Dextrin
»Dextrin is starch,or partially hydrolyzed starch,modified by heating in a dry state,with or without acids,alkalies,or pHcontrol agents.During heating,moisture may be added.
Packaging and storage— Preserve in well-closed containers.
Botanic characteristics—
Microscopic— Granules similar in appearance to the starch from which the Dextrin has been prepared,except that when prepared from cornstarch many of the granules show concentric striations and when prepared from potato starch concentric striations are not clearly visible,the hilum is frequently bicleft,and a small proportion of the granules are distorted.
Identification—
A: Suspend about 1g in 20mLof water,and add a few drops of iodine TS:a blue to reddish brown color results.
B: Dextrin is very soluble in boiling water,forming a mucilaginous solution (difference from starch).
Loss on drying á731ñ— Dry it at a pressure not exceeding 100mm of mercury at 120for 4hours:it loses not more than 13.0%of its weight.
Acidity— Add 10.0g to 100mLof 70percent alcohol,previously neutralized to phenolphthalein,shake for 1hour,filter,and titrate 50mLof the filtrate with 0.10Nsodium hydroxide:not more than 3.0mLis required.
Residue on ignition á281ñ: not more than 0.5%.
Chloride á221ñ— Dissolve 3.0g in 75mLof boiling water,cool,dilute with water to 75mL,and filter if necessary.To 25mLof this solution add 2mLof nitric acid and 1mLof silver nitrate TS:any turbidity produced is not greater than that of a control containing 2.8mLof 0.020Nhydrochloric acid (0.2%).
Protein: not more than 1.0%,when determined as directed under Nitrogen Determination á461ñ,using a 10-g specimen instead of 1g,and 60mLof sulfuric acid instead of 20mL,and multiplying the percentage of nitrogen found by 6.25.
Reducing sugars— To a quantity of Dextrin equivalent to 2.0g on the dried basis add 100mLof water,shake for 30minutes,dilute with water to 200mL,accurately measured,and filter.To 10.0mLof alkaline cupric tartrate TSadd 20.0mLof the filtrate,mix,and heat on a hot plate adjusted to bring the solution to a boil in 3minutes.Boil for 2minutes,and cool quickly.Add 5mLof potassium iodide solution (3in 10)and 10mLof 2Nsulfuric acid,mix,and titrate immediately with 0.1Nsodium thiosulfate VS,using starch TS,added towards the end of the titration,as indicator.Repeat the procedure beginning with “To 10mLof,”using,in place of the filtrate,20mLof a 1in 1000solution of anhydrous dextrose,accurately prepared.Perform a blank titration.(VB-VU)is not greater than (VB-VS),in which VB,VU,and VSare the number of mLof 0.1Nsodium thiosulfate consumed in the titrations of the blank,the Dextrin and the dextrose,respectively (10%,calculated as dextrose,C6H12O6).
Auxiliary Information— Staff Liaison:Daniel K.Bempong,Ph.D.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 2995
Pharmacopeial Forum:Volume No.28(2)Page 411
Phone Number:1-301-816-8143