Overview:
Antibiotic Medium No. 13 is the official liquid medium used for the preparation of spore suspensions and inoculum of Candida albicans and Saccharomyces cerevisiae in the compendial cylinder-plate assay of nystatin and amphotericin B. It is designated as �Medium N� in USP <81>, European Pharmacopoeia 2.7.2, JP 17, and WHO guidelines. The classic Sabouraud formulation with 2% glucose and slightly acidic pH (5.6�5.8) promotes rapid and heavy growth of yeasts while maintaining excellent spore viability.
Applications:
?? Preparation of standardized yeast inoculum for nystatin and amphotericin B potency assays
?? Growth and maintenance of Candida albicans ATCC 10231 and Saccharomyces cerevisiae ATCC 9763
?? Compendial antifungal microbiological assays (cylinder-plate method)
?? Pharmaceutical QC laboratories
Key Features:
?? Classic Sabouraud formulation with 2% glucose
?? Acidic pH (5.7) � optimal for yeast growth and spore production
?? Internationally harmonized (USP/EP/JP/WHO)
?? Reference broth for all official polyene antifungal assays
Composition (per liter):
Peptone (meat or casein)� 10.0 g
D-Glucose (Dextrose)� 20.0 g
Final pH: 5.7 � 0.1 at 25�C (after sterilization)
Preparation:
Dissolve 10.0 g peptone and 20.0 g glucose in 1 liter of purified water. Mix thoroughly until completely dissolved. Dispense into tubes or flasks as required. Sterilize by autoclaving at 121�C for 15 minutes. Cool to room temperature.
Usage in assay:
Inoculate with a small amount of fresh culture of Candida albicans ATCC 10231 or Saccharomyces cerevisiae ATCC 9763. Incubate at 30�35�C for 24�48 hours. Wash and dilute the resulting growth to obtain the standardized spore suspension for seeding Antibiotic Medium No. 12 or other assay plates.
Storage:
Dehydrated components or prepared broth: Store at room temperature, protected from light.
Prepared medium: Stable for 3 months at 2�8�C.
For pharmaceutical quality-control and official compendial antifungal assay only.