(jel' a tin).
Gelatin is a product obtained by the partial hydrolysis of collagen derived from the skin, white connective tissue, and bones of animals. Gelatin derived from an acid-treated precursor is known as Type A, and Gelatin derived from an alkali-treated precursor is known as Type B.
Gelatin, where being used in the manufacture of capsules, or for the coating of tablets, may be colored with a certified color, may contain NMT 0.15% of sulfur dioxide, and may contain a suitable concentration of sodium lauryl sulfate and suitable antimicrobial agents.
•  A. Procedure
Sample:  1 g
Analysis:  Dissolve the Sample in 100 mL of hot water. To this solution add 20 mL of a mixture of 0.2 M potassium dichromate and 3 N hydrochloric acid (4:1).
Acceptance criteria:  A yellow precipitate is formed.
•  B. Procedure
Sample solution:  0.2 mg/mL
Analysis:  Heat until hot, and add tannic acid TS.
Acceptance criteria:  Turbidity is produced.
•  Content of Sulfur Dioxide
Sample solution:  Dissolve 20.0 g in 150 mL of hot water in a flask having a round bottom and a long neck, add 5 mL of phosphoric acid and 1 g of sodium bicarbonate, and at once connect the flask with a condenser. [Note—Excessive foaming can be alleviated by the addition of a few drops of a suitable antifoaming agent. ]
Analysis:  Distill 50 mL, receiving the distillate under the surface of 50 mL of 0.1 N iodine. Acidify the distillate with a few drops of hydrochloric acid, add 2 mL of barium chloride TS, and heat on a steam bath until the liquid is nearly colorless.
Acceptance criteria:  The precipitate of barium sulfate, if any, when filtered, washed, and ignited, weighs NMT 3 mg, corresponding to NMT 40 ppm of sulfur dioxide, correction being made for any sulfate that may be present in 50 mL of the 0.1 N iodine.
Gelatin used in the manufacture of capsules or for the coating of tablets yields NMT 109.3 mg of barium sulfate, corresponding to NMT 0.15% of sulfur dioxide.
Inorganic Impurities 
•  Residue on Ignition 281
Sample:  5.0 g
Analysis:  Incinerate without the use of sulfuric acid, but with the addition of 1.5–2.0 g of paraffin to avoid loss due to swelling, then finish ashing in a muffle furnace at 550 for 15–20 h.
Acceptance criteria:  The weight of the residue does not exceed 2.0%.
•  Arsenic, Method I 211
Solution A:  5 mg/mL of pepsin in 0.1 N hydrochloric acid
Standard solution:  Transfer 3.0 mL of Standard Arsenic Solution to an arsine generator flask, and dilute with Solution A to 52 mL. Add 3 mL of hydrochloric acid and 4 mL of isopropyl alcohol.
Sample solution:  Mix 3.75 g with 40 mL of Solution A in an arsine generator flask. Heat cautiously to a temperature between 65 and 70, and, while maintaining this temperature for 30 min, sonicate the solution for 2 min at each 10-min interval of heating time. Cool, wash down the sides of the generator with Solution A, and dilute with Solution A to 52 mL. Add 3 mL of hydrochloric acid and 4 mL of isopropyl alcohol.
Analysis:  Proceed as directed in the chapter, except omit the addition of 20 mL of 7 N sulfuric acid and 1 mL of isopropyl alcohol to the Standard solution and Sample solution.
Acceptance criteria:  The resulting solution from the Sample solution meets the requirements of the test (NMT 0.8 ppm).
•  Heavy Metals 231
Sample:  Residue obtained in the test for Residue on Ignition
Analysis:  To the Sample add 2 mL of hydrochloric acid and 0.5 mL of nitric acid, and evaporate on a steam bath to dryness. To the residue add 1 mL of 1 N hydrochloric acid and 15 mL of water, and warm for a few min. Filter and wash with water to make the filtrate measure 100 mL. Dilute 8 mL of the solution with water to 25 mL.
Acceptance criteria:  NMT 50 ppm
Organic Impurities 
•  Procedure: Odor and Water-Insoluble Substances: A hot solution (1 in 40) is free from any disagreeable odor, and when viewed in a layer 2-cm thick, is only slightly opalescent.
•  Microbial Enumeration Tests 61 and Tests for Specified Microorganisms 62: The total bacterial count does not exceed 1000 cfu/g, and the tests for Salmonella species and Escherichia coli are negative.
•  Packaging and Storage: Preserve in well-closed containers in a dry place.
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Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
61 Radhakrishna S Tirumalai, Ph.D.
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(GCM2010) General Chapters - Microbiology
62 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
(GCM2010) General Chapters - Microbiology
USP35–NF30 Page 1808