Spiropyrans for light-controlled drug delivery.

The supramolecular assembly of acetylsalicylic acid to a merocyanine-Zn complex translates into a photo-controllable drug delivery system. Herein, we present the synthesis and spectroscopic analysis of a three-component assembly combining a spiropyran derivative, a zinc(ii) cation, and acetylsalicylic acid. The ON/OFF system can be modulated by safe and easily affordable stimuli, for the specific delivery of more than one active compound. Our results confirm the formation of a ternary system in solution, where the behaviour is dominated by photo-induced responses, and pave the way for the use of such smart platforms for medicinal chemistry purposes.