Experiments on Laser Mediated Photosensitization: Preclinical Evaluation of Mono-1-Aspartyl Chlorin e6 (NPe6)
A renewed interest in the synthesis and evaluation of “second generation” photosensitizers for use in PDT has developed due to the several photophysical restrictions of Photofrin II. Photofrin II is a poorly defined mixture of monomeric and aggregated porphyrins and has extremely weak absorption at wavelengths above 600 nm (where light transmission through tissue is greatest). In addition the drug is retained in numerous normal tissues (such as skin) for extended periods of time. Photosensitizers with preferential tumor tissue retention, rapid clearance from normal tissues, increased extinction coefficients and absorption peaks shifted to higher wavelengths, should allow for greater utilization of delivered light which has improved tissues transmission properties.