Formulation and Evaluation of PLGA Nanoparticulate-Based Microneedle System for Potential Treatment of Neurological Diseases

The tight structure of the blood-brain barrier severely limits the level of drug therapy for central nervous system disorders. In this study, a novel composite delivery system combining nanocarrier and microneedle technology was prepared to explore the possibility of transdermal delivery of drugs to work in the brain.Nanoparticle solutions containing paroxetine and rhodamine-B were prepared using PLGA as a carrier by the emulsification-solvent volatilization method. Then, they were mixed with hyaluronic acid and the PLGA nanoparticulate-based microneedle system (Rh-NPs-DMNs) was prepared by a multi-step decompression-free diffusion method. The particle size, zeta potential, and micromorphology of the nano solution were measured; the appearance, mechanical strength, dissolution properties, and puncture effect of the Rh-NPs-DMNs were evaluated; also, it was evaluated for in vivo live imaging properties and in vitro skin layer transport and distribution properties.The mean particle size of Rh-NPs was 96.25 ± 2.26 nm; zeta potential of 15.89 ± 1.97 mV; PDI of 0.120 ± 0.079. Rh-NPs-DMNs had a high needle content of 96.11 ± 1.27% and a tip height of 651.23 ± 1.28 μm, with excellent mechanical properties (fracture force of 299.78 ± 1.74 N). H&E skin tissue staining showed that Rh-NPs-DMNs produced micron-sized mechanical pores approximately 550 μm deep immediately after drug administration, allowing for efficient circulation of the drug; and the results of in vivo imaging showed that Rh-B NPs DMNs had a faster transport rate than Rh-B DMNs, with strong fluorescent signals in both brain (P<0.01) and hippocampus (P<0.05) 48 h after drug administration.Nanoparticles can prolong blood circulation time and intracerebral retention time and have certain brain-targeting properties due to their excellent physical properties. The use of microneedle technology combined with nanocarriers provides new ideas for delivery systems for the treatment of central neurological diseases.