The synthesis of the aspirin-cysteine conjugate was performed using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. First, cysteine and aspirin were activated in separate reactions by reacting it with EDC and NHS in dimethyl sulfoxide (DMSO) at room temperature for 2 hours. The activated cysteine and aspirin were then combined in DMSO and stirred at room temperature for 24 hours under nitrogen atmosphere. The EDC method creates a thioester bond between the carboxyl group of the aspirin and the thiol group of the cysteine through the activation of the carboxyl group by EDC, which generates an O-acylisourea intermediate that can react with the nucleophilic thiol group of the cysteine. The resulting aspirin-cysteine conjugate was purified by reverse-phase high-performance liquid chromatography (HPLC) using a C18 column and eluting with a gradient of acetonitrile and water containing 0.1% trifluoroacetic acid. The purity of the conjugate was also confirmed with cartridge-based HPLC using a C18 cartridge and eluting with a gradient of acetonitrile and water containing 0.1% trifluoroacetic acid. The identity of the conjugate was confirmed using nuclear magnetic resonance (NMR) spectroscopy, which showed the successful linkage of aspirin and cysteine through a thiol-cleavable linker. The yield of the conjugate was determined by UV-Vis spectroscopy at 280 nm and found to be approximately 60%.