Physicochemical properties of potential porphyrin photosensitizers for photodynamic therapy

• Measurements of absorption and emission spectra of photosensitizers.
• Quantum yields of fluorescence and singlet oxygen generation by dyes.
• Determination of the triplet state lifetime using laser flash photolysis.
• Determination of fluorescence lifetimes using TCSPC method.
• Comparison of results with commercial compounds.

This research evaluated the suitability of synthetic photosensitizers for their use as potential photosensitizers in photodynamic therapy using steady state and time-resolved spectroscopic techniques. Four tetraphenylporphyrin derivatives were studied in ethanol and dimethyl sulfoxide. The spectroscopic properties namely electronic absorption and emission spectra, ability to generate singlet oxygen, lifetimes of the triplet state, as well as their fluorescence quantum yield were determined. Also time-correlated single photon counting method was used to precisely determine fluorescence lifetimes for all four compounds. Tested compounds exhibit high generation of singlet oxygen, low generation of fluorescence and they are chemical stable during irradiation. The studies show that the tested porphyrins satisfy the conditions of a potential drug in terms of physicochemical properties.

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