Combined Dopamine and Grape Seed Extract-Loaded Solid Lipid Nanoparticles: Biological Evaluation.

Parkinson's disease (PD) is a common brain disorder affecting millions of people worldwide. The precise mechanisms that cause this disease remain to be identified but oxidative stress is one of the contributors to dopaminergic neuron loss in Parkinson's disease. In the present study formulated solid lipid nanoparticles (SLNs) were investigated combining the neurotransmitter dopamine (DA) and the antioxidant grape seed-derived pro-anthocyanidins (grape seed extract, GSE) with the aim reduce the PD-related oxidative stress due to the synergic effect with DA to enhance its brain bioavailability. Three types of nanoparticles were used: DA SLNs co-encapsulating GSE, GSE adsorbing DA-SLNs and DA-FITC-SLNs co-encapsulating GSE. The particle size, PDI and zeta potential were measured in each sample and Transmission electron microscopy (TEM) was adopted to investigate the nanoparticle morphology at the dried state. In vitro studies were carried to cytotoxicity assessment in Olfactory Ensheathing cells (OECs) and in SH-SY5Y and flow cytometry studies evidencing higher uptake when GSE was co-encapsulated rather than adsorbed onto the particles. Ex vivo permeation studies were carried out through excised nasal porcine mucosa using a vertical Franz cell confirmed the permeation of DA from both SLNs.