Tannic Acid
Tannic acid;Tannin [1401-55-4]. »Tannic Acid is a tannin usually obtained from nutgalls,the excrescences produced on the young twigs of Quercus infectoriaOliver,and allied species of QuercusLinné(Fam.Fagaceae),from the seed pods of Tara (Caesalpinia spinosa),or from the nutgalls or leaves of sumac (any of a genus Rhus). Packaging and storage— Preserve in tight,light-resistant containers. Identification— A: To 2mLof a solution (1in 10)add 1drop of ferric chloride TS:a bluish black color or precipitate results. B: To a solution (1in 10)add an equal volume of gelatin solution (1in 100):a precipitate is formed. Loss on drying á731ñ Dry it at 105for 2hours:it loses not more than 12.0%of its weight. Residue on ignition á281ñ: not more than 1.0%. Arsenic,Method IIá211ñ: 3ppm. Heavy metals,Method IIá231ñ: 0.004%. Gum or dextrin— Dissolve 2g in 10mLof hot water:the solution is not more than slightly turbid.Cool,filter,and divide the filtrate into two equal portions.To one portion add 10mLof alcohol:no turbidity is produced. Resinous substances— To a portion of the filtrate obtained in the test for Gum or dextrinadd 10mLof water:no turbidity is produced. Organic volatile impurities,Method Iá467ñ: meets the requirements. Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist Expert Committee:(PA6)Pharmaceutical Analysis 6 USP28–NF23Page 1848 Phone Number:1-301-816-8389