| Abstract: | Aztreonam was given orally to eight healthy volunteers in two different dosage regimens. To determine the concentration of aztreonam in faecal specimens a method was established using reversed-phase high pressure liquid chromatography (HPLC). Comparison of microbiological and HPLC assays showed a linear relationship between both techniques which, however, was not 1:1. The microbiological assay tended to yield higher aztreonam levels than the HPLC method. The HPLC assay for aztreonam proved to be five-fold less sensitive than the bioassay; however, since in most cases high aztreonam levels were found in the faeces of the test subjects, this was not a disadvantage. The HPLC assay was much easier to perform than the bioassay and yielded easily quantifiable results in a wider concentration range. In the stool specimens of one volunteer no aztreonam could be detected by either method, indicating inactivation and/or degradation of the compound. |
