SYNTHESIS, CHARACTERIZATION, IN-SILICO, AND PHARMACOLOGICAL EVALUATION OF NEW 2-AMINO-6-TRIFLUOROMETHOXY BENZOTHIAZOLE DERIVATIVES

Alzheimer's disease (AD), a relentless neurodegenerative disorder, is still waiting for safer profile drugs, risk factors affecting AD's pathogenesis include aβ accumulation, tau protein hyperphosphorylation, and neuroinflammation. This research aimed to synthesize 2-amino-6‑trifluoromethoxy benzothiazole schiff bases. Synthesis was straightforward, combining the riluzole skeleton with compounds containing the azomethine group. Schiff bases synthesized were characterized spectroscopically using proton NMR (¹H NMR), and FTIR. In-vivo biological evaluation against scopolamine-induced neuronal damage revealed that these newly synthesized schiff bases were effective in protecting neurons against neuroinflammatory mediators. In-vitro results revealed that these compounds had remarkable potential in improving the anti-oxidant levels. It downregulated glutathione (GSH), glutathione S-transferase (GST), catalase levels, and upregulated lipid peroxidation (LPO) levels. Immunohistochemical studies revealed that groups treated with the newly synthesized schiff bases had reduced expression of inflammatory mediators such as cyclooxygenase 2 (COX-2), JNK, tumor necrosis factor (TNF-α), nuclear factor kappa B (NF-kB) in contrast to the disease group. Moreover, molecular docking studies on these compounds also showed that they possessed a better binding affinity for above mentioned inflammatory mediators. The results of these studies showed that 2-amino-6-trifluoromethoxy benzothiazole schiff bases are remarkably effective against oxidative stress-mediated neuroinflammation.

Development and optimization of Riluzole-loaded biodegradable nanoparticles incorporated in a mucoadhesive in situ gel for the posterior eye segment

Riluzole-loaded PLGA nanoparticles (RLZ-NPs) were developed to improve the biopharmaceutical profile of RLZ after ocular administration. Moreover, RLZ-NPs were dispersed in an in situ gelling system (RLZ-NPs-Gel) for topical administration as a potential neuroprotective strategy against glaucoma. Formulations were optimized using the design of experiments approach. Characterization of the physicochemical and rheological properties, as well as interaction studies were carried out. To ensure RLZ-NPs-Gel ocular safety, the irritant potential was also evaluated in vitro and in vivo. Moreover, in vivo ocular biodistribution was also undertaken. Optimized RLZ-NPs showed an average size below 200 nm, an encapsulation efficiency greater than 90% and a negative surface charge. Interaction studies of RLZ-NPs showed that RLZ was dispersed in the polymeric matrix. RLZ-NPs-Gel possess a pseudoplastic behavior and a medium-low post-gelling viscosity to avoid discomfort after ocular application. Simultaneously, RLZ-NPs-Gel were able to increase RLZ-NPs contact with the ocular surface. Both formulations demonstrated the ability to be distributed in the posterior eye segment after 24 h of their application obtaining a more delayed distribution for RLZ-NPs-Gel. Therefore, a novel in situ gelling system able to disperse RLZ-NPs has been successfully developed as innovative neuroprotective strategy for potential topical treatment of glaucoma.

Verapamil and riluzole cocktail liposomes overcome pharmacoresistance by inhibiting P-glycoprotein in brain endothelial and astrocyte cells: A potent approach to treat amyotrophic lateral sclerosis

Riluzole is currently one of two approved medications for the treatment of amyotrophic lateral sclerosis (ALS). However, brain disposition of riluzole, as a substrate of P-glycoprotein (P-gp), is limited by the efflux transporters at the blood-brain barrier (BBB). We propose to develop a liposomal co-delivery system that could effectively transport riluzole to brain cells by reducing efflux pumps with a P-gp inhibitor, verapamil. Riluzole and verapamil cocktail liposomes were prepared by lipid film hydration. The average particle size of cocktail liposomes was 194.3 ± 6.0 nm and their polydispersity index (PDI) was 0.272 ± 0.017. The encapsulation efficiencies of verapamil and riluzole in the cocktail liposomes were 86.0 ± 1.4% and 85.6 ± 1.1%, respectively. The drug release from cocktail liposomes after 8 h in PBS at 37 °C was 78.4 ± 6.2% of riluzole and 76.7 ± 3.8% of verapamil. The average particle size of liposomes did not show significant changes at 4 °C after three months. Verapamil cocktail liposomes inhibited P-gp levels measured by western blotting in dose and time-dependent manners in brain endothelial bEND.3 cells. Increased drug efflux transporters were detected in bEND.3 and astrocytes C8D1A cells, promoted by tumor necrosis factor (TNF-α) or hydrogen peroxide (H₂O₂). Restored accumulations of riluzole and fluorescent dye rhodamine 123 were observed in bEND.3 cells after treatments with cocktail liposomes. It indicated that inhibitory potential of co-delivery liposome system towards P-gp could mediate the transport of both P-gp substrates. Verapamil and riluzole co-loaded liposomes may be used to overcome pharmacoresistance of riluzole for improving ALS therapy.