Colloidal stability of Pluronic F68-coated PLGA nanoparticles: A variety of stabilisation mechanisms

Poloxamers are a family of polypropylene oxide (PPO) and polyethylene oxide (PEO) tri-block copolymers that are usually employed in the micro- and nanoparticulate engineering for drug delivery systems. The aim of this work is to study the electrophoretic mobility (μeμe) and colloidal stability of complexes formed by adsorbing a poloxamer (Pluronic F68) onto poly(d,l-lactic-co  -glycolic acid) (PLGA) nanoparticles. A variety of stabilisation mechanisms have been observed for the Pluronic-coated PLGA nanoparticles, where DLVO interactions, solvent–polymer segment interactions and hydration forces play different roles as a function of the adsorbed amount of Pluronic. In addition, the μeμe and stability data of these complexes have been compared to those obtained previously using a PLGA–Pluronic F68 blend formulation. As both the μeμe and the stability data are identical between the two systems, a phase separation of both components in the PLGA–Pluronic blend formulation is suggested, being the PLGA located in the core of the particles and the Pluronic in an adsorbed shell.

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