Phototriggered release of photolabile drugs via two-photon absorption-induced cleavage of polymer-bound dicoumarin



7-(tert-Butyldimethylsiloxy)-7′-(methacryloxy)dicoumarin (TBS-Cum-D-MA) is introduced as a versatile polymerizable and photocleavable linker system for drug attachment to acrylic polymers. Following the copolymerization of the TBS-Cum-D-MA with monomeric methylmethacrylate, a model drug chlorambucil was attached in a simple reaction. Phototriggered drug release via single- and two-photon absorption induced cycloreversion of the cyclobutane of the dicoumarin part was investigated. The bound drug chlorambucil is sensitive to UV light being required for single-photon induced cleavage of the dicoumarin linker and decomposes upon UV exposure. However, under the conditions of two-photon absorption induced drug release, no photodegradation of chlorambucil was observed. As the only effective two-photon absorber in the molecule is the cyclobutane structure, even high energies of visible light do not cause any degradation of the drug. This suggests that two-photon-triggered drug release may be successfully accomplished even with UV light sensitive drugs. The concept introduced here may be a powerful strategy in polymer design for photocontrolled drug delivery devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2443–2452, 2007