Photophysical studies of pheophorbide a and pheophytin a. Phosphorescence and photosensitized singlet oxygen luminescence

Krasnovsky, А.А.; Neverov, K.V.; Егоров, С. А.; Roeder, Beate; Levald, T.

doi:10.1016/1011-1344(90)80009-m

Cited by 102 publications

(62 citation statements)

References 7 publications

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“…At room temperature, pheophorbides are monomeric in organic solvents 9 and aggregated in polar solvents particular in aqueous solutions 41 . This properties is of importance due to its relation with the photodynamic activity of hydrophobic photosensitizers 39 .…”

Section: Aggregation Processmentioning

confidence: 99%

“…Among them, pheophorbide-a which presents selective accumulation in tumors, small toxicity and a photoxicity on tumor cells which can be 20-fold more efficient than hematoporphyrin derivatives 8 . The major advantages of pheophorbides are their absorption maximum around 660 nm and their monomeric state in organic solvents 9 . A series of effective photosensitizers derived from pheophorbide-a were synthesized since 1985.…”

Section: Introductionmentioning

confidence: 99%

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Physical and chemical properties of pyropheophorbide-a methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-l-α-phosphatidylcholine vesicles

Delanaye

Bahri

Tfibel

et al. 2006

Photochem Photobiol Sci

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This submission was created using the RSC Article Template (DO NOT DELETE THIS TEXT) (LINE INCLUDED FOR SPACING ONLY -DO NOT DELETE THIS TEXT)The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation photosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the photosensitizer was under a monomeric form in ethanol as well as in dimyristoyl-L-α-phosphatidylcholine liposomes while it was strongly aggregated in phosphate buffer. A quantitative determination of reactive oxygen species production by PPME in these solvents has been undertaken by electron spin resonance associated with spin trapping technique and absorption spectroscopy. In phosphate buffer, both electron spin resonance and absorption measurements led to the conclusion that singlet oxygen production was not detectable while hydroxyl radical production was very weak. In liposomes and ethanol, singlet oxygen and hydroxyl radical production increased highly; the singlet oxygen quantum yield was determined to be 0.2 in ethanol and 0.13 in liposomes. The hydroxyl radical production origin was also investigated. Singlet oxygen was formed from PPME triplet state deactivation in presence of oxygen. Indeed, the triplet state formation quantum yield of PPME was found to be about 0.23 in ethanol, 0.15 in liposomes (too small to be measured in PBS).

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Section: Aggregation Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physical and chemical properties of pyropheophorbide-a methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-l-α-phosphatidylcholine vesicles

Delanaye

Bahri

Tfibel

et al. 2006

Photochem Photobiol Sci

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“…This compound is a derivative bacteriological hydrochloric which produces high yield of the species being studied and is widely used as a reference in spectroscopic studies. 36 Therefore, these data suggest that BC does not interfere with the production of singlet oxygen, an important condition in the PDT process.…”

Section: Photophysical Characterizationmentioning

confidence: 91%

“…The experiments were done using a solution of pheophorbide A in ethanol as a standard for relative calculations. 36 The concentrations of reference solutions were adjusted based on the absorbance at 355 nm (excitation wavelength), fixed in 0.3 to avoid any internal filter effects. The measurements were performed under air-equilibrated conditions.…”

Section: Photophysical Studiesmentioning

confidence: 99%

Bacterial Cellulose Membranes as a Potential Drug Delivery System for Photodynamic Therapy of Skin Cancer

Peres¹,

Nigoghossian²,

Primo³

et al. 2016

Journal of the Brazilian Chemical Society

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The development of drug delivery systems for photodynamic therapy (PDT) is increasingly demanded due to the hydrophobicity presented by most of photosensitizers molecules. Bacterial cellulose (BC), a highly pure cellulose produced by bacteria, possesses the essential features for applications in drug delivery systems, such as large surface area and excellent loading capacity. BC membranes prepared containing a photosensitizer, chloroaluminum phthalocyanine (ClAlPc), were tested aiming applications as a drug delivery system for PDT skin cancer protocols. BC membranes production was optimized regarding thickness and optical transmission. Thinner membranes lead to higher relative incorporation efficiencies. Skin permeation and retention in vitro tests were performed by using pig's ears as a skin model. ClAlPc was retained at stratum corneum and epidermis/dermis, showing adequate properties for topical administration of ClAlPc. Photophysical studies showed that singlet oxygen production was not affected for ClAlPc compartmentalized in the BC array. BC-ClAlPc membranes did not present cytotoxic effects in vitro.

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“…Association is favored for amphiphilic molecules with polar or charged chains located only on one side of the macrocycle (Dairou et al 2002). The Xuorescence and most frequently the singlet oxygen quantum yields of aggregated species are lower than those of monomeric form, reducing their photodynamic eYcacy (Krasnovsky Jr et al 1990), although this rule is not unequivocal (Dairou et al 2002;Moan 1984). The formation of large-scale aggregates upon injection of quite hydrophobic PS may considerably modify their pharmacokinetics as compared to monomer forms.…”

Section: Aggregation Statementioning

confidence: 93%

ROS: Reactive Oxygen Species

김윤미¹,

김영찬²,

정신교³

2013

Encyclopedia of Metalloproteins

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New therapies have been developed using reactive oxygen species produced by light-activation of photosensitizers (PS). Since the lifetime of these species is extremely short and their diVusion in space is limited, the photo-induced reactions primarily aVect the cell organelles labeled by the PS. In addition to the development of molecules with the best optical and photosensitizing properties, considerable research has been done to understand the physico-chemical parameters governing their subcellular localization. In this review, we examine these parameters to establish the structure/eYcacy relationships, which allow speciWc targeting of PS. We examine the eVect of subcellular localization on the cellular response to photosensitization processes. We discuss the determinants of subcellular localization, including the hydrophobic/hydrophilic balance, the speciWc charge eVects and the dynamics of PS' transfer through membranes. SpeciWc targeting can also be achieved with molecular structures able to recognize cellular or intracellular receptors, and this is also dealt with in this paper.

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Photophysical studies of pheophorbide a and pheophytin a. Phosphorescence and photosensitized singlet oxygen luminescence

Cited by 102 publications

References 7 publications

Physical and chemical properties of pyropheophorbide-a methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-l-α-phosphatidylcholine vesicles

Physical and chemical properties of pyropheophorbide-a methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-l-α-phosphatidylcholine vesicles

Bacterial Cellulose Membranes as a Potential Drug Delivery System for Photodynamic Therapy of Skin Cancer

ROS: Reactive Oxygen Species

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