Abstract The physiological substance and precursor of the heme synthesis 5-aminolevulinic acid (ALA) is a promising prodrug for photodiagnosis and photodynamic therapy of epithelial tumors, particularly in urological and gynecological tissues. For the clinical use of this substance, a chemically stable and sterile drug formulation is required. In the present study, degradation mechanism of ALA in aqueous solution and possibilities to improve its ...
