Reduced pulmonary toxicity of peplomycin in a new drug-delivery system.

Pulmonary toxicity was examined by means of Matsuda and Takahashi's procedure in peplomycin solution, and two types of a new dosage form of peplomycin (PEP-CH), which has peplomycin adsorbed on to activated carbon particles. One was PEP-CH IP, and is designed for intraperitoneal administration. The other was PEP-CH IM, for intramuscular administration. Male mice of ICR strain received a bolus injection of 50 mg kg-1 peplomycin in the form of aqueous solutions PEP-CH IP and PEP-CH IM. The survival rate was 100% after 5 weeks in both groups that were administered PEP-CH. The rate was 50% for the group given peplomycin solution intraperitoneally, and 70% for the group given peplomycin solution intramuscularly. Five weeks after administration the mice were killed, and the grade and the incidence of pulmonary fibrosis were evaluated histologically. The grade and incidence of pulmonary fibrosis were zero in the two groups given PEP-CH. The grade was 0.33 and 1.76, and the incidence was 60% and 86%, respectively, in the group given peplomycin solution intraperitoneally and in the group given peplomycin solution intramuscularly.