(a' gar).
Add the following:
Change to read:
Agar is the dried, hydrophilic, colloidal substance consisting of the polysaccharidesNF30 extracted from Gelidium cartilagineum (Linné) Gaillon (Fam. Gelidiaceae), Gracilaria confervoides (Linné) Greville (Fam. Sphaerococcaceae), and related red algae (Class Rhodophyceae).
Add the following:
•  A. Infrared Absorption 197K NF30
Change to read:
•  B.NF30 Iodine TS colors some of the fragments of Agar bluish black, with some areas reddish to violet.
Change to read:
•  C.NF30
Analysis:  Boil a sample with 65 times its weight of water for 10 min, with constant stirring, and subsequentlyNF30 adjust with hot water to a concentration of 1.5%, by weight.
Acceptance criteria:  Agar forms a clear liquid that congeals at 30NF30–39 to form a firm resilient gel, which does not liquefy below 80.NF30
Inorganic Impurities 
•  Arsenic, Method II 211: NMT 3 ppm
•  Lead 251: NMT 10 ppm
•  Heavy Metals, Method II 231: NMT 40 ppm
•  Articles of Botanical Origin, Acid-Insoluble Ash 561: NMT 0.5%, on a dry-weight basis
Change to read:
Organic Impurities 
•  Procedure 1: Limit of Gelatin
Sample solution:  Dissolve 1 g of sample in 100 mL of boiling water. Allow to cool to about 50.
Analysis:  To 5 mL of the Sample solution add 2–3 drops of a mixture of 0.2 M potassium dichromate solution and 3 N hydrochloric acid (4:1).
Acceptance criteria:  No yellow precipitate is formed.
•  Procedure 2: Limit of Foreign Starch
Sample solution:  Boil 0.10 g in 100 mL of water.
Acceptance criteria:  The Sample solution does not, upon cooling, produce a blue color upon the addition of iodine TS.
•  Procedure 3: Limit of Foreign Insoluble Matter
Sample dispersion:NF30  Add sufficient water to 7.5 g of sample to make 500 g, boil for 15 min, and readjust to the original 500 g.
Analysis:  To 100 g of the uniformly mixed Sample dispersionNF30 add hot water to make 200 mL. Heat almost to boiling, filter while hot through a tared filtering crucible. Rinse the container with several portions of hot water, and pass these rinsings through the crucible. Dry the crucible and its contents at 105 to a constant weight.
Acceptance criteria:  NMT 15 mg (1.0%) remains in the crucible.
Change to read:
•  Microbial Enumeration Tests 61 and Tests for Specified Microorganisms 62: The total aerobic microbial count does not exceed 103 cfu/g, and the total combined molds and yeasts count does not exceed 102 cfu/g. It meets the requirements of the tests for absence of Salmonella species and Escherichia coli.NF30
•  Water Determination, Method III 921
Analysis:  If necessary, cut a sample into pieces from a 2- to 5-mm square, and dry at 105 for 5 h.
Acceptance criteria:  The sample loses NMT 20.0% of its weight.
•  Articles of Botanical Origin, Total Ash 561: NMT 6.5%, on a dry-weight basis
•  Water Absorption
Sample:  5.0 g
Analysis:  Place the Sample in a 100-mL graduated cylinder, fill to the mark with water, mix, and allow to stand at 25 for 24 h. Pour the contents of the cylinder through moistened glass wool, allowing the water to drain into a second 100-mL graduated cylinder.
Acceptance criteria:  NMT 75 mL of water is obtained.
Change to read:
•  Botanic Characteristics
Agar:  Usually occursNF30 in bundles consisting of thin, membranous, agglutinated strips or in cut, flaked, or granulated forms. It may be coloredNF30 weak yellowish orange, yellowish gray to pale yellow, or colorless. It isNF30 tough when damp, brittle when dry.
Histology:  When mounted in water,NF30 Agar appears granular and somewhat filamentous; a few fragments of the spicules of sponges and a few frustules of diatoms may be present. In Japanese Agar, the frustules of Arachnoidiscus ehrenbergii Baillon often occur, being disk-shaped and 100–300 µm in diameter.
Powdered agar:  White to yellowish white or pale yellow; in chloral hydrate TS, its fragments are transparent, more or less granular, striated, and angular, and occasionally they contain frustules of diatoms.
Add the following:
•  Packaging and Storage: Preserve in well-closed containers. No storage requirements are specified.NF30
Add the following:
•  USP Reference Standards 11
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
61 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
(GCM2010) General Chapters - Microbiology
62 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
(GCM2010) General Chapters - Microbiology
Reference Standards RS Technical Services
USP35–NF30 Page 1685
Pharmacopeial Forum: Volume No. 33(4) Page 702