ApoE3 Anchored Liposomal Delivery of Rivastigmine for Brain Delivery: Formulation, Characterization, and In Vivo Pharmacokinetic Evaluation

Rivastigmine hydrogen tartrate (RHT) is an acetylcholinesterase (AChE) inhibitor used in the management of Alzheimer's disease (AD). RHT is a BCS class-I drug that undergoes significant first-pass metabolism. Permeating a hydrophilic drug through the brain remains a major challenge in brain delivery. In this study, the RHT was incorporated inside the hydrophilic core of liposomes (LPS) and then coated with the ApoE3. ApoE3-coated RHT-loaded liposomes (ApoE3-RHT-LPS) were fabricated through the thin film hydration method using DSPE-PEG. The coating of LPS with ApoE3 enhances brain uptake and improves A beta clearance. The results obtained from the physicochemical characterization demonstrated that ApoE3-RHT-LPS shows a particle size of 128.6 +/- 2.16 nm and a zeta potential of 16.6 +/- 1.19. The % entrapment efficiency and % drug loading were found to be 75% and 17.84%, respectively. The data obtained from TEM and SEM studies revealed that the particle size of the LPS was less than 200 nm. An in vitro AChE assay was performed, and the results demonstrated the AChE inhibitory potential of ApoE3-RHT-LPS. Through the intravenous route, an in vivo pharmacokinetic study of formulation displayed improved brain uptake of RHT by similar to 1.3-fold than pure RHT due to ApoE3 coating. In vivo, biodistribution studies in vital organs suggested that the biodistribution of RHT to the liver was significantly reduced (p < 0.001), signifying an increase in the drug's half-life and blood circulation time. All research findings suggested that ApoE3 coating and LPS strategy are proven effective for improving the brain uptake of RHT designed for the management of AD.