Potential therapeutic effect of nanobased formulation of rivastigmine on rat model of Alzheimer's disease

Manal Fouad Ismail,1 Aliaa Nabil ElMeshad,2 Neveen Abdel-Hameed Salem31Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt; 3Department of Narcotics and Ergogenic Aids and Poisons, National Research Center, Giza, EgyptBackground: To sustain the effect of rivastigmine, a hydrophilic cholinesterase inhibitor, nanobased formulations were prepared. The efficacy of the prepared rivastigmine liposomes (RLs) in comparison to rivastigmine solution (RS) was assessed in an aluminium chloride (AlCl3)-induced Alzheimer’s model.Methods: Liposomes were prepared by lipid hydration (F1) and heating (F2) methods. Rats were treated with either RS or RLs (1 mg/kg/day) concomitantly with AlCl3 (50 mg/kg/day).Results: The study showed that the F1 method produced smaller liposomes (67.51 ± 14.2 nm) than F2 (528.7 ± 15.5 nm), but both entrapped the same amount of the drug (92.1% ± 1.4%). After 6 hours, 74.2% ± 1.5% and 60.8% ± 2.3% of rivastigmine were released from F1 and F2, respectively. Both RLs and RS improved the deterioration of spatial memory induced by AlCl3, with RLs having a superior effect. Further biochemical measurements proved that RS and RLs were able to lower plasma C-reactive protein, homocysteine and asymmetric dimethylarginine levels. RS significantly attenuated acetylcholinesterase (AChE) activity, whereas Na+/K+-adenosine triphosphatase (ATPase) activity was enhanced compared to the AlCl3-treated animals; however, RLs succeeded in normalization of AChE and Na+/K+ ATPase activities. Gene-expression profile showed that cotreatment with RS to AlCl3-treated rats succeeded in exerting significant decreases in BACE1, AChE, and IL1B gene expression. Normalization of the expression of the aforementioned genes was achieved by coadministration of RLs to AlCl3-treated rats. The profound therapeutic effect of RLs over RS was evidenced by nearly preventing amyloid plaque formation, as shown in the histopathological examination of rat brain.Conclusion: RLs could be a potential drug-delivery system for ameliorating Alzheimer's disease.Keywords: rivastigmine, Alzheimer’s disease, liposomes, rats, gene expressio

Nanoliposomal Growth Hormone and Sodium Nitrite Release from Silicone Fibers Reduces Thrombus Formation Under Flow

 Biocompatibility of artificial lungs can be improved by endothelialization of hollow fibers. Bioavailability of growth-inducing and anti-thrombotic agents on the hollow fiber–blood interface inhibits thrombosis. We investigated if nanoliposomal growth-inducing growth hormone (nGH) and anti-thrombotic sodium nitrite (nNitrite) incorporation into collagen-coating on silicone hollow fibers improves blood biocompatibility by increasing endothelial cell growth and nitrite bioavailability under flow. Nitrite production rate was assessed under varying flow conditions. Finite element (FE) modeling was used to simulate nitrite transport within the parallel-plate flow chamber, and nitrite bioavailability on the fiber–blood interface at 1–30 dyn/cm2 shear stress. Endothelial cell number on fibers coated with nNitrite-nGH-collagen conjugate was 1.5-fold higher than on collagen-coated fibers. For collagen-coated fibers, nitrite production reached a maximum at 18 dyn/cm2 shear stress. When fibers were coated with nNitrite-nGH-collagen conjugate, nitrite production increased continuously by increasing shear stress. FE modeling revealed that nitrite concentrations at the fiber–blood interface were affected by shear stress-induced nitrite production, and diffusion/convection-induced nitrite removal. Highest nitrite concentrations and lowest thrombus deposition were observed on fibers coated with nNitrite-nGH-collagen conjugate exposed to 6–12 dyn/cm2 shear stress. In conclusion, our results suggest that nNitrite-nGH-Col conjugate coatings promote endothelialization of silicone hollow fibers in biohybrid artificial lungs.</p