Construction of an intranasal drug delivery system with hypothalamus‐targeting nanoparticles

Dysfunction of the hypothalamus is associated with endocrine imbalances, growth abnormalities, and reproductive disorders. However, there is a lack of targeted treatment strategies focused on the hypothalamus. In this study, we constructed a multifunctional nanocarrier system (S@ANP) to directly target the hypothalamic neurokinin receptor 3 (NK3R) via an intranasal delivery strategy. This system could overcome the primary obstacles in drug delivery for hypothalamus‐related diseases. Under the guidance of a modified (Trp7, β‐Ala8)‐neurokinin A (4‐10) peptide with cysteine, nanoparticles encapsulated with SB222200, an NK3R inhibitor, were found to readily penetrate hypothalamic cells with substantial loading capacity, encapsulation efficiency, and sustained release in vitro. Moreover, intranasal delivery represents an optimal delivery strategy that allows for a significant reduction in oral dosage and enables nanoparticles to bypass the blood‒brain barrier and target relevant parts of the brain. The mucolytic agent N‐acetyl‐L‐cysteine (NAC) was loaded into the nanoparticles (S@ANP + NAC) to increase mucosal solubility and intranasal delivery efficiency. In vivo evaluations showed that S@ANP + NAC could effectively target the hypothalamus and modulate NK3R‐regulated hypothalamic functions in mice. Due to its high hypothalamic targeting efficiency and low toxicity, this intranasal nanoparticle drug delivery system may serve as a potential strategy for precision therapy of hypothalamic disorders.