title: On the photodynamic therapy action spectrum of zinc phthalocyanine tetrasulphonic acid in vivo.
abstract: The photodynamic therapy (PDT) activity of zinc phthalocyanine tetrasulphonic acid in a rodent tumour model was shown to be critically dependent on the wavelength of the excitation laser light over a relatively small wavelength range. Thus the sensitizer showed a doubling of the PDT activity with fibrosarcoma LSBD1 in BDIX rats when the wavelength of the illuminant was displaced from 680 to 692 nm. Under these conditions, the sensitizer is approximately three times more effective than polyhaematoporphyrin, whereas previously it has been considered to be of low PDT activity. This wavelength effect is attributed to a red shift of the absorption spectrum of the sensitizer in cells compared with that in solution. Fluorescence excitation studies with sensitizer absorbed in mouse 3T3 fibroblast cells are consistent with such a red shift.
authors.affiliation: Centre for Photomedicine and Photobiology, University of Leeds, UK.
authors.forename: J
authors.initials: J
authors.lastname: Griffiths
authors.forename: J
authors.initials: J
authors.lastname: Cruse-Sawyer
authors.forename: S R
authors.initials: SR
authors.lastname: Wood
authors.forename: J
authors.initials: J
authors.lastname: Schofield
authors.forename: S B
authors.initials: SB
authors.lastname: Brown
authors.forename: B
authors.initials: B
authors.lastname: Dixon
mesh_terms: D000818:Animals; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy*; D007211:Indoles / Q000627:therapeutic use*; D008027:Light; D009942:Organometallic Compounds / Q000627:therapeutic use*; D010778:Photochemotherapy; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*; D051381:Rats; D011919:Rats, Inbred Strains; D012513:Sarcoma, Experimental / Q000188:drug therapy
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D011838:Radiation-Sensitizing Agents; C052735:zinc tetrasulfophthalocyanine