Chitosan coated nanostructured lipid carriers for brain delivery of proteins by intranasal administration

•Design and optimization of a chitosan coated nanostructured lipid carrier (CS-NLC) with the capacity to reach the brain after being intranasally administered.•The in vitro assays demonstrated the biocompatibility of the nanocarrier, and its cellular uptake by 16HBE14o- cells.•No haemagglutination or haemolysis processes were observed when CS-NLCs were incubated with erythrocytes.•No toxicity signals appeared in the nasal mucosa of mice after the administration of CS-NLCs.•The biodistribution study of CS-NLC-DiR demonstrated an efficient brain delivery of the particles after intranasal administration.

The remarkable increase in the prevalence of neurodegenerative diseases has become a serious public health problem. Considering the lack of effective treatments to address these diseases and the difficulties in accessing the brain due to the blood–brain barrier (BBB), to attain a successful strategy to improve drug delivery to the brain, the administration route becomes a point of interest. The intranasal route provides a non-invasive method to bypass the BBB. Moreover, the development of new technologies for the protection and delivery of peptides is an interesting approach to consider. Thus, in this work, a suitable chitosan coated nanostructured lipid carrier (CS-NLC) formulation with the capacity to reach the brain after being intranasally administered was successfully developed and optimized. The optimal formulation displayed a particle size of 114 nm with a positive surface charge of +28 mV. The in vitro assays demonstrated the biocompatibility of the nanocarrier and its cellular uptake by 16HBE14o- cells. Furthermore, no haemagglutination or haemolysis processes were observed when the particles were incubated with erythrocytes, and no toxicity signals appeared in the nasal mucosa of mice after the administration of CS-NLCs. Finally, the biodistribution study of CS-NLC-DiR demonstrated an efficient brain delivery of the particles after intranasal administration. In conclusion, CS-NLC can be considered to be a safe and effective nanocarrier for nose-to-brain drug delivery; however, to obtain a higher concentration of the drug in the brain following intranasal administration, further modifications are warranted in the CS-NLC formulation.

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