The rate of chronic and acute wound healing can be delayed or impaired by a number of factors (exogenous and endogenous) and a variety of medical conditions. Examples include infection, ulceration particularly through diabetes, circulation problems associated with vascular disease, malnutrition, stress, cancer radiotherapy and/or chemotherapy, compromise of the immune system or simply due to the normal aging process. At present there is a clear need for therapeutic and cosmetic approaches that promote wound healing processes.
The literature describes the PDT use of various photosensitisers in attempts to improve wound healing. For example, Photofrin (a porphyrin, Photofrin is a trade mark of Johnson & Johnson) showed delayed wound healing in rat skin flap reconstruction (Kubler et al Lasers in surgery and Medicine (1996), 18(4), 397-405. Parekh et al concluded in Lasers in surgery and Medicine (1999), 24(5), 375-381 that a benzoporphyrin and a phthalocyanine didn't alter wound healing. Lambrects et al concluded in Photochemical & Photobiological Sciences (2005), 4(7), 503-509 that a porphyrin delayed wound healing. Hamblin concluded in Journal of infectious diseases (2003), 187(11), 1717-25 that for a photosensitiser (Poly-lysine-chlorin e6) topical PDT did not accelerate wound healing, compared with that in untreated wounds. Belmont et al in the Laryngoscope (1999), 109(6), 886-90 using Photofrin concluded that PDT has been shown to delay wound healing. Heckenkamp et al in Journal of vascular surgery, (2000), 31(6), 1168-77 concludes that local photodynamic action of methylene blue exerts a retarding effect on intimal hyperplasia (one of the natural wound healing processes).
Compounds, methods and compositions/medicaments have now been identified which address these problems and provide a basis for promoting the wound healing process.