Modified Starch
» Modified Starch is Starch modified by chemical means. Food Starch may be acid-modified, bleached, oxidized, esterified, etherified, or treated enzymatically to change its functional properties (21 CFR 172.892).
Packaging and storage— Preserve in well-closed containers. No storage requirements specified.
A: Corn starch:polygonal, rounded, or spheroidal granules up to about 35 µm in diameter and usually having a circular or several-rayed central cleft.
Tapioca starch: spherical granules with one truncated side, typically 5 to 35 µm in diameter and usually having a circular or several-rayed central cleft.
Potato starch: irregularly shaped, ovoid, or pear-shaped granules, usually 30 to 100 µm in size but occasionally exceeding 100 µm; or rounded, 10 to 35 µm in size. There are occasional compound granules having two to four components. The ovoid and pear-shaped granules have an eccentric hilum, and the rounded granules have an accentric or slightly eccentric hilum. All granules show clearly visible concentric striations.
Wheat starch: large and small granules, usually 10 to 60 µm in diameter. The central hilum and striations are visible or barely visible.
B: Prepare a 2% (w/w) sodium hydroxide solution. Weigh 0.6 g of Modified Starch, and transfer to a 25-mL glass vial with a plastic cap. Add 9.4 g of water, cap, and shake vigorously to evenly disperse the starch. Add 10 g of 2% sodium hydroxide solution, cap, and shake vigorously for 1 minute to create a smooth mixture. Evaluate within 1 minute. The final solution is translucent to opaque with a fluid consistency. A yellow tint of the final solution is acceptable.
C: A water slurry of the Modified Starch is colored orange-red to deep blue by iodine TS.
Microbial enumeration tests 61 and Tests for specified microorganisms 62 It meets the requirements of the tests for absence of Salmonella species and Escherichia coli. The total aerobic microbial count does not exceed 1000 cfu per g; the total combined molds and yeasts count does not exceed 100 cfu per g.
pH 791 Weigh 20.0 ± 0.1 g of Modified Starch, transfer to a suitable nonmetallic container, and add 100 mL of water to obtain a slurry. Stir using a magnetic stirrer at a moderate rate for about 5 minutes, and determine the pH to the nearest 0.1 unit: between 3.0 and 9.0.
Loss on drying 731 Dry it at 120 for 4 hours. Corn starch and Wheat starch: not more than 15.0%; Tapioca starch: not more than 18.0%; and Potato starch: not more than 21.0%.
Residue on ignition 281: not more than 1.5%, a test specimen of 2.0 ± 0.1 g being used.
Iron 241: 0.002%, the Test Preparation being prepared as follows. Dissolve the residue obtained in the test for Residue on ignition in 8 mL of hydrochloric acid with the aid of gentle heating. Dilute with water to 100 mL in a volumetric flask, and mix. Dilute 25 mL of this solution with water to 47 ± 1 mL.
Oxidizing substances— Transfer 4.0 g to a glass-stoppered, 125-mL conical flask, and add 50.0 mL of water. Insert the stopper, and swirl for 5 minutes. Transfer to a glass-stoppered, 50-mL centrifuge tube, and centrifuge to clarify. Transfer 30.0 mL of the clear supernatant to a glass-stoppered, 125-mL conical flask. Add 1 mL of glacial acetic acid and 0.5 g to 1.0 g of potassium iodide. Insert the stopper, swirl, and allow to stand for 25 to 30 minutes in the dark. Add 1 mL of starch TS, and titrate with 0.002 N sodium thiosulfate VS to the disappearance of the starch–iodine color. Perform a blank determination, and make any necessary correction. Each mL of 0.002 N sodium thiosulfate is equivalent to 34 µg of oxidant, calculated as hydrogen peroxide. Not more than 12.6 mL of 0.002 N sodium thiosulfate is required (180 µg per g, calculated as H2O2): not more than 0.018% of oxidizing substances is found.
Limit of sulfur dioxide— Mix 20.0 ± 0.1 g of Modified Starch with 200 mL of 5% alcohol until a smooth suspension is obtained, and vacuum-filter through paper (Whatman No.1 or equivalent). To 100 mL of the filtrate add 3 mL of starch TS, and titrate with 0.01 N iodine VS to the first permanent blue color. Not more than 1.7 mL is consumed: not more than 0.005% of sulfur dioxide is found.
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Monograph Hong Wang, Ph.D.
(EM205) Excipient Monographs 2
61 Radhakrishna S Tirumalai, Ph.D.
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(MSA05) Microbiology and Sterility Assurance
62 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
(MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 1355
Pharmacopeial Forum: Volume No. 30(4) Page 1334