Aspirin was covalently conjugated to the primary/secondary hydroxyl groups of β-cyclodextrin in different solvents using different reagents for acylation. In pyridine, β-cyclodextrin reacted with acetylsalicylic acid chloride to produce the aspirin conjugates on the primary hydroxyl side, and in a carbonate buffer solution of N, N-dimethylformamide, β-cyclodextrin reacted with N-(2-acetoxybenzoyl)imidazole to give the aspirin conjugates on the secondary hydroxyl side.