title: Sustained release of dexamethasone from hydrophilic matrices using PLGA nanoparticles for neural drug delivery.
abstract: The release of the anti-inflammatory agent dexamethasone (DEX) from nanoparticles of poly(lactic-co-glycolic acid) (PLGA) embedded in alginate hydrogel (HG) matrices was investigated. DEX-loaded PLGA nanoparticles were prepared using a solvent evaporation technique and were characterized for size, drug loading, and in-vitro release. The crosslinking density of the HG was studied and correlated with drug release kinetics. The amount of DEX loaded in the nanoparticles was estimated as approximately 13 wt%. The typical particle size ranged from 400 to 600 nm. The in-vitro release of DEX from NPs entrapped in the HG showed that 90% of the drug was released over 2 weeks. The impedance of the NP-loaded HG coatings on microfabricated neural probes was measured and found to be similar to the unmodified and uncoated probes. The in-vivo impedance of chronically implanted electrodes loaded with DEX was maintained at its initial level, while that of the control electrode increased by 3 times after about 2 weeks after implantation until it stabilized at approximately 3 MOmega. This improvement in performance is presumably due to the reduced amount of glial inflammation in the immediate vicinity of the DEX-modified neural probe.
authors.affiliation: Biomedical Engineering, University of Michigan, Michigan 48109-2136, USA.
authors.forename: Dong-Hwan
authors.initials: DH
authors.lastname: Kim
authors.forename: David C
authors.initials: DC
authors.lastname: Martin
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001921:Brain / Q000187:drug effects*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000737:chemistry*; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D004343:Drug Implants / Q000737:chemistry*; D006168:Guinea Pigs; D057927:Hydrophobic and Hydrophilic Interactions; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D004343:Drug Implants; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D003907:Dexamethasone