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PubMedDate not supplied

Identification of microsomal metabolites of spirogermanium.

In the present study we report on the identification of two novel microsomal metabolites of the investigational anticancer agent Sprigermanium (NSC-192965). The two metabolites were isolated after incubation of Spirogermanium with fortified rat liver microsomes. Mass spectrometry studies indicate that one of them, formed in major quantities, is hydroxy Spirogermanium. The other metabolite appears to correspond to bis-desmethylated Spirogermanium.

Animals↗
PubMed1989

Pharmacological activities of spirogermanium and other structurally related azaspiranes: effects on tumor cell and macrophage functions.

Spirogermanium is a germanium containing azaspirane which has been shown to have activity in experimental models of cancer and immune dysfunction. A series of analogs of the parent compound were synthesized and evaluated in a number of in vitro and in vivo biological assays to define the structure-activity relationships of this class of compounds relative to their potential therapeutic activities. In a colony-forming assay using HT-29 human colon carcinoma cells various analogs in which carbon replaced germanium (e.g. carbon) retained the potent cytotoxic activity in vitro seen with spirogermanium. Increased cytotoxic potency within the group of carbon containing analogs was directly related to increase in the length of the alkyl group(s) attached to the carbon atom opposite the azaspirane ring structure. DNA and protein synthesis by HT-29 cells was inhibited by these compounds. However, inhibition occurred only at supralethal concentrations or after long exposure times with the drug. None of the azaspiranes demonstrated in vivo anti-tumor activity against P388 leukemia or ADJ-PC6 plasmacytoma. The effect of these compounds on macrophage cell function was evaluated in vitro by their ability to modulate superoxide (O2-) production by macrophages. Spirogermanium inhibited the production of O2- by activated macrophages with an IC50 of 5 microM. Although macrophage viability did not appear to be decreased at the respective IC50 concentrations, the rank order potency for the analogs in the O2- production assay was directly proportional to that measured for their cytotoxic potency in the HT-29 colony formation assay. The results demonstrate that, within this class of compounds, (1) potent biological activity does not require the presence of germanium in the structure; (2) in vitro cytotoxic activity does not appear to be a direct result of the inhibition of macromolecular synthesis, and (3) macrophage function can be modulated in vitro at non-cytotoxic concentrations. These results are discussed in context with the reported anti-tumor activity of spirogermanium and the potential anti-arthritic and immunomodulatory activity of this class of compounds.

Animals↗
PubMed1980

Toxicity of spirogermanium in mice and dogs after iv or im administration.

Toxicity of single-dose spirogermanium was evaluated after iv and im administration to CDF1 mice and beagle dogs. The im LD50 in mice was approximately threefold greater than the iv LD50. The lethal dose in dogs was the same for both routes of administration, but death was delayed after im injection. Convulsive seizures occurred only after the im doses that were lethal, but they were observed after administration of iv doses that were nonlethal. Microscopic evidence of drug toxicity (necrosis and degeneration) was found in mitotically active tissues: intestinal tract, lymphoid tissue, and bone marrow. Necrosis, hemorrhage, edema, and granulation tissue were observed in the muscle injection site.

Animals↗