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In vitro evaluation of Radachlorin® sensitizer for photodynamic therapy

Paper ID Volume ID Publish Year Pages File Format Full-Text
31086 44539 2010 10 PDF Available
Title
In vitro evaluation of Radachlorin® sensitizer for photodynamic therapy
Abstract

This paper reports the evaluation of a new photosensitizer, Radachlorin® in comparison with one of its well known components but used solely, Chlorin e6. The photodynamic properties and cell uptake and localisation of the two drugs were compared. In vitro studies were conducted on human adenocarcinoma cells (HT29) and lung carcinoma cell line (A549). Both dyes showed an absorption maximum between 640 and 650 nm, but those absorption peaks are enhanced by interactions with serum, with a shifted maximum at 661 and 664 nm, and much higher absorbance. As Radachlorin® is constituted of different products and as photoreactivity is dependent on absorbed light energy, we chose to adapt concentrations so that both drugs had the same absorption at the irradiation wavelength (664 nm) for photoreactivity tests, and express concentrations in optical density at 664 nm. The capacity of the two drugs to generate Reactive Oxygen Species was identical, but on HT29 cells, Radachlorin® reaches its optimal LD50 sooner than Chlorin e6. Radachlorin® LD50 on HT29 cells was 0.0251 OD664nm after 2 h and 0.0672 OD664nm for Chlorin e6 for a 20 J cm−2 irradiation. Radachlorin® gave very similar results on A549 cells, LD50 being 0.05 for 5 J irradiation, and 0.026 for 10 and 20 J cm−2. Pharmacokinetics using fluorescence showed that, even if Radachlorin® quickly crossed HT29 (a human colonic cancer line) cell membrane, cellular distribution evolved from a diffuse cytoplasmic repartition 1 hour after Radachlorin® addition to a delimited localisation into organelles all around the nucleus. Radachlorin® intracellular fluorescence decreased after 4 h, whereas we did not observe a decrease of Chlorin e6 intracellular fluorescence for times up to 24 h. In both case, a quick decline was observed as soon as the culture medium was replaced with a drug-free one. Radachlorin® appears to be an excellent photosensitizer, with similar phototoxicity to Chlorin e6 on cell cultures, but with quicker kinetics, which could be an improvement if confirmed on further in vivo studies.

Keywords
Photodynamic therapy; Phototoxicity; Radachlorin®; Chlorin e6; Cancer; HT29
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In vitro evaluation of Radachlorin® sensitizer for photodynamic therapy
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 98, Issue 2, 12 February 2010, Pages 128–137
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us