| 1. |
- Bendsoe, Niels, et al.
(författare)
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Fluorescence monitoring of a topically applied liposomal temoporfin formulation and photodynamic therapy of nonpigmented skin malignancies.
- 2007
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Ingår i: Journal of Environmental Pathology and Toxicology. - 2162-6537. ; 26:2, s. 117-126
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Tidskriftsartikel (refereegranskat)abstract
- Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (INN: Temoporfin) is a potent photodynamically active substance in clinical use today. Usually, the substance is given systemically and a known drawback with this administration route is a prolonged skin light sensitization. For the first time to our knowledge, a liposomal Temoporfin gel formulation for topical application was studied in connection with photodynamic therapy (PDT) of nonpigmented skin malignancies in humans. Intervals of 4 hr between drug administration and light irradiation were used. Sensitizer distribution within tumor and surrounding normal skin was investigated by means of point monitoring and imaging fluorescence spectroscopy before, during, and after PDT, showing high tumor selectivity. Furthermore, the bleaching of Temoporfin was studied during the PDT procedure by monitoring the fluorescence following excitation by using a therapeutic light. A 30−35% light-induced photometabolization was shown. No pain occurred during or after treatment. It was also observed that the treated area did not show any swollen tissue or reddening, as is often seen in PDT using topical δ-aminolevulinic acid. On controlling the patients one week after treatment, healing progress was observed in several patients and no complications were registered.
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| 2. |
- Johansson, Ann, et al.
(författare)
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Fluorescence and absorption assessment of a lipid mTHPC formulation following topical application in a non-melanotic skin tumor model.
- 2007
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668. ; 12:3, s. 034026-034026
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Tidskriftsartikel (refereegranskat)abstract
- Although the benefits of topical sensitizer administration have been confirmed for photodynamic therapy (PDT) ALA-induced, protoporphyrin IX is the only sensitizer clinically used with this administration route. Unfortunately, ALA-PDT results in poor treatment response for thicker lesions. Here, selectivity and depth distribution of the highly potent sensitizer meso-tetra(hydroxyphenyl)chlorin (mTHPC), supplied in a novel liposome formulation was investigated following topical administration for 4 and 6 h in a murine skin tumor model. Extraction data indicated an average [standard deviation (SD)] mTHPC concentration within lesions of 6.0(+/- 3.1) ng/mg tissue with no significant difference (p<0.05) between 4- and 6-h application times and undetectable levels of generalized photosensitivity. Absorption spectroscopy and chemical extraction both indicated a significant selectivity between lesion and normal surrounding skin at 4 and 6 h, whereas the more sensitive fluorescence imaging setup revealed significant selectivity only for the 4-h application time. Absorption data showed a significant correlation with extraction, whereas the results from the fluorescence imaging setup did not correlate with the other methods. Our results indicate that this sensitizer formulation and administration path could be interesting for topical mTHPC-PDT, decreasing the effects of extended skin photosensitivity associated with systemic mTHPC administration. (C) 2007 Society of Photo-Optical instrumentation Engineers.
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| 3. |
- Johansson, Ann, et al.
(författare)
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mTHPC pharmacokinetics following topical administration
- 2006
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Ingår i: Optical Diagnostics and Sensing VI. - : SPIE. - 1996-756X .- 0277-786X. ; 6094, s. 940-940
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Konferensbidrag (refereegranskat)abstract
- Measurements of concentration of sensitizers for photodynamic therapy can provide important information in the dosimetry planning and can also give input to the optimal time for treatment. There has been skepticism towards fluorescence techniques for this purpose, as the signal depends on the fluorescence yield and optical properties of the tissue. Absorption based techniques, lack on the other hand, often the sensitivity required for many sensitizers with relative weak absorption in a wavelength region where hemoglobin absorption is dominant. A direct comparison between absorption and fluorescence techniques for measuring mTHPC concentration after topical application on hairless SKH-1 mice bearing skin carcinomas has been performed. 20 μl/cm2 of m-THPC thermogel (0.5 mg m-THPC/ml) were applied on normal and tumor area and the concentration of mTHPC was measured at 4 and 6 hours after drug application by two methods: 1. A fluorescence imaging system capturing images at two wavelengths (500 and 650 nm) following 405 nm excitation. Signals from different regions of interest were averaged and the intensity ratio at 650 to 500 was calculated. 2. A diffuse reflectance spectroscopy system with a fiber separation of 2 mm, providing the absorbance at 652 nm. Both systems provided consistent results related to the photosensitizer concentration. The methods show a remarkable difference in the concentration of photosensitizer in normal skin and tumor. No significant difference in mTHPC concentration in tumor could be observed between the 4 and 6h groups after drug application.
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| 4. |
- Svensson, Jenny, et al.
(författare)
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Pharmacokinetic study of a systemically administered novel liposomal Temoporfin formulation in an animal tumor model
- 2007
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422 .- 1042-4687. ; 6427, s. 4270-4270
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Konferensbidrag (refereegranskat)abstract
- Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (international generic name Temoporfin) is a potent photosensitizer used for photodynamic therapy (PDT). In this study the pharmacokinetics of a systemically administered novel lipid formulation of Temoporfin in a murine tumor model has been investigated. Fluorescence spectroscopy measurements were performed at several time intervals following drug administration, yielding information on the Temoporfin concentration within excised internal organs as a function of time after injection. Both point-monitoring and imaging setups were used. The acquired fluorescence data were correlated to the concentration of Temoporfin obtained with High Performance Liquid Chromatography (HPLC). There was a significant correlation between the fluorescence methods and HPLC for most organs investigated. The pharmacokinetics of this new liposomal formulation of Temoporfin exhibited a rather flat temporal profile in the time interval 2-8 hours in this study.
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