Hypocrellins as photosensitizers for photodynamic therapy : a screening evaluation and pharmacokinetic study

Hypocrellin compounds were selected as potential photosensitizers for photodynamic therapy (PDT) owing to their high quantum yields of singlet oxygen (1O2), and facility for site-directed chemical modification to enhance phototoxicity, pharmacokinetics, solubility, and light absorption in the red sp...

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Bibliographic Details
Published in:Cancer chemotherapy and pharmacology 1996, Vol.37 (4), p.343-350
Main Authors: ESTEY, E. P, BROWN, K, DIWU, Z, LIU, J, LOWN, J. W, MILLER, G. G, MOORE, R. B, TULIP, J, MCPHEE, M. S
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Medical sciences
Mice
Perylene - analogs & derivatives
Perylene - pharmacokinetics
Perylene - pharmacology
Photochemotherapy - methods
Photoradiation therapy and photosensitizing agent
Photosensitizing Agents - pharmacokinetics
Photosensitizing Agents - pharmacology
Quinones - pharmacokinetics
Quinones - pharmacology
Treatment with physical agents
Treatment. General aspects
Tumor Cells, Cultured
Tumors
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Summary:Hypocrellin compounds were selected as potential photosensitizers for photodynamic therapy (PDT) owing to their high quantum yields of singlet oxygen (1O2), and facility for site-directed chemical modification to enhance phototoxicity, pharmacokinetics, solubility, and light absorption in the red spectral region, among other properties. Parent hypocrellins A and B share an absorption peak at 658 nm. These molecules may therefore be considered useful progenitors of derivatives which absorb more strongly in the red, considering that the ideal sensitizer should absorb in the 650-800 nm range, beyond the absorption range of hemoglobin and melanin, and where light penetration in tissues is maximized through reduced scattering. A series of pure, monomeric hypocrellin derivatives was tested for properties of dark cytotoxicity and photosensitizing potential by clonogenic assay in monolayer cultures of EMT6/Ed murine tumor cells. Their respective toxicities are reported on a molar basis. The in vitro screening assay has, to date, resulted in the selection of four hypocrellin derivatives for further development as photosensitizers for PDT. Cellular uptake for photosensitizing doses of selected compounds was determined by fluorimetry. Dose escalation studies in rodents indicate that potentially photosensitizing doses promote no demonstrable systemic toxicity.
ISSN:0344-5704
1432-0843
DOI:10.1007/s002800050395