Chlorotoxin-modified stealth liposomes encapsulating levodopa for the targeting delivery against the Parkinson's disease in the MPTP-induced mice model

Chlorotoxin (ClTx), originally isolated from scorpion venom of Leiurus quinquestriatus, is a 36-amino acid peptide and specifically binds to the brain gliomas and proliferating vascular endothelial cells. In this paper, it was first used to establish the ClTx-modified stealth liposomes (ClTx-LS) encapsulating levodopa (LD) for the targeting drug delivery against the Parkinson's disease (PD). After the DSPE-PEG-ClTx was synthesized and identified, the ClTx-LS system was prepared and characterized. Its targeting capability was studied in vitro and in vivo, and finally its anti-PD activity was evaluated, with non-modified liposomes (LS) as control. It was demonstrated through flow cytometry and confocal microscopy that ClTx modification highly facilitated the uptake of LS by brain microvascular endothelial cells in vitro. After intraperitoneal injection to mice, the active targeting system loaded with LD significantly increased the distribution of dopamine and dihydroxyphenyl acetic acid, the metabolites of LD, in the substantia nigra and striata. In the methyl-phenyl-tetrahydropyridine (MPTP)-induced PD mice model, LD-loaded ClTx-LS significantly attenuated the serious behavioral disorders and diminished the MPTP-induced loss of tyrosine hydroxylase-positive dopaminergic neurons. In conclusion, ClTx-modified LS might serve as a targeting delivery system to transport more drugs into the brain for a better PD therapy.