Optical properties of cytostatic drugs used in cancer treatment

摘要

A spectroscopical characterization of methotrexate, cytostatic drag used frequently in cancer therapy, was performed. The absorption, emission and excitation spectra were measured for methotrexate solutions in natural saline and sodium hydroxide at concentration in the range 10~(-5) M -10~(-6) M and pH 8.4. The absorption bands are noticed in the spectral range 2SO nm - 450 nm. The fluorescence excitation was made at 340 nm and 370 nm; the fluorescence emission was detected in the spectral range 400 nm - 500 nm with a maximum at 450 nm. The behaviour of absorption and fluorescence spectra of methotrexate solution exposed to uv - visible light was investigated. The irradiation was made using a Xe lamp (emission bwtween 325 nm and 420 nm and power density of 11 mW/cm~2 ). The exposure time was between 15 min. and 3 h. Major modifications on absorption bands for irradiation times longer than 1 hour were observed. Furthermore, the methotrexate solutions become strongly fluorescent after irradiation. The observed changes are not linear with the exposure time indicating complex photochemical processes which implies, at least, one intermediate product.