In vivo brain microdialysis to evaluate FITC-dextran encapsulated immunopegylated nanoparticles

Abstract

Context: Delivery of drugs and dyes through intact bloodbrain barrier (BBB) is extremely sought-after. A safe and reliable measurement of delivery efficacy in live animals is necessary. Objective: To investigate the brain uptake of FITC-dextran MW 4000 (FD4) by CD71/OX-26 coated nanoparticles by microdialysis sampling and fluorescence/confocal microscopy. Materials and methods: Methoxy-poly(ethylene glycol)-poly(lactide) (Met-PEG-PLA) and maleimide-poly(ethylene glycol)-poly(lactide) (Mal-PEG-PLA) nanoparticles were prepared by nanoprecipitation. The surfaces of the prepared nanoparticles were embellished with CD-71/OX-26 antibodies for brain targeting. Male Sprague Dawley rats received 0.4mg/kg FD4 and equivalent nanoparticulate formulation through lateral tail vein. Animals were euthanized 24h postadministration, after which the tissues were harvested and analyzed for FD4 concentrations. Tissues were fixed with paraformaldehyde, cryotomed to 20 m sections, and analyzed by Total Internal Reflection microscopy. Results: Particle sizes of 200±25nm and zeta potentials of -18±1 mV were obtained. FD4 concentrations, determined using in vivo brain microdialysis, were high on the first day (~360ng/mL) compared to 60ng/mL on the following 2 days. The nanoparticle treated animals showed significantly higher (p < 0.05) FD4 concentrations in the brain than pure-FD4 treated animals. Immunopegylated nanoparticles sustained and enhanced Central nervous system (CNS) concentration of hydrophilic dye for at least 3 days. Conclusion: Immunopegylated nanoparticles produce enhanced and sustained uptake of brain permeability marker FD4 relative to controls. © 2012 Informa Healthcare USA, Inc.