The present invention provides pharmaceutical photosensitizer-loaded nanoparticle formulations and their methods of preparation for photodynamic therapy, comprising a hydrophobic or hydrophilic photosensitizer, nanoparticulate calcium phosphate and in certain cases auxiliary reagents such as stabilizers. The calcium phosphate-based nanoparticle formulations of the present invention provide excellent storage stability and therapeutically effective amounts of photosensitizer for intravenous or topical administration. In a preferred embodiment, tetrapyrrole derivatives such as porphyrins, chlorins and bacteriochlorins, are the preferred hydrophobic photosensitizers to be formulated in calcium phosphate nanoparticle formulations for photodynamic tumor therapy. Additionally, 5,10,15,20-tetrakis(4-phosphonooxyphenyl)porphine (pTPPP) is a preferred hydrophilic photosensitizer for photodynamic tumor therapy. In another preferred embodiment, hydrophilic cationic and anionic photosensitizers, especially those of the phenazinium, phenothiazinium and xanthenes series have been found to inactive pathogen bacteria and are the preferred photosensitizers to be formulated in calcium phosphate nanoparticle formulations for antibacterial photodynamic therapy. In another embodiment, photosensitizing nanoparticle formulations are useful to locate cells, tissues or bacteria by using fluorescence imaging methods.
