131I-5-IPN

**131I-5-IPN** is a radioiodinated small molecule designed for *targeted radionuclide therapy (TRNT)* of pigmented malignant melanoma[2][3][1]. It is a melanin-targeting agent, based on a picolinamide scaffold, labeled with iodine-131. The drug exhibits high melanin binding affinity and specificity, leading to selective uptake and retention in melanin-rich tumor tissues[2][1]. Mechanistically, 131I-5-IPN binds to melanin and delivers cytotoxic beta radiation via the 131-iodine isotope, causing localized DNA damage and cell death in melanoma cells. Preclinical studies in murine models show that TRNT with 131I-5-IPN significantly inhibits tumor growth and extends survival without causing significant toxicity to non-target organs[2][3]. Investigations also note its utility as a theranostic agent for imaging and therapy, and combination with immune checkpoint inhibitors such as anti-PD-L1 further enhances antitumor effects[1].

Other names

131I-N-(2-(diethylamino)ethyl)-5-(iodo-131I)picolinamide