Modulation of Photophysics and pKa Shift of the Anti‐cancer Drug Camptothecin in the Nanocavities of Supramolecular Hosts

摘要: This article reports the pK(a) shift of an anti-cancer drug, 20(S)-camptothecin (CPT), upon encapsulation into nanocavity a cucurbit[7]uril (CB7) macrocycle. Steady-state, time-resolved fluorescence and electrospray ionisation mass spectrometry (ESI-MS) studies provide evidence for formation both 1:1 2:1 (CB7⋅CPT) stoichiometries. Astonishingly, we have found that protonation CPT takes place at higher concentration macrocycle (≥50 μM) when stoichiometric complex develops. However, did not find any proof it is encased by β-cyclodextrin cavity, which has cavity size almost same as CB7. Hence, conclude electron-rich carbonyl portals CB7 important role in drug inclusion complex. Docking semi-empirical quantum chemical calculations been employed to gain insight molecular picture orientation complexes. It clearly seen from optimised structure quinoline nitrogen does reside within either cavities, rather sandwiched between two rings, therefore, experiences huge electron density exerted macrocycles. As result, shifts 1.2 6.2. Finally, controlled release achieved through introduction NaCl, rich cells, external stimulus. We hope this recognition-mediated binding mechanism can be useful activation therapeutic uses.