The interaction between cucurbit[7]uril and trimethoprim and its effect on the properties of trimethoprim

Trimethoprim (TMP) is a broad-spectrum antibacterial agent that exhibits an obvious synergistic effect when used in combination with sulfa antibiotics, but its poor solubility and other drawbacks limit its applications. Herein, the interaction between TMP and cucurbit[7]uril (Q[7]), and the effect of Q[7] on the properties of TMP were investigated using UV-vis and fluorescence spectroscopy, isothermal titration calorimetry (ITC), 1 H NMR spectroscopy and mass spectrometry. The results showed that TMP and Q[7] interacted to form a 1:1 inclusion complex (TMP@Q[7]). After interacting with TMP, Q[7] increased the solubility of TMP in an aqueous solution by 7.75-fold, effectively prolonging the release time of TMP in artificial gastroenteric juice, and plays a role in its sustained release. However, the stability and antibac-terial activity of TMP in artificial gastroenteric juice were not affected.(c) 2022 Elsevier B.V. All rights reserved.