Developing a sensitiser from laboratory to a clinical formulation

Numerous photoactivatable dyes have been proposed as photodynamic therapy (PDT) candidates during the past few years. Very few will ever graduate to approved drug status. Critical issues exist post-research which can be factored into the selection of suitable photosensitizers for development and substantially enhance prospects of success. Examples are provided by the novel porphycene family of synthetic dyes. Non-research factors such as patents, regulatory agencies and finance require early consideration. Porphycene photosensitizers have been designed chemically to ensure purity, avoid isomers, offer rapid metabolism, minimize phototoxicity and enhance target tissue selectivity while addressing key issues of safety, efficacy and economics in the development of a topically applied photosensitizer for dermatological disease.