[Single dose toxicity studies of suplatast tosilate (IPD-1151T)]

Single dose toxicity studies of suplatast tosilate (IPD-1151T) were carried out in mice, rats and dogs of both sexes. The results were as follows: 1. The LD50 values of IPD-1151T were as follows: Mice, 12,500 (both sexes) mg/kg or more in oral route (maximum dose for technical manner); Mice 81 (male) and 96 (female) mg/kg in intravenous route; Rats, 10,000 (both sexes) mg/kg or more in oral route (maximum dose for technical manner); Rats, 96 (male) and 93 (female) mg/kg in intravenous route; Dogs, 2,124 (male) and 2,660 (female) mg/kg in oral route. On the LD50 values, no sexual difference was apparent in all species, but the species difference was noted between the rodent and dog. LD50 values of dog were lower level than those of rodent. 2. As toxic signs, mucous diarrhea with specific smell was noted in orally administered rodent. In addition, rats showed soiled fur in the perianal. In intravenous route, the rodent showed dyspnea, tonic convulsion and lateral position and deaths occurred within 10 min in mice and within 30 min in rats after administration. Dog showed toxic signs similar to those in rodents and deaths occurred within 3 hours. 3. In pathological examinations, dead mice and dogs administered orally showed lung congestion, liver fading or slight hemorrhage in the endo-and/or exocardium. Dead rodent administered intravenously showed only slight hemorrhage and congestion in the lung. Alive mice, rats and dogs showed no remarkable changes. 4. The main cause of deaths seemed to be respiratory disturbance in all species.