Abstract
In recent years, drug-induced photosensitivity as a side effect has been an increasing problem. To examine the effectiveness of broad-spectrum sunscreens in preventing the disease, we quantitatively assessed efficiency of some sunscreens in suppressing the photosensitized reactions with sparfloxacin, a fluoroquinolone antibacterial agent. Some broad-spectrum sunscreens suppressed sparfloxacin-photosensitized formation of strand-breakage in plasmid pBR322 DNA. The present findings suggest that the use of broad-spectrum sunscreens contributes to the prevention of drug-induced photosensitivity. In addition, the suppressive effects showed a linear relation with the effective UV-A quanta absorbed by the tested sunscreens independent of the product types and manufacturers. Therefore, we propose that the indication of UV-A absorption spectrum in addition to PA classification (protection grade of UV-A) as factors for assessing for the ability of sunscreens to prevent drug-induced photosensitivity. An in vitro method to assess quantitatively the effectiveness of broad-spectrum sunscreens in preventing drug-induced photosensitivity was also presented.
