Park Seungwoo
Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
Korean J Gastroenterol. 2007 May;49(5):300-13.
Photodynamic therapy (PDT) has been used to treat several types of cancer, and comprises intravascular administration of photosensitizer, uptake by cancer cells, and followed by irradiation of light of appropriate wavelength. Although PDT takes advantage of relative retention of photosensitizer by cancer cells, effective delivery of photosensitizing drugs is of great concern. Several delivery strategies have been employed in PDT. Photosensitizers can be delivered either by passive carriers such as liposomes, micelles, and polymeric particles, or by active targeting using cancer cell-directed ligands or antibodies. Although well-studied colloidal carriers effectively deliver photosensitizer to tumor cells, they are taken up by mononuclear phagocytic system. Delivery system using polymers is an attractive alternative to colloidal carriers, in which hydrophobic drugs are chemically or physically loaded to polymers. Though there are several steps to be solved, targeted delivery system utilizing receptors or antigens abundantly expressed on cancer cell theoretically provides a great deal of advantages over passive system. Selective uptake of photosensitizers by cancer cells may greatly enhance therapeutic efficacy as well as minimizing adverse effects resulting from accumulation in normal tissue. This review discusses various strategies for photosensitizer delivery that have been investigated to date.
光动力疗法（PDT）已被用于治疗多种类型的癌症，其包括血管内给予光敏剂、癌细胞摄取光敏剂，随后照射适当波长的光。尽管光动力疗法利用了癌细胞对光敏剂的相对潴留，但光敏药物的有效递送备受关注。光动力疗法中已采用了多种递送策略。光敏剂可通过脂质体、胶束和聚合物颗粒等被动载体递送，也可通过使用癌细胞导向的配体或抗体进行主动靶向递送。尽管经过充分研究的胶体载体能有效地将光敏剂递送至肿瘤细胞，但它们会被单核吞噬系统摄取。使用聚合物的递送系统是胶体载体的一种有吸引力的替代方案，其中疏水性药物通过化学或物理方式负载到聚合物上。尽管有几个步骤有待解决，但理论上利用癌细胞上大量表达的受体或抗原的靶向递送系统比被动系统具有许多优势。癌细胞对光敏剂的选择性摄取可能会大大提高治疗效果，并将正常组织中积累所导致的不良反应降至最低。本综述讨论了迄今为止已研究的光敏剂递送的各种策略。
