₇₀ + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA₃₀-b-POEGA₇₀ and PnBA₂₇-b-POEGA₇₃ micelles.

Keywords: amphiphilic block copolymers; drug delivery systems; drug encapsulation; drug release profile; drug–polymer intermolecular interactions; polymeric nanocarriers; thin film hydration method.