Product number: 7688

Cetrimide Agar (Agar Medium N) is used in the isolation and identification of Pseudomonas aeruginosa. Conforms to Harmonized USP/EP/JP Requirements in a laboratory setting. Cetrimide Agar (Agar Medium N) is not intended for use in the diagnosis of disease or other conditions in humans.

Pseudomonas aeruginosa produces a number of water-soluble pigments, including the yellow-green or yellow-brown fluorescent pigment pyoverdin (fluorescein). When pyoverdin combines with the blue water-soluble pigment pyocyanin, the bright green color characteristic of Pseudomonas aeruginosa is created. Agar containing Cetrimide have successfully isolated Pseudomononas aeruginosa from contaminated samples.

King, Ward, and Raney developed Medium A to enhance the production of pyocyanin in Pseudomonas spp. Cetrimide Agar is prepared according to this formula with the addition of Cetrimide. Cetrimide Agar is recommended in the examination of food and in United States Pharmacopeia (USP XXIII) for use in Microbial Limit Test. Cetrimide Agar is also recommended in the European Pharmacopeia and Japanese Pharmacopoeia (JP) for use in the examination of non-sterile products for specific microorganisms.


Formula Liter
Enzymatic Digest of Gelatin 20 g
Magnesium Chloride 1.4 g
Potassium Sulfate 10 g
Cetrimide (Cetyltrimethylammonium Bromide) 0.3 g
Agar 13.6 g

Final pH: 7.2 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.

Supplement / Liter

Glycerol, 10 mL


  1. Suspend 45.3 g of the medium and 10 mL of glycerol in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Autoclave at 121°C for 15 minutes.

Order Details

Product # Product Description
7668A Cetrimide Agar (Agar Medium N), 500 g

Reference Material

7688 - Cetrimide Agar (Agar Medium N), Product Information Sheet [English] [Portuguese]
7688 - Cetrimide Agar (Agar Medium N), Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Italian] [Spanish, Mexico] [Swedish]

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