Enhanced Photodynamic Therapy Efficacy through Solid Lipid Nanoparticle of Purpurin-18-N-Propylimide Methyl Ester for Cancer Treatment

Photodynamic therapy (PDT) is an innovative cancer treatment that utilizes light. When light irradiates, purpurin-18-N-propylimide methyl ester (P18 N PI ME) generates reactive oxygen species that destroy cancer cells. The hydrophobic nature of P18 N PI ME presents challenges regarding its aggregation in the body, which can affect its effectiveness. This study aimed to enhance the bioavailability and effectiveness of cancer treatment by synthesizing P18 N PI ME and formulating P18 N PI ME-loaded solid lipid nanoparticles (SLNs). The efficacy of PDT was estimated using the 1,3-diphenylisobenzofuran (DPBF) assay and photocytotoxicity tests on the HeLa (human cervical carcinoma) and A549 (human lung carcinoma) cell lines. The P18 N PI ME-loaded SLNs demonstrated particle sizes in the range of 158.59 nm to 248.43 nm and zeta potentials in the range of -15.97 mV to -28.73 mV. These SLNs exhibited sustained release of P18 N PI ME. DPBF analysis revealed enhanced PDT effects with SLNs containing P18 N PI ME compared with standalone P18 N PI MEs. Photocytotoxicity assays indicated toxicity under light irradiation but no toxicity in the dark. Furthermore, the smallest-sized formulation exhibited the most effective photodynamic activity. These findings indicate the potential of P18 N PI ME-loaded SLNs as promising strategies for PDT in cancer therapy.