Use of sodium polyanethol sulfonate to selectively inhibit aminoglycoside and polymyxin antibiotics in a rapid blood level antibiotic assay.

Sodium polyanethol sulfonate inhibits aminoglycoside and polymyxin classes of antibiotics in direct proportion to its concentration. Aminoglycoside and polymyxin class antibiotics are selectively inactivated; penicillin, including the semisynthetic penicillins, cephalothin, chloramphenicol, clindamycin, tetracycline, erythromycin, and vancomycin are not inhibited. By incorporating sodium polyanethol sulfonate directly into the test medium it is possible, in a 4-h antibiotic blood level assay, to selectively obviate the activity of the aminoglycosides and polymyxins to determine the concentration of other antibiotics present in the same serum sample.