Water-Soluble Chlorin/Arylaminoquinazoline Conjugate for Photodynamic and Targeted Therapy.

A new water-soluble conjugate, consisting of a chlorin- photosensitizer part, a 4-arylaminoquinazoline moiety with affinity to epidermal growth factor receptors, and a hydrophilic β-d-maltose fragment, was synthesized starting from methylpheophorbide- in seven steps. The prepared conjugate exhibited low levels of dark cytotoxicity and pronounced photoinduced cytotoxicity at submicromolar concentrations in vitro, with an IC(dark)/IC(light) ratio of ∼368 and a singlet oxygen quantum yield of about 20%. In tumor-bearing Balb/c nude mice, conjugate preferentially accumulates in the tumor tissue. Irradiation of the nude mice bearing A431 xenograft tumors after intravenous administration of the prepared conjugate with a relatively low light dose (50 J/cm) produced an excellent therapeutic effect with profound tumor regression and low systemic toxicity.