Drug Delivery by Controlling a Supramolecular Host–Guest Assembly with a Reversible Photoswitch

Abstract

The reversibly switchable trans-chalcone/flavylium photochromic system was successfully coupled to the complexation equilibrium of a drug-cucurbit[7]uril host-guest assembly. Hence, the phototriggered release of memantine under illumination at 366 nm was observed. The process can be partially reverted through a thermally activated back reaction.

A Visible–Near‐Infrared Light‐Responsive Host–Guest Pair with Nanomolar Affinity in Water

“…Light is recognized as a superior stimulus for many applications because it allows for remote spatiotemporal control, it is orthogonal to other stimuli, and additional reagents are not required . Although different host–guest complexes formed from CBn and photoresponsive guests had been reported, most of them show binding affinities in the micromolar range or above . In particular, CB8 is known to simultaneously bind two anthracene derivatives in its cavity with high stability, accelerating their photodimerization.…”

Kinetics Inside, Outside and Through Cucurbiturils

“…[5] As presented by the same authors, irradiation of transchalcone 63 a (366 nm for one hour; solution pD = 4.4) triggers the slow formation of flavylium cation 63 b, which can then efficiently eject memantine (64) from the cavity of CB [7] (from 80 % to 10 % encapsulation). [108] Liu and Ma showed that acyclic CB[n] 65 (R = H, CH 3 ; negative at pH 7.4, see Scheme 9) can encapsulate a series of positively charged guests including berberine (6). [108] Liu and Ma showed that acyclic CB[n] 65 (R = H, CH 3 ; negative at pH 7.4, see Scheme 9) can encapsulate a series of positively charged guests including berberine (6).…”

Terpenes Show Nanomolar Affinity and Selective Binding with Cucurbit[8]uril

“…[5,6] Hence it is not a surprise that organic molecules with protonable or peralkylated heteroatoms are preferred. In general high binding constants result, which are an additional asset for the widely recognized application potential of cucurbiturils in sensing and switching, [8][9][10][11][12][13][14][15] biomolecule modification, [4,[16][17][18][19] and delivery, [14,[20][21][22][23][24][25] to name just a few examples. [7] In some cases the complexation is also entropically favored.…”