Bleomycin

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Bleomycin is an antineoplastic antibiotic. The drug is active against gram-positive and gram-negative bacteria and fungi, but its cytotoxicity precludes its use as an anti-infective agent. The precise mechanism(s) of action of bleomycin is not fully known. Several studies in Escherichia coli and HeLa cells suggest that the drug inhibits the incorporation of thymidine into DNA. In these in vitro studies, DNA synthesis was inhibited to a greater extent than was RNA or protein synthesis. Bleomycin also appears to labilize the DNA structure, resulting in scission of both single- and double-stranded DNA. The drug has no immunosuppressive activity in mice

Bleomycin sulfate is a mixture of basic cytotoxic glycopeptide antibiotics produced by Streptomyces verticillus; bleomycin A₂ and bleomycin B₂ are the major components. Bleomycin sulfate occurs as a cream-colored, amorphous powder and is very soluble in water and sparingly soluble in alcohol. The potency of bleomycin is assayed microbiologically; the activity of 1 unit of bleomycin is equivalent to the activity of 1 mg of bleomycin A₂ reference standard. Following reconstitution, bleomycin sulfate injection has a pH of 4.5–6, depending upon the diluent used

Currently, antibiotic therapies using bleomycin are indicated in patients with Hodgkin's lymphoma, testicular tumor and Wilms' tumor, among others. Furthermore, in the course of studying the chemically complex structure of bleomycin, researchers were able to clarify the mechanisms that made it effective, and to develop techniques for antibiotic synthesis and biosynthesis that led to the development of peplomycin, a less toxic derivative with a wide antitumor spectrum that was introduced in 1981 for the treatment of prostatic cancer.