Microbiological assay for enrofloxacin injection.

A simple, sensitive and specific agar diffusion bioassay for the antibacterial enrofloxacin was developed. Using a strain of Staphylococcus aureus ATCC 6538P as the test organism, enrofloxacin at concentrations ranging from 3.2 to 12.8 microg ml(-1) could be measured in injection. A prospective validation of the method showed that method was linear (r = 0.99998), precise (R.S.D. = 0.27) and accurate (it measured the added quantities). The method shows results that confirm its precision, not differing significantly the other method described in the literature. We conclude that microbiological assay is satisfactory for quantitation of in vitro antibacterial activity of enrofloxacin.