Most free drugs that cross the bloodââ?¬â??brain barrier are characterized by high liposolubility, but they often have limited clinical\napplications because of poor dissolution and poor bioavailability. In this study, we prepared donepezil drug-loaded\nnanoparticles (DZP) with cholesterol-modified pullulan (CHP) as the nanocarrier (DZP-CHP) and surface modified the drugloaded\nnanoparticles to improve the water solubility of donepezil while enhancing its targeting and sustained release. We\ndetermined the drug loading and encapsulation efficiency of DZP-CHP nanoparticles at different feed ratios. The mean Ã?± SD\ndrug loading and entrapment efficiency were high: 13.52 Ã?± 2.03 and 86.54 Ã?± 1.31. On dynamic light-scattering measurement,\nmean Ã?± SD particle size was 260.7 Ã?± 1.76 nm, polydispersity index 0.123 Ã?± 0.004, and zeta potential âË?â??5.75 Ã?± 0.64 mV. DZP-CHP\nnanoparticles prepared with the optimal feed ratio (DZP : CHP= 1 : 5) were coated with polysorbate 80, and the adsorption\nprocess was determined by isothermal titration calorimetry. We found good affinity between polysorbate 80 and DZP-CHP,\nwith mean Ã?± SD coverage 2.7 Ã?± 0.372. The mean Ã?± SD drug loading and entrapment efficiency of polysorbate 80-emulsified\nDZP-CHP nanoparticles were 8.25 Ã?± 1.80 and 91.28 Ã?± 4.57, respectively, and the proportion of drug released by 72 h was 42.71%.\nCompared to DZP-CHP alone, PS-DZP-CHP can enhance the release of donepezil.
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