For a comprehensive overview on the ideas and principles behind photopharmacology, visit our new dedicated website at


Figure 1. Reprinted with permission from J. Am. Chem Soc. 2014, 136, 21782191. Copyright 2014 American Chemical Society

Photopharmacology is a is a recently-defined method for using light to control living systems. It relies on the incorporation of molecular photoswitches, for example azobenzenes, into the structure of drugs. Light irradiation results in the change in properties of the photoswitch-modified drug, such as shape, lipophilicity, dipole moment, etc. These changes are translated into difference in pharmacodynamic and pharmacokinetic properties of the drug, which results in the difference in bioactivity between the two photoisomeric forms.

Figure 2. Reprinted with permission from Nat. Chem. 2013, 5, 924928. Copyright 2013 Nature Publishing Group

This concept can be exemplified by our recent report on antibiotics with photocontrolled activity (Figure 2). In the thermodynamically stable trans-form, the biactive compound shows low antibacterial activity and, in principle, would not cause the emergence of bacterial resistance in the environment. However, when irradiated by light prior to administration, the compound is temporally activated, after which it inactivates again within a few hours. This highlights the opportunities offered by photopharmacology for solving drug-related problems.