Manipulation of Lipid Nanocapsules as an Efficient Intranasal Platform for Brain Deposition of Clozapine as an Antipsychotic Drug

Abstract

Background/objectives: The blood–brain barrier (BBB) significantly limits the treatment of central nervous system disorders, such as schizophrenia, by restricting drug delivery to the brain. This study explores the potential of intranasal clozapine-loaded lipid nanocapsules (IN LNCsClo) as a targeted and effective delivery system to the brain. Methods: LNCsClo were prepared using the phase inversion technique and characterized in terms of size, zeta potential, entrapment efficiency (EE%), and in vitro drug release. The pharmacokinetic, safety, and pharmacodynamic effects of LNCsClo were then evaluated in a rat model through intranasal (IN) administration and compared with those of oral and intravenous (IV) Clo solutions. Results: LNCsClo were prepared using a phase inversion technique, resulting in a nanocarrier with a particle size of 28.6 ± 3.6 nm, homogenous dispersion, and high EE% (84.66 ± 5.66%). Pharmacokinetic analysis demonstrated that IN LNCsClo provided enhanced Clo brain bioavailability, rapid CNS targeting, and prolonged drug retention compared to oral and intravenous routes. Notably, the area under the curve (AUC) for brain concentration showed more than two-fold and eight-fold increases with LNCsClo, compared to IV and oral solutions, respectively, indicating improved brain-targeting efficiency. Safety assessments indicated that LNCsClo administration mitigated Clo-associated metabolic side effects, such as hyperglycemia, insulin imbalance, and liver enzyme alterations. Additionally, pharmacodynamic studies showed that LNCsClo significantly improved antipsychotic efficacy and reduced schizophrenia-induced hyperactivity, while preserving motor function. Conclusions: These results highlight the potential of IN LNCsClo as a novel drug delivery system, offering improved therapeutic efficacy, reduced systemic side effects, and better patient compliance in the treatment of schizophrenia and potentially other CNS disorders.