Nyman Emma S, Hynninen Paavo H
Laboratory of Organic Chemistry, Department of Chemistry, University of Helsinki, P.O. BOX 55 (A.I. Virtasen aukio 1), Helsinki FIN-00014, Finland.
J Photochem Photobiol B. 2004 Jan 23;73(1-2):1-28. doi: 10.1016/j.jphotobiol.2003.10.002.
Photodynamic therapy (PDT) is a promising new treatment modality for several diseases, most notably cancer. In PDT, light, O2, and a photosensitizing drug are combined to produce a selective therapeutic effect. Lately, there has been active research on new photosensitizer candidates, because the most commonly used porphyrin photosensitizers are far from ideal with respect to PDT. Finding a suitable photosensitizer is crucial in improving the efficacy of PDT. Recent synthetic activity has created such a great number of potential photosensitizers for PDT that it is difficult to decide which ones are suitable for which pathological conditions, such as various cancer species. To facilitate the choice of photosensitizer, this review presents a thorough survey of the photophysical and chemical properties of the developed tetrapyrrolic photosensitizers. Special attention is paid to the singlet-oxygen yield (PhiDelta) of each photosensitizer, because it is one of the most important photodynamic parameters in PDT. Also, in the survey, emphasis is placed on those photosensitizers that can easily be prepared by partial syntheses starting from the abundant natural precursors, protoheme and the chlorophylls. Such emphasis is justified by economical and environmental reasons. Several of the most promising photosensitizer candidates are chlorins or bacteriochlorins. Consequently, chlorophyll-related chlorins, whose PhiDelta have been determined, are discussed in detail as potential photosensitizers for PDT. Finally, PDT is briefly discussed as a treatment modality, including its clinical aspects, light sources, targeting of the photosensitizer, and opportunities.
光动力疗法（PDT）是一种对多种疾病，尤其是癌症很有前景的新型治疗方式。在光动力疗法中，光、氧气和一种光敏药物相结合以产生选择性治疗效果。最近，人们一直在积极研究新的光敏剂候选物，因为最常用的卟啉类光敏剂在光动力疗法方面远非理想。找到合适的光敏剂对于提高光动力疗法的疗效至关重要。近期的合成活动产生了大量用于光动力疗法的潜在光敏剂，以至于难以确定哪些适用于哪些病理状况，例如各种癌症类型。为便于选择光敏剂，本综述全面考察了已开发的四吡咯类光敏剂的光物理和化学性质。特别关注每种光敏剂的单线态氧产率（PhiDelta），因为它是光动力疗法中最重要的光动力参数之一。此外，在此次考察中，重点放在那些可以从丰富的天然前体原血红素和叶绿素开始通过部分合成轻松制备的光敏剂上。出于经济和环境原因，这种重点是合理的。一些最有前景的光敏剂候选物是二氢卟吩或细菌二氢卟吩。因此，已测定其PhiDelta的与叶绿素相关的二氢卟吩作为光动力疗法的潜在光敏剂将被详细讨论。最后，将简要讨论光动力疗法作为一种治疗方式，包括其临床方面、光源、光敏剂的靶向性以及机遇。
