Toxicological studies on a new macrolide antibiotic, midecamycin acetate (miokamycin). Part III-1. Chronic toxicity in rats.

Miokamycin (MOM) is a derivative of midecamycin, a macrolide antibiotic isolated from a culture broth of Streptomyces mycarofaciens. The objective of this study was to determine the chronic toxicity of MOM in male and female rats (Wistar, SPF, 5-week-old) after repeated oral administration of MOM, non-crystalline solid, for 26 weeks at daily dosages of 62.5, 125, 250, 500 and 1,000 mg/kg. The lowest dosage level of 62.5 mg/kg/day was only applied for female rats. In conclusion, the maximum non-toxic dosage level of MOM, non-crystalline solid, is presumed to be 250 mg/kg in male and female rats with p.o. administered once daily for 26 weeks.