Intranasal Niosomal In Situ Gel As A Novel Strategy for Improving Citicoline Efficacy and Brain Delivery in Treatment of Epilepsy: In Vitro and Ex Vivo Characterization and In Vivo Pharmacodynamics Investigation

The high hydrophilicity of citicoline and its rapid metabolism are the two main obstacles hindering intact molecules from passing the blood-brain barrier. This study aimed to formulate citicoline-loaded niosomes (CTC NSMs) for efficient brain delivery via the intranasal route to improve management of epilepsy. CTC NSMs were formulated via thin-film hydration method, optimized using d-optimal design, and characterized for entrapment efficiency, vesicle size, drug release, and cumulative amount permeated. The entrapment efficiency ranged from 19.44 to 61.98% with sustained drug release, and the vesicle size ranged from 125.4 to 542.5 nm with enhanced drug permeation. Cholesterol: Span ratio of 1:1.19 and cholesterol amount of 20 mg were predicted to produce optimal characteristics. Subsequently, the optimized formulation permeation confirmed a high nasal penetration using confocal laser scanning microscopy (CLSM). Afterward, the optimized CTC NSM formulation was integrated into in situ gel to boost the residence time in the nasal cavity. Additionally, Computed Tomography (CT) was performed by labeling the optimized formulation with gold nanoparticles (GNPs) to assess brain uptake and cellular translocation after intranasal administration of CTC. Furthermore, the protection against pentylenetetrazole-induced generalized seizures and mortality were determined in rats and compared with the oral drug solution at the exact dosage. The in vivo results revealed that a low dose of CTC NSM in situ gel had a powerful protective effect with delayed the latency for the start of convulsions. Collectively, NSM in situ gel is a potentially valuable intranasal drug delivery system that can boost the efficacy of CTC in epilepsy management.