6 March 2006 Distribution studies of m-THPC after topical application of m-THPC thermogel in a murine non-melanoma skin cancer tumor model by fluorescence spectroscopic and imaging techniques
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Abstract
m-THPC photodynamic therapy has been successfully studied in skin cancer, but no research effort concerning its topical application has been performed until now. Determination of the biodistribution of a special m-THPC thermogel formulation and its tumour selectivity was studied after topical application on hairless SKH-1 mice bearing non-melanoma skin carcinomas. 20 μl/cm2 of m-THPC thermogel (0.5 mg m-THPC/ml) were applied on normal and tumour area and the concentration or demarcation of tumor by mTHPC fluorescence was measured at 2, 4 and 6 hours after drug application by three methods: 1. A fluorescence imaging system capturing images at two emission wavelengths (500 and 654 nm) following 405 nm excitation. Signals from different regions of interest were averaged and the intensity ratio at 654 to 500 was calculated. 2. A fluorescence spectrometer with a fiber bundle for in vivo spectra recording after 420 nm excitation. 3 Each animal was euthanized and the photosensitizer was chemically extracted from liver, spleen, muscle, normal skin and tumour. The photosensitizer concentrations in the extracts and in plasma were determined by fluorescence spectroscopy. The in vivo methods showed a remarkable difference in the concentration of photosensitizer in normal skin and tumour. The highest concentration in tumour was observed 6h after drug application and the highest fluorescence intensity ratio of m-THPC in tumour to normal tissue was observed at 4 hours. Furthermore, no m-THPC was detected in normal tissues or plasma after drug topical application. In vivo and ex vivo results were consistent.
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Eleni Alexandratou, Maria Kyriazi, Dido Yova, Susanna Gräfe, Tilmann Trebst, Ann Johansson, Katarina Svanberg, Niels Bendsoe, Stefan Anderson-Engels, "Distribution studies of m-THPC after topical application of m-THPC thermogel in a murine non-melanoma skin cancer tumor model by fluorescence spectroscopic and imaging techniques", Proc. SPIE 6139, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV, 61390G (6 March 2006); doi: 10.1117/12.646142; https://doi.org/10.1117/12.646142
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KEYWORDS
Luminescence

Fluorescence spectroscopy

Skin cancer

Spectroscopy

Tumor growth modeling

Tumors

Imaging spectroscopy

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