Antibiotic assay media are used for determining antibiotic potency by the microbiological assay technique.

• Potency is tested by demonstrating its inhibitory effect

Antibiotic medium 1 and antibiotic medium 4 are used in a cylinder plate method for detecting penicillin in nonfat dry milk.

Antibiotic medium 12 is prepared with the grove and randall formula. It is used for the assay of amphotericin B. Recommended for use in preparing test plates for the cylinder plate assay of nystatin and anisomycin.

Antibiotic medium 19 corresponds to the use described in outline of details for official microbiological assays of antibiotics

Cylinder plate assays are used for commercial preparations of antibiotics, as well as in the quantitative determination of antibioitics in body fluids, animal feeds, and other materials.