The Influence of Hydrophobic Blocks of PEO-Containing Copolymers on Glyceryl Monooleate Lyotropic Liquid Crystalline Nanoparticles for Drug Delivery.

Theodore Sentoukas,Maria Chountoulesi,Aleksandra Kordyka,Costas Demetzos,Stergios Pispas,Barbara Trzebicka,Marcin Godzierz,Tomasz Konieczny,Aleksander Forys,Barbara Mendrek

doi:10.3390/polym13162607

Abstract

The investigation of properties of amphiphilic block copolymers as stabilizers for non-lamellar lyotropic liquid crystalline nanoparticles represents a fundamental issue for the formation, stability and upgraded functionality of these nanosystems. The aim of this work is to use amphiphilic block copolymers, not studied before, as stabilizers of glyceryl monooleate 1-(cis-9-octadecenoyl)-rac-glycerol (GMO) colloidal dispersions. Nanosystems were prepared with the use of poly(ethylene oxide)-b-poly(lactic acid) (PEO-b-PLA) and poly(ethylene oxide)-b-poly(5-methyl-5-ethyloxycarbonyl-1,3-dioxan-2-one) (PEO-b-PMEC) block copolymers. Different GMO:polymer molar ratios lead to formulation of nanoparticles with different size and internal organization, depending on the type of hydrophobic block. Resveratrol was loaded into the nanosystems as a model hydrophobic drug. The physicochemical and morphological characteristics of the prepared nanosystems were investigated by dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), fast Fourier transform (FFT) analysis and X-ray diffraction (XRD). The studies allowed the description of the lyotropic liquid crystalline nanoparticles and evaluation of impact of copolymer composition on these nanosystems. The structures formed in GMO:block copolymer colloidal dispersions were compared with those discussed previously. The investigations broaden the toolbox of polymeric stabilizers for the development of this type of hybrid polymer/lipid nanostructures.

Highlights

Lipids, as a primary component of liposomal drug delivery systems, have been at the focus of scientific interest owing to their unique self-assembly features
The chemical composition of amphiphilic polymeric stabilizers poly(ethylene oxide) (PEO)-b-poly(lactic acid) (PLA) and PEO-b-PMEC affected the size, as well as the morphology of prepared nanosystems. Both block copolymers used in our study were found to provide stable glyceryl monooleate (GMO)-based colloidal dispersions, at least at the studied ratios
We assume that the present nanosystems were stable as it was in the case of previously studied GMO:PEO-b-PCL [28] and as shown for Pluronic F127 systems [27,62]

Summary

Introduction

As a primary component of liposomal drug delivery systems, have been at the focus of scientific interest owing to their unique self-assembly features. It has been proven that the copolymers play a key role on the resulting formulation and determining the mesophases of final structures, while it prevents unfavorable interactions between nanoparticles, such as aggregation [27,28] In this case, hydrophilic block should be on the outer rim in the role of a hydrophilic corona, while the hydrophobic blocks should be anchored inside the lipid bilayer, forming hydrophobic interactions with the hydrophobic lipid tails. The polymeric stabilizers can be carefully designed to provide extra properties that are extremely important due to the potential applications of lipid-based LLC for the drug delivery systems, such as stimuli-responsiveness [26,32,33]. The finding of alternative amphiphilic block copolymers has been developing very fast, but the selection process of stabilizers is difficult, since it depends on many factors such as chemical structure, molar mass and hydrophobic–hydrophilic ratio of the chosen polymers [26,33,34]

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