Novel tacrine-based acetylcholinesterase inhibitors as potential agents for the treatment of Alzheimer's disease: Quinolotacrine hybrids.

A new series of quinolotacrine hybrids including cyclopenta- and cyclohexa-quinolotacrine derivatives were designed, synthesized, and assessed as anti-cholinesterase (ChE) agents. The designed derivatives indicated higher inhibitory effect on the acetylcholinesterase (AChE) with IC50 values of 0.285-100 µM compared to butyrylcholinesterase (BChE) with IC50 values of > 100 µM. Of these compounds, cyclohexa-quinolotacrine hybrids displayed a little better anti-AChE activity than cyclopenta-quinolotacrine hybrids. Compound 8-amino-7-(3-hydroxyphenyl)-5,7,9,10,11,12-hexahydro-6H-pyrano[2,3-b:5,6-c'] diquinolin-6-one (6m) including 3-hydroxyphenyl and cyclohexane ring moieties exhibited the best AChE inhibitory activity with IC50 value of 0.285 µM. The kinetic and molecular docking studies indicated that compound 6m occupied both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of AChE as a mixed inhibitor. Using neuroprotective assay against H2O2-induced cell death in PC12 cells, the compound 6h illustrated significant protection among the assessed compounds. In silico ADME studies estimated good drug-likeness for the designed compounds. As a result, these quinolotacrine hybrids can be very encouraging AChE inhibitors to treat Alzheimer's disease. A novel series of quinolotacrine hybrids were designed, synthesized, and evaluated against AChE and BChE enzymes as potential agents for the treatment of AD. The hybrids showed good to significant inhibitory activity against AChE (0.285-100 µM) compared to butyrylcholinesterase (BChE) with IC50 values of > 100 µM. Among them, compound 8-amino-7-(3-hydroxyphenyl)-5,7,9,10,11,12-hexahydro-6H-pyrano[2,3-b:5,6-c'] diquinolin-6-one (6 m) bearing 3-hydroxyphenyl moiety and cyclohexane ring exhibited the highest anti-AChE activity with IC50 value of 0.285 µM. The kinetic and molecular docking studies illustrated that compound 6 m is a mixed inhibitor and binds to both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of AChE.

Hydrophobic ion pairing with cationic derivatives of α-, ß-, and γ-cyclodextrin as a novel approach for development of a self-nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin.

To enhance the oral bioavailability of heparin, a self-nano-emulsifying drug delivery system (SNEDDS) was developed using hydrophobic ion-pairing with cationic polymers of α-, ß-, and γ-cyclodextrins (CPCDs). Hydrophobic ion paired complexes were formed, and the recovery of heparin was determined in n-hexane and isopropyl myristate (IPM). The SNEDDSs were prepared and were optimized using D-optimal response surface methodology (RSM). The determination of the recovery of complexes in IPM revealed that in cationic α-cyclodextrin, the highest recovery was achieved at the heparin: CPCD weight ratio of 1:0.5. However, in cationic ß-cyclodextrin the highest recovery was obtained at the weight ratio of 1:4. Similar to CPßCD, for ealed that in c the highest recovery was obtained at 1:4 weight ratio. The size of optimized nano-droplets was found to be 127.00 ± 4.1, 184.00 ± 6.43, and 216.00 ± 5.43 nm; polydispersity index (PdI) values were reported as 0.372 ± 0.005, 0.163 ± 0.008, 0.236 ± 0.003; and calculated loading efficiency (LE%) were 84.60 ± 3.62, 91.06 ± 2.49, and 92.81 ± 0.70% for SNEDDS preparations incorporating cationic derivatives of α-, ß-, and γ-cyclodextrin, respectively. The in vitro release study revealed that SNEDDS preparations containing cationic γ-cyclodextrin posed the slowest release rate. Data achieved from cellular uptake study showed that the SNEDDS containing α-cyclodextrin had the highest cumulative uptake percentage after 6 h post-exposure; same results were obtained in the intestinal transport study demonstrating SNEDDS containing α-cyclodextrin posed the highest transport efficiency with Papp of 24.85 × 10-r ± 1.06 × 10-± cm.s-m.