Melanoma is the most malignant skin tumor caused by the malignancy of melanocytes that produce the melanin pigment. Various methods have been developed to combat melanoma, with photodynamic therapy (PDT) gaining the spotlight for its ability to eliminate cancer cells by generating reactive oxygen species through light-sensitive photosensitizers. 5-aminolevulinic acid (5-ALA) is the most commonly used PDT agent, which could be converted to the PpIX photosensitizer molecule within cancer cells. However, its high hydrophilicity limits effective transdermal and oral delivery. In this work, we present a novel polymer formulation, named 5-AP, designed for the transdermal delivery of 5-ALA to deep melanoma tumor sites. 5-AP was prepared by the