Dehydrated culture media
Antibiotic Medium No. 12
Medium used to assay amphotericin B.
- Cat. No.
- LC-1525
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Standards
- European PharmacopoeiaUSP
Antibiotic Medium No. 12 is recommended for preparing test plates for the cylinder plate assay of the antifungal agents nystatin and anisomycin, using only Saccharomyces cerevisiae as the test organism. It is used for the assay of amphotericin B.
Key features
Applications
Antibiotic assay (general use).
Industry
Pharmaceutical/veterinary.
Standards
European Pharmacopoeia, USP.
Preparation
60 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Peptone and beef extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly the B-group. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Dextrose is the fermentable carbohydrate providing carbon and energy. Bacteriological agar is the solidifying agent.
The potency of an antibiotic can be demonstrated under appropriate conditions by its inhibitory effect on microorganisms. This method is based on the diffusion of an antibiotic solution from a cylinder placed on the surface of an inoculated agar medium. The diameter of an inhibition zone after incubation depends, in part, on the concentration or activity of the antibiotic.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber, slightly opalescent |
| Final pH (25 °C) | 6.1 ± 0.1 |
| Amount per litre | 60 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 23.5 |
| Beef extract | 2.4 |
| Dextrose | 10 |
| Peptone | 9.4 |
| Sodium chloride | 10 |
| Yeast extract | 4.7 |
Preparation and use
Preparation
Suspend 60 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
- Spread the inoculum onto the base layer.
- The cylinders are placed on the surface of the inoculated medium, filled with the reference antifungal solutions.
- Incubate at 30 ± 2 °C and observe for 40-48 hours.
Quality control
Microbiological test
Incubation conditions: 35-37 °C / 40-48 h.
| Microorganism | Specification |
|---|---|
| Saccharomyces cerevisiaeATCC 9763 | Good growth |
Bibliography
- United States Pharmacopeial Convention, Inc. 2001. The United States Pharmacopeia 25/The National Formulary 20-2002. United States Pharmacopeial Convention, Inc., Rockville, Md.
- Abraham, Chain, Fletcher, Florey, Gardner, Heatley and Jennings. 1941. Lancet II 177.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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Tracked shipment
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