Medical Applications of Dyes: A Review of Photodynamic Therapy
David Dolphin and Sternberg, E.
Chemistry of Functional Dyes, Eds. Z. Yoshida and T. Kitao, Mita Press, Tokyo, Japan,
Ch. 12, 587-597
Mankind has incorporated dyes into ceremonies marking birth, death, war and illness throughout recorded history. Historical evidence traces the medical application of photoactivated dyes derived from plant sources to the ancient Egyptians. Their use of psoralens in combination with light for the treatment of vitiligo, a pigmentation disorder, is well documented. During the 19th century it was believed that drugs needed to be colored to be efficacious. Indeed, the discovery of sulfanilamide by Paul Ehrich vas based upon this hypothesis. This resulted in the successful treatment of syphilis and began the modern era of chemical based pharmaceuticals. Only a few years earlier the great German chemist August Wilhelm Hoffman and his English student William Perkin founded the coal-tar dye industry and the development of azo dyes. Today, three major groups of dyes are utilized in medicine. They absorb from the near ultraviolet (UV) through the visible region and into the near infrared region (IR) of the optical spectrum. They in- clude the myriad of visible dyes which are utilized for analysis of the behavior of a cell and its components, the UV absorbing psoralens which are directly utilized for the treatment of disease and the porphyrin type molecules which absorb into the near IR and like the psoralens have been found to be effective for the treatment of disease. A final class of dyes of note are the cationic chalocogenapyrulIum dyes, which absorb far into the infrared and are presently being investigated for their potential use as therapeutic agents. A review with 29 references on PhotoDynamic Therapy is presented