[Myelotoxicity of high-molecular-weight poly(ethylene oxide)]

The effects of administration of the parent substance of high-molecular-weight poly(ethylene oxide) (HMWPEO) with a molecular mass of 3-6 x 10(6) D and the related drug polyetox (representing a water-soluble lyophilized form of HMWPEO suitable for intravenous injection) on the characteristics of peripheral blood and bone marrow were studied in rats. HMWPEO was injected intravenously and intraperitoneally in a single toxic dose. Polyetox was injected intraperitoneally in a therapeutic dose and in 3- and 10-fold doses over a period of 30 days. Single i.v. and i.p. injections of HMWPEO in the maximum tolerable dose leads to a dose-dependent reversible hemolytic anemia of medium degree, neutrophilic leukocytosis, lymphopenia, and thrombocytopenia. The chronic i.p. adminstration of polyetox in a 10-fold therapeutic dose caused red blood cell lysis and led to the development of reversible regenerative anemia.