(T1430-09-61) Rational Development of Donepezil-Curcumin Intranasal Nanotherapies for Alzheimer’s Disease

Purpose: Current Alzheimer’s Disease (AD) treatments mainly manage dementia symptoms, highlighting the pressing need for treatment strategies to retard disease progression. Both donepezil (DPZ) and curcumin (CUR) have neuroprotective effects for AD [1,2], co-delivery of which may synergistically improve the therapeutic efficacy. Intranasal nanotherapy enhances treatment efficacy by prolonging drug residence time, increasing cellular internalization, and improving bioavailability [1]. This project aims to produce intranasal nanoparticle-based DPZ-CUR dry powder formulations with the aid of Box-Behnken design for management of AD.

Methods: A Box-Behnken design (Table 1) was conducted to optimize DPZ-CUR nanosuspensions produced by a multi-inlet vortex mixer with polyvinylpyrrolidone (PVP) and α-Tocopherol polyethylene glycol succinate (TPGS) as stabilizers. The initial concentration of TPGS was fixed at 7.5 mg/mL. The particle size and polydispersity index (PDI) were measured by dynamic light scattering, while the physical stability of the nanosuspension was determined by % change in size after 6 hours. The drug loading (DL) and encapsulation efficiency (EE) were measured by HPLC assay after the centrifugal ultrafiltration [3]. Optimized nanosuspension was co-spray dried into nanoagglomerates with methylcellulose and into nano-embedded powders with mannitol, respectively. The redispersibility index (RdI) of dry powder formulations was assessed using the ratio of the particle size of the nanosuspension reconstituted from dry powder formulations to the initial particle size of freshly prepared nanosuspension before spray drying. The aerosol performance of powders was evaluated using the Alberta Idealized Nasal Inlet (AINI) with a Next Generation Impactor (NGI) at a flow rate of 15 L/min. CCK-8 cell viability assay was evaluated on RPMI 2650 and SH-SY5Y cell lines.

Results: As shown in Figure 1, all factors were significantly associated with the particle size and PDI. Factor A significantly affected particle size and % change negatively, and affected PDI positively, while interaction terms AB negatively affected all responses. The highest desirability function value of 0.948 was obtained when A = 2.7, B = 4.6 and C = 0.35, and models were validated using the optimized formulation parameters. The optimized nanosuspension exhibited a particle size of 115.7 ± 2.1 nm, a PDI of 0.151 ± 0.036, physical stability of 72 ± 0 hours, and EE of 80.10 ± 0.01% for DPZ and over 99.99% for CUR. The DLs of DPZ (6.78 ± 0.04%) and CUR (22.86 ± 0.07%) were consistent with theoretical values. Both nanoagglomerate and nano-embedded powders showed adequate RdI (1.17 ± 0.03 and 1.15 ± 0.04, respectively). No statistically significant differences were observed in the olfactory region deposition between the nanoagglomerate and nano-embedded powders (11.65 ± 2.17% and 7.36 ± 0.34%, respectively). Both formulation powders demonstrated negligible cytotoxicity on RPMI 2650 and SH-SY5Y cells at DPZ concentrations from 0.016 to 2 μM.

Conclusion: DPZ-CUR nanosuspension was successfully developed and optimized using Box-Behnken design. Both nanoagglomerate and nano-embedded dry powders demonstrated acceptable RdI, drug deposition in the olfactory region and safety. Future research will investigate ex vivo efficacy. Our findings highlight the potential of nasal delivery of DPZ-CUR dry powders as an effective treatment strategy for AD.

References: 1. Zhang, X.; Su, G.; Shao, Z.; Chan, H. W.; Li, S.; Chow, S.; Tsang, C. K.; Chow, S., Rational Development of Fingolimod Nano-embedded Microparticles as Nose-to-Brain Neuroprotective Therapy for Ischemic Stroke. 2024.
2. Salem, H. F.; Aboud, H. M.; Abdellatif, M. M.; Abou-Taleb, H. A., Nose-to-Brain Targeted Delivery of Donepezil Hydrochloride via Novel Hyaluronic Acid-Doped Nanotransfersomes for Alzheimer's Disease Mitigation. J Pharm Sci 2024, 113 (7), 1934-1945.
3. Chan, H. W.; Lee, H. W.; Chow, S.; Lam, D. C. L.; Chow, S. F., Integrated continuous manufacturing of inhalable remdesivir nanoagglomerate dry powders: Design, optimization and therapeutic potential for respiratory viral infections. Int J Pharm 2023, 644, 123303.

Acknowledgements: This research was supported by the University of Hong Kong (Project Number: 109001171), the Health Medical Research Fund (Project Number: 21223381) from the Health Bureau, and the InnoHK initiative of the Innovation and Technology Commission of the Hong Kong Special Administrative Region Government.

Table 1. A three-factor Box-Behnken design for evaluation of response surface of DPZ-CUR nanosuspension formulation.

Figure 1. Pareto charts and normal probability plots of the standardized effects. Pareto charts of standardized effects of factors and their interactions on (a) particle size (Y1), (c) PDI (Y2) and (e) % change in size after 6 h (Y3), and normal probability plots of standardized effects of factors and their interactions on (b) particle size (Y1), (d) PDI (Y2) and (f) % change in size after 6 h (Y3). In the Pareto charts, factors and their interactions that cross the vertical dotted line have statistically significant effects. Factors and their interactions with red square labels have statistically significant effects in the normal probability plots.