[Therapeutic effect of an antineoplastic agent (peplomycin) adsorbed on activated charcoal (PEP-AC)]

Therapeutic effects of PEP-AC and PEP-saline on pulmonary growth of intratracheally implanted tumor and metastasis into the hilar lymph nodes were studied in mice. Pharmacokinetic studies of PEP-AC and PEP-saline were made by autoradiography (ARG) using 3H-PEP and microbial assay method using B. subtilis. The ARG using 3H-PEP-AC and 3H-PEP-saline demonstrated qualitatively slower elimination of PEP-AC from mouse lung than that of PEP-saline. The half-life time (t1/2) of PEP-AC was estimated to be about 3 days by bioassay method, while about 60 min. was given for PEP-saline. Intratracheal administration of PEP-saline produced no therapeutic effect to pulmonary growth of B16 melanoma, while that of PEP-AC gave a good response depending on doses. Furthermore, PEP-AC inhibited metastasis of B16 melanoma into the hilar lymph nodes. Better therapeutic effects were produced by PEP-AC when decreased inoculum sizes of B16 melanoma or P388 leukemia cells were transplanted.