Optimized Chitosan–Lecithin Nanocarriers for Nose-to-Brain Delivery of Dalfampridine in Multiple Sclerosis: Box–Behnken Design Optimization, and Toxicity Evaluation

Abstract
Purpose This research aims to develop Nose-to-Brain Delivery of Dalfampridine (4-Aminopyridine) Chitosan–Lecithin
Nanoparticles (DFP-CSLCNPs) to improve DFP delivery to the Central Nervous System in multiple sclerosis (MS).
Methods In silico molecular docking studies were performed to evaluate drug-target interactions. Nanoparticles were formulated using a chitosan-lecithin system and optimized through a Box-Behnken experimental design. Key parameters such
as particle size, zeta potential, and entrapment efficiency were analyzed. Ex vivo permeation studies were performed using
excised nasal mucosa.
Results In-silico docking confirmed CNS relevance, with the strongest binding to 6H24 (−11.2 kcal/mol) and favourable
Swiss ADME properties. DFP-CSLCNPs were optimized using a 3-factor Box–Behnken experimental design, which predicted an optimal formulation with a particle size of approximately 142 nm, zeta potential of +24 mV, and entrapment
efficiency exceeding 80%, supported by statistically significant quadratic models (R² = 0.9759–0.9878). The optimized formulation (F13) was subsequently prepared and experimentally validated, exhibiting a particle size of 182.8±44.2 nm, PDI
of 0.36±0.01, and zeta potential of +30.1 mV, confirming nanoscale dimensions and electrostatic stability. In vitro release
demonstrated sustained kinetics over 24 h, following Korsmeyer–Peppas (R² = 0.9699, n=0.4183; Fickian diffusion). Ex
vivo across excised nasal mucosa, DFP-CSLCNPs achieved higher cumulative permeation (1047.01 vs. 611.46 µg/cm²),
greater flux Jss (68.18±3.41 vs. 37.22±1.86 µg/cm²·h), and higher Papp (68.16±0.36 vs. 37.24±2.12×10⁻³ cm/h) than
plain solution. Safety evaluations indicated no clinical toxicity over 28 days in Wistar rats.
Conclusion The optimized DFP-CSLCNPs show promise as a safe and effective formulation for intranasal nose to brain
targeting of potassium channel blockers for the management of MS.
Keywords Dalfampridine · Nanoparticles · Nose to brain targeting · Multiple sclerosis · Chitosan-lecithin · Safety
evaluation