Histamine Phosphate
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1H-Imidazole-4-ethanamine,phosphate (1:2).
Histamine phosphate (1:2) [51-74-1].
»Histamine Phosphate contains not less than 98.0percent and not more than 101.0percent of C5H9N3·2H3PO4,calculated on the dried basis.
Packaging and storage—
Preserve in tight,light-resistant containers.
Identification—
A:
Dissolve 0.10g in a mixture of 7mLof water and 3mLof 1Nsodium hydroxide,and add the solution to a mixture of 50mg of sulfanilic acid,10mLof water,2drops of hydrochloric acid,and 2drops of sodium nitrite solution (1in 10):a deep red color is produced.
B:
Dissolve 50mg in 5mLof hot water,add a hot solution of 50mg of picrolonic acid in 10mLof alcohol,and allow to crystallize.Filter the crystals with suction,wash with a small amount of ice-cold water,and dry at 105
for 1hour:the crystals so obtained melt between 250and 254,with decomposition.
for 1hour:the crystals so obtained melt between 250and 254,with decomposition.
C:
Asolution (1in 10)responds to the tests for Phosphate á191ñ.
Loss on drying á731ñ—
Dry it at 105for 2hours:it loses not more than 3.0%of its weight.
for 2hours:it loses not more than 3.0%of its weight.
Assay—
Dissolve about 150mg,accurately weighed,of Histamine Phosphate in 10mLof water.Add 5mLof chloroform and 25mLof alcohol,then add 10drops of thymolphthalein TS,and titrate with 0.2Nsodium hydroxide VS.Each mLof 0.2Nsodium hydroxide is equivalent to 15.36mg of C5H9N3·2H3PO4.
Auxiliary Information—
Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 946
Pharmacopeial Forum:Volume No.29(5)Page 1504
Phone Number:1-301-816-8251