Interaction of Cucurbit[n]uril(n=7,8) with Sildenafil Citrate Using ~1H NMR
The host-guest chemistry of systems containing Sildenafil Citrate(denoted as SCT) and cucurbit[n]uril(denoted as CB[n],n=7,8) was investigated by 1H NMR,ESI-MS,IR,and UV-vis spectra.The results revealed that the sildenafil citrate guest and CB[n](n=7,8) host could form a stable 1 ∶ 1(molar ratio) inclusion complex,in which the position of CB[n](n=7,8) was different due to the size of their cavity.The inclusion constant of sildenafil citrate with CB[7] and CB[8] was 958 L/mol and 1530 L/mol,respectively.The binding constant which located from 102 L/mol to 103 L/mol indicates that CB[7] and CB[8] could be used as a potential slow-released agent.