Modulating protein release profiles by incorporating hyaluronic acid into PLGA microparticles Via a spray dryer equipped with a 3-fluid nozzle.

PURPOSE: The purpose of this study was to modulate the release profiles of the model protein drug from spray dried poly(DL-lactic-co-glycolic acid) (PLGA) microparticles by incorporating hyaluronic acid (HA) in the formulation. METHODS: Bovine serum albumin (BSA)-loaded PLGA microparticles with or without HA were prepared using a spray dryer equipped with a 3-fluid nozzle. The effects of HA on the surface tension and the rheological behavior of the inner feed solution were investigated. The physicochemical properties of the resulting microparticles were characterized using scanning electron microscopy (SEM), laser diffraction (LD), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). Circular dischoism (CD) was used to characterize conformational integrity of BSA released from the microparticles. RESULTS: Spherical microparticles with D50 of 5-10 µm were obtained. Addition of HA in inner feed solutions increased the feed viscosity, but with no influence on the surface tension. All inner feed solutions showed non-Newtonian shear thinning behavior and the rheological properties were not time dependent. The CLSM and XPS analyses suggested a core-shell like structure of the microparticles when HA was incorporated. The release profiles of BSA were extended and the initial burst releases were suppressed with an increase in HA in the microparticle formulations. In addition, HA seemed to protect BSA from degradation upon the spray-drying process. CONCLUSIONS: The present work demonstrates the potential of HA to modulate protein release profile from PLGA microparticle formulations produced via spray drying using 3-fluid nozzle.