Cinoxacin: effectiveness against experimental pyelonephritis in rats.

The antimicrobial activity of cinoxacin, 1-ethyl-4(1H)-oxo-[1,3]dioxolo[4,5-g]cinnoline-3-carboxylic acid, previously reported as compound 64716, was determined and compared with other antimicrobial agents at a dosage of 12 mg/kg once daily in a descending pyelonephritis rat model with Escherichia coli and Proteus mirabilis as infecting organisms. Cinoxacin was considerably more effective than either nalidixic acid or oxolinic acid when all three were administered orally at 3 mg/kg four times daily. The presence of demonstrable serum activity with a high recovery in urine indicates cinoxacin possesses highly desirable properties of an effective oral chemotherapeutic agent for urinary tract infections.