Placental transmission of colistimethate

Abstract

Interest in the transmission of drugs from mother to fetus is now oriented toward rate of transmission rather than mere presence. Interest in the activity of transferred antibiotics in the fetus is directed toward therapeutic and toxic effects. One therapeutic effect of importance is the prevention of intrauterine infection in the case of premature rupture of the membranes. 5 Numerous toxic effects of antibiotics on the developing fetus have resulted from transplacental transfer. s , 9,16 Most of the antibiotics previously studied have had molecular weights of 440 or less. The present study deals with the maternal and fetal distribution of sodium colistimethate (Colistin, Coly-Mycin), a polypeptide antibiotic with a molecular weight Received for publication Jan. 23, 1967. 578of the order of 1,200. Interest in its transfer stems from use in the treatment of urinary tract infections in the female, 2, 10, 29 nephrotoxicity,12, 13, 17, 21, 24 and neurotoxicity.33, 34, 36 Through its antimicrobial activity, this drug makes possible the study of the transfer of a polypeptide from mother to fetus without the use of radioactive materials. Materials and methodsTwo preparations of the antibiotic," 150 mg. (base activity) sodium colistimethate (WI929-41) buffered with 10 mg. citric acid and 50 mg. sodium citrate, and 150 mg. (base activity) lyophilized sodium colistimethate (WI929-46 ), were used.

Placental Transfer of Drugs Administered to the Mother

“…Incomplete transfer of chloramphenicol has also been described by Charles)}3] Colistimethate Colistimethate IS0mg was administered intravenously to 112 patients at term. [120] Colistimethate has an incomplete transfer across the placenta. The rate of elimination of colistimethate was greater in the mother than in the fetus.…”