(583c) One-Step Fabrication of Agent-Loaded Biodegradable Microspheroids for Drug Delivery and Imaging Applications

Non-spherical particles may offer advantages over conventional spherical systems for vascular wall-targeted imaging and drug delivery applications for the treatment of several diseases. This work describes the novel fabrication of agent-loaded poly(lactic-co-glycolic acid) (PLGA) spheroid carriers via oil-in-water (O/W) and water-in-oil-in-water (W/O/W) emulsion solvent evaporation (ESE) methods, respectively. The versatility of this technique is demonstrated via the loading of a variety of therapeutics including paclitaxel, bovine serum albumin, and cadmium sulfide fluorescent nanospheres into PLGA prolate spheroids. The encapsulation efficiency for spheroids made via O/W emulsions is found to be highest at low aqueous phase surfactant concentrations and high oil phase volume fractions while encapsulation efficiency for spheroids made from W/O/W is highest at high aqueous phase surfactant concentrations and basic aqueous phase pH values. We show that rods fabricated via the W/O/W method display less polydispersity than ones via the O/W.  Overall, particle volume polydispersity in the ESE method can be minimized with high stir rate and high PLGA concentration while aspect ratio polydispersity can be minimized via use of high stir rate, as well as high aqueous phase Tris concentration and pH. The ESE technique is an attractive alternative over recently described methods for fabrication of non-spherical particles due to its simplicity in setup, high particle yield and adaptability to a variety of biodegradable polymers and therapeutics.