Modulation of experimental Alzheimer's disease in rats through donepezil-loaded CSF implant

Alzheimer's disease (AD) is a growing challenge worldwide, with current treatments largely symptomatic and limited. The current study aimed to introduce coated nanoporous membranes for localized drug delivery of donepezil, combining both antifouling activity and sustained drug release, unlike traditional Alzheimer's treatments that rely on systemic administration. Nanoporous membranes were prepared by electrochemical anodization, coated with Polymethyl methacrylate (PMMA) or a PMMA/polyurethane (PU) mixture to mitigate biofouling. The fabricated nanoporous membranes before and after coating were characterized using SEM/EDX, FTIR, BET, and contact angle measurements. In vitro drug release and release kinetics were studied in artificial cerebrospinal fluid (ACSF). Coated and donepezil loaded membranes were implanted on the dura surface in Wistar rats AD model via intracerebral streptozotocin (STZ) injection. The activity was evaluated on behavioral, biochemical and histological levels. PMMA enhanced membrane hydrophobicity (contact angle increased from 62.8° to 79°) and sustained drug release over 7 days, making it the preferred coating. The PMMA membrane demonstrated a reduction in beta-amyloid levels without being loaded with donepezil, while the donepezil-loaded membrane showed cognitive function improvement in Morris water maze and Y-maze. Acetylcholinesterase activity was elevated after STZ-induction of AD and got ameliorated by the membranes implantation. Brain-Derived Neurotrophic Factor (BDNF) was lowered by STZ, while increased in treated animals. Histological examination revealed the neuronal regeneration after donepezil-loaded PMMA coated membrane. These findings suggest that coated nanoporous membranes are promising systems for localized active donepezil drug delivery for AD-like symptoms modulation in STZ-induced AD model, warranting further validation in other AD paradigms.