A series of codendrimers from polyamidoamine (PAMAM) and oligoethylene glycols (OEG) dendrons as drug carriers: the effect of OEG dendron decoration degree

Abstract

A series of codendrimers (co-D₆₄, co-D₄₈, co-D₃₂, and co-D₁₆) from polyamidoamine (PAMAM) decorated by oligoethylene glycol (OEG) dendrons with similar structures but different decoration degrees (DDs) were prepared, and their properties in aqueous solution, including particle size and morphology, were investigated. To explore the interactions between the codenderimers and drug, then find the effects of OEG dendron decoration degree, these codendrimers were utilized as drug carriers to load methotrexate (MTX). Although these drug-loaded nanoparticles presented similar particle size, morphology, thermal transition, and physical state, it was proved that codendrimers with lower DDs (co-D₃₂, 50%; co-D₁₆, 25%) were the most suitable carriers to load MTX from the drug-loading content (DLC), entrapment efficiency (EE), and cytotoxicity results. This was due to the stronger hydrophobic and electrostatic interactions between the free amine groups of the codendrimers and MTX. The results from the drug release profiles indicated that the release kinetics were not controlled only by these interactions, but that the steric hindrance of the OEG dendrons should be considered. Overall, co-D₃₂ with a moderate decoration degree could be a promising drug delivery system.