Identification
Transfer a portion of ground Tablet powder,equivalent to about 2mg of aminopentamide,to a separator,add 20mLof water and 3mLof 10Nsodium hydroxide,and mix.Extract with two 20-mLportions of methylene chloride,and evaporate the combined methylene chloride extracts to a volume of about 0.5mL.Transfer a few drops of the chloroform concentrate to a KRS-5plate,and allow to dry.Record the IRabsorption spectrum by the attenuated total reflectance technique (see
Spectrophotometry and Light-Scattering á851ñ).The spectrum thus obtained exhibits maxima only at the same wavelengths as that of a similar preparation of
USP Aminopentamide Sulfate RS,concomitantly measured.
Loss on drying á731ñ
Dry about 1g of powdered Tablets,accurately weighed,in vacuum at a pressure of 5mm of mercury or less at 60

for 3hours:it loses not more than 4.0%of its weight.
Assay
Mobile phase
Transfer 14.4g of sodium lauryl sulfate to a 500-mLvolumetric flask,add 100mLof glacial acetic acid,dilute with water to volume,mix,and pass through a filter having a 0.5-µm or finer porosity.Transfer 50mLof this solution to a 1000-mLvolumetric flask,add 350mLof methanol and 350mLof acetonitrile,dilute with water to volume,and mix.Filter and degas before use.Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Standard preparation
Quantitatively dissolve an accurately weighed quantity of
USP Aminopentamide Sulfate RSin
Mobile phaseto obtain a solution having a known concentration of about 0.02mg per mL.
Assay preparation
Weigh and finely powder not fewer than 10Tablets.Transfer an accurately weighed portion of the powder,equivalent to about 0.2mg of aminopentamide,to a suitable flask.Add 10.0mLof Mobile phase,sonicate for 5minutes,and stir by mechanical means for about 10minutes.Pass this mixture through a filter having a 0.5-µm or finer porosity,discarding the first 5mLof the filtrate.Use the clear filtrate as the Assay preparation.
Chromatographic system (see Chromatography á621ñ)
The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm ×30-cm column that contains packing L1,and is maintained at a constant temperature of about 40

.The flow rate is about 1mLper minute.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the column efficiency is not less than 900theoretical plates;and the relative standard deviation for replicate injections is not more than 2%.
Procedure
Separately inject equal volumes (about 50µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the quantity,in mg,of aminopentamide sulfate (C
19H
24N
2O·H
2SO
4)in the portion of Tablets taken by the formula:
10C(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Aminopentamide Sulfate RSin the
Standard preparation;and
rUand
rSare the aminopentamide peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.