The systemic or local administration of a photosensitizer for photodynamic therapy is highly limited by poor selectivity, rapid deactivation and long-lasting skin toxicity due to unfavorable biodistribution. Drug delivery systems based on nanocarriers may help specific and effective delivery of photosensitizers. In the present paper, the interaction of two photosensitizers, methylene blue and rose bengal, with phosphorous cationic and anionic dendrimers as potential nanocarriers, has been characterized. A novel method is presented based on the analysis of the infrared spectra of mixtures of photosensitizer and dendrimer. The capacity of dendrimers to bind the photosensitizers has been evaluated by obtaining the corresponding binding curves. It is shown that methylene blue interacts with both cationic and anionic dendrimers, whereas rose bengal only binds to the cationic ones. Dendrimers are shown to be potential nanocarriers for a specific delivery of both photosensitizers.
Keywords: Dendrimer-photosensitizer interactions; Infrared spectroscopy; Methylene blue; Phosphorus dendrimer; Rose bengal.