Bioassay procedures for norfloxacin.

A disk-diffusion bioassay procedure for the quantitation of norfloxacin in serum, tissue and urine employing Klebsiella pneumoniae ATCC 10031 was developed. When incubated at 28 degrees C, the assay has a sensitivity of 0.2 microgram/ml. Zones of inhibition on assay plates may be measured by hand (ruler, vernier caliper) or by automated image analysis. Urine samples require an initial 1:2 dilution in 0.1N HCl before assay to assure complete solution of the compound. Bioassay values in urine are comparable to those obtained by high performance liquid chromatography.