Studies on experimental conditions for detecting phototoxic potentials of drugs in Balb/c mice.
This study was designed to establish a procedure for detecting the phototoxicity of drugs in an animal model. Experimental conditions in relation to intensity distribution of ultraviolet-A (UVA), duration of irradiation, and suitable region for irradiation were investigated. One black light gave a wide constant-energy region when the distance from the light source to the irradiation area was 15 cm. The intensity distribution of a bank of 10 black lights formed a pattern like the contour map of a truncated cone in the irradiation area. In phototoxic studies, Balb/c strain mice were orally administered chlorpromazine and nalidixic acid, clinically known as photosensitizers, and were immediately exposed to UVA irradiation. The optimal irradiation time was 4 hours at an energy of 20 Joules/cm2, which with a high frequency caused erythema on the surface of the ears in the central area, which received about 1.5 mW/sec.cm2, but no reaction occurred in the surrounding area (0.5-0.8 mW/sec.cm2). These results indicate that it is important to select a suitable irradiation area and sufficient intensity of irradiation in order to determine whether a drug has phototoxic potential.
Wagai
N
N
Research Institute, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan.
Yamaguchi
F
F
Tawara
K
K
Onodera
T
T
D000818:Animals; D002746:Chlorpromazine / Q000633:toxicity*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009268:Nalidixic Acid / Q000633:toxicity*; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D014466:Ultraviolet Rays
D009268:Nalidixic Acid; D002746:Chlorpromazine