ANTIBIOTIC ASSAY MEDIUM NO. 8 (as per USP)

The composition of this medium is in accordance to USP and CFR and identical numerically with the name assigned by Grove and Randall. This medium provides the optimal pH 5.9 for assay of tetracycline as these antibiotics are stable at slightly lower pH. This pH condition also supports the growth of test organisms. This medium is also used as base and seed agar medium for agar diffusion assay for mitomycin, mithramycin, plicamycin and Vancomycin
To perform the antibiotic assay, the Base Agar should be prepared on the same day as the test. The potency of an antibiotic can be demonstrated by its inhibitory effect on microorganisms under suitable conditions. For the cylinder method, a base layer of 21 ml is required. Once the base medium has solidified, seed layer inoculated with the standardized test culture can be overlaid. Even distribution of the layer is important.

for microbiological assay of Mitomycin, Plicamycin and Vancomycin