Complexation was investigated as an approach to enhance the entrapment of the cationic neurotherapeutic drug, galantamine hydrobromide (GH) into cationic chitosan nanoparticles (CS-NPs) for Alzheimer's disease management intranasally. Biodegradable CS-NPs were selected due to their low production cost and simple preparation. The effects of complexation on CS-NPs physicochemical properties and uptake in rat brain were examined. Placebo CS-NPs were prepared by ionic gelation, and the parameters affecting their physicochemical properties were screened. The complex formed between GH and chitosan was detected by the FT-IR study. GH/chitosan complex nanoparticles (GH-CX-NPs) were prepared by ionic gelation, and characterized in terms of particle size, zeta potential, entrapment efficiency, in vitro release and stability for 4 and 25 °C for 3 months. Both placebo CS-NPs and GH-CX-NPs were visualized by transmission electron microscopy. Rhodamine-labeled GH-CX-NPs were prepared, administered to male Wistar rats intranasally, and their delivery to different brain regions was detected 1 h after administration using fluorescence microscopy and software-aided image processing. Optimized placebo CS-NPs and GH-CX-NPs had a diameter 182 and 190 nm, and a zeta potential of +40.4 and +31.6 mV, respectively. GH encapsulation efficiency and loading capacity were 23.34 and 9.86%, respectively. GH/chitosan complexation prolonged GH release (58.07% ± 6.67 after 72 h), improved formulation stability at 4 °C in terms of drug leakage and particle size, and showed insignificant effects on the physicochemical properties of the optimized placebo CS-NPs (p > 0.05). Rhodamine-labeled GH-CX-NPs were detected in the olfactory bulb, hippocampus, orbitofrontal and parietal cortices. Complexation is a promising approach to enhance the entrapment of cationic GH into the CS-NPs. It has insignificant effect on the physicochemical properties of CS-NPs. GH-CX-NPs were successfully delivered to different brain regions shortly after intranasal administration suggesting their potential as a delivery system for Alzheimer's disease management.

Purpose: Nasal galantamine hydrobromide (GH)/chitosan complex nanoparticles (CX-NP2) could have an improved therapeutic potential for managing Alzheimer’s disease (AD). The current study aimed to investigate if the complexation reaction between GH and chitosan altered the pharmacological and toxicological profiles of the parent drug; GH. Methods: The nasal administration of CX-NP2 to male Wistar rats for 12 consecutive days was compared to negative control group, and oral and nasal GH solutions treated groups in 3 mg/kg daily GH dose. Brain acetylcholinesterase (AChE) protein level and activity were assessed. The in vivo toxicity of CX-NP2 was evaluated via monitoring the clinical signs throughout the study. Histopathological examination of brain sections was performed. The intracellular localization of CX-NP2 within brain neurons was investigated using transmission electron microscopy. Results: GH/chitosan complexation did not negatively alter the pharmacological efficiency of GH. Intriguingly, nasal CX-NP2 exhibited a significant decrease of AChE protein level and activity in rat brains compared to the oral and nasal GH solutions. No toxicity signs or histopathological manifestations were noticed. The nanoparticles were found intracellularly in the brain neurons. Conclusion: The pharmacological efficacy and in vivo safety of nasal CX-NP2 confirm their promising potential to contribute to the management of AD intranasally.