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2 Materials Science

2 2002

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Spectroscopic studies on the inclusion complexes of etrakis(2-hydroxy-5-nitrophenyl)porphyrin with a-cyclodextrin in solution and in sol-gel matrix

Ribeiro A. O., Neri C. R., Iamamoto Y., Serra O. A.

Materials Science

2002

Vol. 20, No. 1

21-27

Tetrakis(2-hydroxy-5-nitrophenyl)porphyrin included in A-cyclodextrin (A-CD) photophysics was studied in aqueous media, in solid state and entrapped in a sol-gel matrix. The equilibrium constant of the pair porphyrin/A-CD was evaluated as 1.22x105 mol-1xdm-3. The nitroporphyrin was reduced to aminoporphyrin, included into the A-CD and then entrapped in the Si-O matrix network. The tetrakisporphyrin maintained its luminescent properties (with emission bands at 658 and 713 nm, excited at 422 nm) in all environments, indicating a structural stability under the experimental conditions.

Determination of the photodynamic activity of porphyrins: Potential photosensitizers for treatment of age-related macular degeneration

Neri C. R., Maestrin Prado A. P. J., Ribeiro A. O., Serra O. A., Iamamoto Y.

Materials Science

2002

Vol. 20, No. 2

97-103

Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in people between 65 and 74 years. Recently, the photodynamic therapy (PDT) is used as experimental treatment for exudative AMD. In a PDT process, a reaction takes place when a photosensitiser (PS), light of appropriated wavelength, and oxygen are present at the same time. In general, the PS are porphyrins and related systems. The aim of this study was to evaluate the photodynamic activity (PA) of the Benzoporphyrin (BPH2), Protophorphyrin-IX (Proto), Tetrakis(phydroxyphenyl) porphyrin (THPPH2) and Tetrakis(2-hydroxy-5-nitrophenyl)porphyrin (T2H5NPPH2). The PA is related to quantum yields (??) for the singlet oxygen (1O2.) production. Uric acid, a known singlet oxygen scavenger, is utilised as a chemical dosimeter in the PDT. When the uric acid (UA) and PS solution is irradiated with laser light the UA band absorbance at 293 nm decreases as a rapid evaluation of relative PA of the PS.