Baceriochlorophyll-serine Based Photochemotherapy; type III PDT?

Scherz, Avigdor; Katz, Sharon; Valcrat, Yahel; Brumfeld, Vlad; Gabelmann, Eva; Zilberstein, Judith; Leupold, D.; Norris, James R.; Scheer, Hugo; Salomon, Yoram

doi:10.1007/978-94-011-3953-3_974

Cited by 6 publications

(7 citation statements)

References 9 publications

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“…However, the poor solubility of the native compound in water limits its application to micellar or liposomic formulation. Furthermore, the hydrophobicity of the sensitizer may also slow down its clearance from normal tissue (3,4).…”

Section: Introductionmentioning

confidence: 99%

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

Eichwurzel

Stiel

Teuchner

et al. 2000

Photochem Photobiol

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We investigated the dependence on solvents of optical absorption and emission of the bacteriochlorophyll a-serine (BChl-ser), a water soluble bacteriochlorophyll (BChl) derivative. Comparison between the experimental data and those collected for BChl in nonaqueous solvents shows that only a minor interaction takes place between serine and the macrocycle's pi-electron system. Nevertheless, the coupling with serine results in a small enhancement of the nonradiative relaxation rate from the first excited singlet state S1. In buffered aqueous solution (pH = 7.4), the Stokes shift of the BChl-ser fluorescence and its nonradiative relaxation rate are enhanced compared with those in nonaqueous solutions (Scherz, A., S. Katz, Y. Vakrat, V. Brumfeld, E. Gabelmann, D. Leupold, J. R. Norris, H. Scheer and Y. Salomon (1998) Photosynthesis: Mechanisms and Effects, Vol. V (Edited by G. Garab), pp. 4207-4212. Kluwer Academic, Dordrecht.), probably as a result of a hydrogen bonding between the BChl macrocycle and the water molecules. In aprotic solvents, without hydrogen bonds, the permanent dipole moment of the first excited singlet state in both BChl and BChl-ser is increased compared with the ground state by at least 2.5 Debye.

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Section: Introductionmentioning

confidence: 99%

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

Eichwurzel

Stiel

Teuchner

et al. 2000

Photochem Photobiol

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“…The quantum efficiency for triplet state production is approximately 99%, with very high production of singlet oxygen, the putative toxic agent in PDT (type II mechanism). Further studies on the photochemistry of Tookad have revealed the highest photodynamic effect shortly after injection, 15 which seems to be due to ultrafast electron transfer from one Bchl to another in loosely coupled dimmers. The anion can reduce the oxygen presence, starting a chain of events ending with the ejection of the hydroxyl radical, an anion in a non-Fenton reaction.…”

mentioning

confidence: 99%

“…The anion can reduce the oxygen presence, starting a chain of events ending with the ejection of the hydroxyl radical, an anion in a non-Fenton reaction. 15 Because the radicals seem to be ejected directly from the excited sensitizer, it is suspected that their formation falls into neither a type I nor II process but represents a class by itself: a type III process. 15 Clinically, the main advantages of Tookad in comparison with other tested sensitizers are as follows: (1) Because of its high-wavelength absorbance, the exciting light beam is able to penetrate deeper into tissues and thus may permit an enhanced selective treatment of the choroidal vessels behind the strong absorbing RPE.…”

mentioning

confidence: 99%

Evaluation of the New Photosensitizer Tookad (WST09) for Photodynamic Vessel Occlusion of the Choroidal Tissue in Rabbits

Framme

Sachs

Flucke

et al. 2006

Invest. Ophthalmol. Vis. Sci.

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T-PDT has the potential to achieve selective choroidal vessel occlusion with proper parameter selection, such as (1) 2.5 mg/kg, 5 minutes, 100 J/cm2; (2) 5 mg/kg, 5 minutes, 25 J/cm2; or (3) 5 mg/kg, 15 minutes, 50 J/cm2; however, slight damage to the photoreceptors cannot be ruled out. RPE proliferation indicates primary RPE damage due to PDT, also described with the use of all other photosensitizers.

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“…Furthermore, the hydrophobicity of the sensitizer may also slow down its clearance from normal tissue (3,4).…”

Section: Introductionmentioning

confidence: 99%

“…Initial tests (3,4) have indeed shown that a 17 3 ester between bacteriochlorophyllide a and serine methyl ester (BChl-ser) is an improved PDT sensitizer compared with BChl, which calls for basic photophysical investigations of this new molecule.…”

Section: Introductionmentioning

confidence: 99%

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

Eichwurzel¹,

Stiel²,

Teuchner³

et al. 2007

Photochemistry and Photobiology

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Baceriochlorophyll-serine Based Photochemotherapy; type III PDT?

Cited by 6 publications

References 9 publications

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

Evaluation of the New Photosensitizer Tookad (WST09) for Photodynamic Vessel Occlusion of the Choroidal Tissue in Rabbits

Photophysical Consequences of Coupling Bacteriochlorophyll a with Serine and its Resulting Solubility in Water¶

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