DISTRIBUTION AND METABOLISM OF PENTOXIFYLLINE IN NON-TUMOR-BEARING MICE

Pentoxifylline increases tissue oxygen delivery in patients, with athe rosclerotic arterial disease by several mechanisms, including lowering blood viscosity and increasing erythrocyte flexibility. Since tumor n eo-vessels are also abnormal and associated with intra-tumoral hypoxia and, thus, with radiation failure, pentoxifylline might also be usefu l as a radiation sensitizer. The mouse is frequently used to study suc h drugs, but the pharmacokinetics of pentoxifylline in the mouse have not been determined. We investigated this in three separate experiment s by administering pentoxifylline intraperitoneally, subcutaneously, o r orally. Plasma was assayed for the parent drug and its metabolites b y capillary gas chromatography. High plasma levels of pentoxifylline a nd both major derivatives occurred within several minutes after intrap eritoneal or subcutaneous injection, but plasma levels were low after oral administration.