Antibiotic Assay Medium 11 (Neomycin Erythromycin Assay Agar) is a standardized high pH culture medium formulated for microbiological antibiotic potency testing using cylinder plate or disk diffusion assay methods. Each 500mL bottle contains a carefully balanced agar base composed of peptones, yeast extract, and beef extract adjusted to a final pH of approximately 8.3. This alkaline environment enhances the activity and stability of basic antibiotics such as Neomycin, Erythromycin, and related aminoglycosides, ensuring accurate potency determination. The nutrient composition promotes consistent growth of assay organisms including Micrococcus luteus and Staphylococcus epidermidis, producing well defined zones of inhibition. These clear zones allow precise measurement of antibiotic concentration and support pharmaceutical manufacturing quality control and regulatory testing protocols.