Bentonite Magma
» Prepare Bentonite Magma as follows:
Bentonite 50 g
Purified Water, a sufficient  
quantity, to make 1000 g
Sprinkle the Bentonite, in portions, upon 800 g of hot purified water, allowing each portion to become thoroughly wetted without stirring. Allow it to stand with occasional stirring for 24 hours. Stir until a uniform magma is obtained, add Purified Water to make 1000 g, and mix.
The Magma may be prepared also by mechanical means such as by use of a blender, as follows. Place about 500 g of Purified Water in the blender, and while the machine is running, add the Bentonite. Add Purified Water to make up to about 1000 g or up to the operating capacity of the blender. Blend the mixture for 5 to 10 minutes, add Purified Water to make 1000 g, and mix.
Packaging and storage— Preserve in tight containers.
Microbial enumeration tests 61 and Tests for specified microorganisms 62 It meets the requirements of the test for absence of Escherichia coli.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Jeanne H. Sun
Assistant Scientific Liaison
1-301-816-3361
(CMP2010) Compounding
61 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
62 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
USP35–NF30 Page 1708