Tapioca Starch »Tapioca Starch consists of the starch granules separated from the tubers of tapioca (cassava)[Manihot utilissimaPohl (Fam.Euphorbiaceae)]. Packaging and storage— Preserve in well-closed containers. Botanic characteristics— Examine Tapioca Starch under a microscope,using not less than 20×magnification and using glycerin as the mounting agent:it appears as spherical granules with one truncated side,typically having a 5-to 35-µm diameter and having circular or several-rayed central clefts. Identification— A: Suspend 1g of Tapioca Starch in 50mLof water,boil for 1minute,and cool:a thin,cloudy mucilage is formed. B: To 10mLof the mucilage obtained in Identificationtest Aadd 0.04mLeach of iodine and potassium iodide TS:a reddish violet to dark blue color is produced,which disappears on heating and reappears on cooling. Microbial limits á61ñ It meets the requirements of the test for absence of Escherichia coli.The total aerobic microbial count does not exceed 1000cfu per g,and the total combined molds and yeasts count does not exceed 100cfu per g. pHá791ñ Weigh 20.0±0.1g of Tapioca Starch,transfer to a suitable nonmetallic container,and add 100mLof water to obtain a slurry.Agitate continuously at a moderate rate for 5minutes,then stop agitation,and immediately determine the pH:between 4.5and 7.0. Loss on drying á731ñ Dry it at 130for 90minutes:it loses not more than 16.0%of its weight. Residue on ignition á281ñ: not more than 0.6%,determined on a 1.0-g specimen. Iron á241ñ: 0.002%,the Test preparationbeing prepared as follows.Shake 0.25g of Tapioca Starch with 15mLof 0.1Nhydrochloric acid,and filter.Use 10mLof this solution as the Test preparation. Limit of oxidizing substances— Transfer 4.0g of Tapioca Starch to a glass-stoppered,125-mLconical flask,and add 50.0mLof water.Insert the stopper,and swirl for 5minutes.Decant into a glass-stoppered,50-mLcentrifuge tube,and centrifuge to clarify.Transfer 30.0mLof the clear supernatant to a glass-stoppered,125-mLconical flask.Add 1mLof glacial acetic acid and 0.5to 1.0g of potassium iodide.Insert the stopper,swirl,and allow to stand for 25to 30minutes in the dark.Add 1mLof starch TS,and titrate with 0.002Nsodium thiosulfate VSto the disappearance of the starch-iodide color.Perform a blank determination,and make any necessary correction (see Titrimetry á541ñ).Each mLof 0.002Nsodium thiosulfate is equivalent to 34µg of oxidant,calculated as hydrogen peroxide.Not more than 1.4mLof 0.002Nsodium thiosulfate is required:not more than 0.002%of oxidizing substances is found. Limit of sulfur dioxide— Mix 20g of Tapioca Starch with 200mLof water until a smooth suspension is obtained,and filter.To 100mLof the clear filtrate add 3mLof starch TS,and titrate with 0.01Niodine solution VSto the first permanent blue color.Not more than 1.7mLis consumed:not more than 0.005%of sulfur dioxide is found. Auxiliary Information— Staff Liaison:Justin Lane,B.S.,Scientific Associate Expert Committee:(EMC)Excipients:Monograph Content USP28–NF23Page 3090 Pharmacopeial Forum:Volume No.30(5)Page 1672 Phone Number:1-301-816-8323