Peptide-targeted dendrimeric prodrugs of 5-aminolevulinic acid: A novel approach towards enhanced accumulation of protoporphyrin IX for photodynamic therapy

K. M. Tewari, R. Dondi, E. Yaghini, C. Pourzand, A. J. MacRobert, I. M. Eggleston

Research output: Contribution to journalArticlepeer-review


Photodynamic therapy (PDT) is a promising approach for the targeted treatment of cancer and various other human disorders. An effective, clinically approved approach in PDT involves the administration of 5-aminolevulinic acid (ALA) to generate elevated levels of the natural photosensitiser protoporphyrin IX (PpIX). The development of prodrugs of ALA is of considerable interest as a means to enhance the efficiency and cell selectivity of PpIX accumulation for PDT applications. In this work a novel peptide-targeted dendrimeric prodrug of 5-aminolevulinic acid (ALA) 13 was synthesised which displays nine copies of ALA on a core structure that is linked to a homing peptide for targeted delivery to a specific cancer cell type. The synthesis was accomplished effectively via a flexible, modular solid phase and solution phase route, using a combination of solid phase peptide synthesis and copper-catalysed azide-alkyne cycloaddition chemistry. The prodrug system shows a sustained and enhanced production of protoporphyrin IX (PpIX) in the MDA-MB-231 cell line that over-expresses the epidernal growth factor receptor (EGFR+) in comparison to equimolar ALA and the corresponding non-targeted ALA dendrimer (nine copies of ALA). This study provides a proof of concept for the development of a new generation of prodrugs for ALA-based photodynamic therapy that can deliver an enhanced ALA payload to specific tissue types.

Original languageEnglish
Article number104667
JournalBioorganic Chemistry
Early online date28 Jan 2021
Publication statusE-pub ahead of print - 28 Jan 2021


  • Aminolevulinic acid
  • Click chemistry
  • Fluorescence diagnosis
  • Peptide
  • Photodynamic therapy
  • Prodrug
  • protoporphyrin IX

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Drug Discovery
  • Organic Chemistry

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