Chitosan-coated liposome dry-powder formulations loaded with ghrelin for nose-to-brain delivery.

The nose-to-brain delivery of ghrelin loaded in liposomes is a promising approach for the management of cachexia. It could limit the plasmatic degradation of ghrelin and provide direct access to the brain, where ghrelin's specific receptors are located. Anionic liposomes coated with chitosan in either a liquid or a dry-powder formulation were compared. The powder formulation showed stronger adhesion to mucins (89 ± 4% vs 61 ± 4%), higher ghrelin entrapment efficiency (64 ± 2% vs 55 ± 4%), higher enzymatic protection against trypsin (26 ± 2% vs 20 ± 3%) and lower ghrelin storage degradation at 25 °C (2.67 ± 1.1% vs 95.64 ± 0.85% after 4 weeks). The powder formulation was also placed in unit-dose system devices that were able to generate an appropriate aerosol characterized by a Dv50 of 38 ± 6 µm, a limited percentage of particles smaller than 10 µm of 4 ± 1% and a reproducible mass delivery (CV: 1.49%). In addition, the device was able to deposit a large amount of powder (52.04% w/w) in the olfactory zone of a 3D-printed nasal cast. The evaluated combination of the powder formulation and the device could provide a promising treatment for cachexia.