Electron dispersive X-ray spectroscopy and degradation properties of hyaluronic acid decorated microparticles.

• Microparticles based on PLGA/poloxamers have been decorated with hyaluronic acid with no chemical reaction. • EDS results indicate the migration of ethylene oxide segments of poloxamers towards microparticle surface. • Poloxamers only partially blend in PLGA-containing bulk of microspheres. • Microparticle degradation is strongly slowed down in the presence of poloxamers. The purpose of this study was to produce poly(DL-lactic-co-glycolic acid) (PLGA) – based microparticles (MPs), externally decorated with hyaluronic acid (HA). The MPs are intended for intravitreal injections in the treatment of posterior eye segment and have been designed to prolong the release of growth factors into the vitreous body, therefore aiming to increase the time interval between two consecutive injections. The MPs, prepared by a modified double emulsion-solvent evaporation technique and loaded with bovine serum albumins (BSA) and ciliary neurotrophic factor (CNTF), were spherical, with a diameter around 70 μm and a >90% encapsulation efficiency. Energy Dispersive Spectroscopy (EDS) outcomes indicated that HA presence in the external aqueous phase of the emulsion did affect the surface properties of MPs. Moreover, poloxamers drastically slowed down MP degradation properties which are, in turn, closely related to their ability to prolong drug release. This is promising for the envisaged application of the produced MPs. Further work will be devoted to optimizing MP formulation with respect to the envisaged intravitreal route of administration. [ABSTRACT FROM AUTHOR]