OBJECTIVES: I. Determine the maximum tolerated dose (MTD) of suramin followed by doxorubicin in patients with advanced solid tumors. II. Describe the toxic effects of suramin with sequential doses of doxorubicin in these patients. III. Assess the development of peripheral neuropathy in patients with this treatment. IV. Assess the preliminary evidence of the antitumor effect of this regimen in these patients. VI. Explore the relationships between the pharmacokinetic parameters and potential neurotoxicity of suramin in these patients.