Change to read:
Identification
B:
In the test for Chromatographic purity, the principal spot in the chromatogram of Test solution 2, observed after spraying with the ninhydrin solutions, corresponds in RF value, color, and size to that in the chromatogram of Standard solution 1.
Delete the following:
Primary amines and ammonia
Dissolve 500 mg in 10 mL of water. Add 1 mL of 2.5
N sodium hydroxide, 1 mL of acetone, and 1 mL of
sodium nitroferricyanide TS. Mix, and allow to stand for 10 minutes, accurately timed. Determine the absorbance of this solution at 520 nm and at 600 nm, using a blank consisting of the same quantities of the same reagents, but substituting water for the sodium hydroxide solution. The ratio A
600/A
520 is not more than 0.50 (equivalent to about 0.7% of primary amines and ammonia).
USP32
Add the following:
Chromatographic purity
Solvent
Prepare a mixture of 13.5 N ammonium hydroxide and dehydrated alcohol (3:2).
Standard solution 1
Prepare a solution of USP Piperazine Citrate RS in Solvent containing 10 mg per mL.
Standard solution 2
Prepare a solution of ethylenediamine in Solvent containing 0.25 mg per mL.
Standard solution 3
Prepare a solution of triethylenediamine in Solvent containing 0.25 mg per mL.
Test solution 1
Prepare a solution of Piperazine Citrate in Solvent containing 100 mg per mL.
Test solution 2
Mix 1 mL of Test solution 1 and 9 mL of Solvent.
Resolution solution
Prepare a solution in Solvent containing 0.25 mg of triethylamine and 10 mg of Piperazine Citrate per mL.
Procedure
Apply separate 5-µL portions of
Standard solution 1, Standard solution 2, Standard solution 3, Resolution solution, Test solution 1, and
Test solution 2 to a suitable thin-layer chromatographic plate (see
Chromatography
621
), coated with a 0.25-mm layer of chromatographic silica gel. Allow the spots to dry, and develop the chromatograms in a solvent system consisting of a freshly prepared mixture of acetone and 13.5 N ammonium hydroxide (80:20) until the solvent front has moved about three-fourths of the length of the plate. Remove the plate from the developing chamber, mark the solvent front, and dry the plate at 105

. Spray the plate with a 0.3% (w/v) solution of ninhydrin in a mixture of butyl alcohol and glacial acetic acid (100:3). Spray the plate again with a 0.15% (w/v) solution of ninhydrin in dehydrated alcohol, dry the plate at 105

for 10 minutes, and examine the plate: any secondary spot in the chromatogram obtained from
Test solution 1 is not more intense than the principal spot in the chromatogram obtained from
Standard solution 2 (0.25%). Spray the plate with 0.1 N iodine TS, allow to stand for 10 minutes, and examine the plate: any spot corresponding to triethylenediamine in the chromatogram obtained from
Test solution 1 is not more intense than the principal spot in the chromatogram obtained from
Standard solution 3 (0.25%). In a valid test, the chromatogram obtained from the
Resolution solution shows a spot due to triethylenediamine clearly separated from the principal spot. Disregard any spot at the origin of any chromatogram.
USP32
Change to read:
Assay
Dissolve about 200 mg of Piperazine Citrate, accurately weighed, in 100 mL of glacial acetic acid,
USP32 warming slightly if necessary to effect solution. Add
crystal violet TS, and titrate with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 10.71 mg of (C
4H
10N
2)
3·2C
6H
8O
7.