A Novel Method for Preparing Uniform-Sized PLGA Microspheres and the Application in Anti-tubercular Drug Delivery

Purpose The size was a key factor influencing the drug loading, release, and delivery efficacies of poly (lactic-co-glycolic) acid (PLGA) microspheres (MS). The purpose of the study was to explore a novel and simple method to prepare uniform-sized PLGA MS for drug delivery. Methods Different from routine homogenizer, a vortex shaker was employed for emulsification during the preparation of PLGA MS. To enhance the homogeneity of resulted PLGA MS, a glass bead was used to facilitate the emulsification. The size of PLGA MS was controlled by adjusting the working frequency and time of vortex shaker. Then, selective centrifugation was used to further enrich PLGA MS of desired size. The resulted PLGA MS were systematically evaluated in anti-tubercular drug delivery. Results Compared with the routine stirring-based method, the novel method possessed a higher efficiency of emulsification and resulted in more homogenous MS under similar conditions. The produced PLGA particles were of a narrow size distribution, which could be 1 to 5 μm by adjusting the working frequency and time of vortex shaker. The narrow size distribution made it rather easy to enrich PLGA MS of specific size through selective centrifugation. Then, to evaluate the potential of the PLGA MS for drug delivery, 2–3-μm sized PLGA MS were selected to deliver anti-tubercular drug rifampicin (RFP). In vitro experiments demonstrated that the loaded RFP could be well-controlled release and delivered into macrophages. Anti-tubercular experiments showed that the uniform-sized MS as carriers of RFP significantly enhanced the therapeutic efficacy of the drug. Conclusion Collectively, the study provided a novel and simple method for preparing uniform-sized PLGA MS, which may be of potentially wide applications.