Development of <scp>pH</scp>‐Responsive Hydrogel Excipient From Karaya Gum for Improved Oral Delivery of Donepezil Hydrochloride in Alzheimer's Disease Treatment

ABSTRACT The present study focused on fabricating an efficient excipient for donepezil HCl from karaya gum as the base material. The karaya gum was grafted and crosslinked with N ‐isopropyl acrylamide and N , N′ ‐methylene(bis)acrylamide, respectively, using microwave. The successful fabrication of the resulting hydrogel was confirmed and characterized by FTIR, FESEM, and TGA analyses. Remarkably, the synthesized gel exhibited distinct swelling behavior in different pH mediums ranging from 1.2 to 13. As expected, the gel exhibited an impressive 96% release of donepezil, a widely used hydrophilic drug for treating Alzheimer's disease, in a buffer solution of pH 1.2, within a 48‐h timeframe. Kinetic studies further revealed that drug release from the gel aligns with the Higuchi model. Cytotoxicity studies using Drosophila melanogaster as a model system showed the biocompatible nature of the excipient. This characteristic highlights its potential application as a drug carrier for the oral delivery of Donepezil HCl in treating Alzheimer's disease.