Photodynamic therapy with chlorin-based photosensitizer at 405 nm: numerical, morphological, and clinical study

Abstract

Employment of chlorin-based photosensitizers (PSs) provides additional advantages to photodynamic therapy (PDT) due to absorption peak around 405 nm allowing for superficial impact and efficient antimicrobial therapy. We report on the morphological and clinical study of the efficiency of PDT at 405 nm employing chlorin-based PS. Numerical studies demonstrated difference in the distribution of absorbed dose at 405 nm in comparison with traditionally employed wavelength of 660 nm and difference in the in-depth absorbed dose distribution for skin and mucous tissues. Morphological study was performed at the inner surface of rabbit ear with histological examinations at different periods after PDT procedure. Animal study revealed tissue reaction to PDT consisting in edema manifested most in 3 days after the procedure and neoangiogenesis. OCT diagnostics was confirmed by histological examination. Clinical study included antimicrobial PDT of pharynx chronic inflammatory diseases. It revealed no side effects or complications of the PDT procedure. Pharyngoscopy indicated reduction of inflammatory manifestations, and, in particular cases, hypervascularization was observed. Morphological changes were also detected in the course of monitoring, which are in agreement with pharyngoscopy results. Microbiologic study after PDT revealed no pathogenic bacteria; however, in particular cases, saprophytic flora was detected.

Dual-Wavelength Fluorescence Monitoring of Photodynamic Therapy: From Analytical Models to Clinical Studies

“…The layer thickness varied between 0.34 and 3 mm. In a PS-containing layer, a water-based PS gel Revixan Derma (Revixan Ltd., Moscow, Russia) containing 0.1% pure chlorin e6 [ 30 ] was added to the base phantom in a liquid state to ensure a PS concentration of C 0 = 0.1% vol.…”

“…For the intravenous injection, a NaCl solution of Fotolon (Belmedpreparaty, Minsk, Belarus) [ 35 , 36 , 37 , 38 ] or an injection form of Fotoditazin (Veta-Grand Ltd., Moscow, Russia) [ 35 , 39 ] was used. For the topical administration, a gel form of Revixan Derma (Revixan Ltd., Moscow, Russia) [ 30 ] or Fotoditazin (Veta-Grand Ltd., Moscow, Russia) [ 35 , 39 ] was employed. Despite the differences in the particular formulations, all of these drugs are equivalent from the point of view of dual-wavelength imaging featuring the fluorescence spectral properties depicted in Figure 1 .…”

Comparative analysis of single- and dual-wavelength photodynamic therapy regimes with chlorin-based photosensitizers: animal study

“…in turbid media followed by the statistical analysis of the collected data. A custom-developed MATLAB-based implementation 24,33 of Monte Carlo algorithm was employed to simulate the distribution of absorbed light dose in a rabbit ear for irradiation at 405 and 660 nm. Simulations were performed for a planar three-layered model of a rabbit ear with the thickness of 1 mm, where top and bottom layers correspond to the skin tissues and the intermediate layer corresponds to the cartilage.…”

“…Moreover, blue light was demonstrated to stimulate neoangiogenesis at low doses, which is important for regenerative medicine. 24 In particular cases, drug treatment strategy against inflammatory diseases strongly depends on the proper selection of a drug that is efficient against a particular causative agent. When the causative agent is not determined, the drug treatment may show weak efficacy, while PDT acts as a wide-range aid and can serve a method of choice in this situation.…”

“…[8][9][10][11][12] There are several reports on the application of blue spectral range with such PSs as aminolevulinic acid or methyl aminolevulinate, 6,20,25,26 which also have several absorption peaks including red and blue bands; however, the reported applications with chlorin-based PS are very limited. 14,24 In our previous paper, 24 we reported on a clinical study of antimicrobial PDT of pharynx chronic inflammatory diseases with topical application of chlorin-based PS and irradiation wavelength of 405 nm. The employed PDT protocol revealed no side effects or complications, while microbiological study after PDT revealed no pathogenic bacteria.…”