Spectral and photobleaching properties of hematoporphyrin monomethyl ether

Abstract

The absorption spectrum, fluorescence excitation and emission spectrum of new photosensitive drug Hematoporphyrin Monomethyl Ether (HMME) in physiological saline with 10 percent human serum were obtained. Experimental results show that the maximum absorption peaks for HMME in physiological saline with 10 percent serum appear at 400nm in the soret region. There are two major peaks, at 620nm and at 685nm in fluorescence emission spectrum of HMME when excited by light with the wavelength of 41 3. mm. Furthermore, the photobleaching properties of HMME in tissue phantom irradiated by J( laser were determined from the intensity fluctuations of the collected fluorescence. The photobleaching time of HMME increased with the increasing of HMME concentration, while the photobleaching time of HMME decreased with the increasing of irradiated laser power. When the power of irradiation and the concentration of HMME equal to 12mW and 3ig/ml, respectively, the photobleaching time of HMME is approximately 190 second. All of these results provide the implications for the clinical application and dosimetry of HMJ\4E in the photodynamic diagnosis of cancers.