Identification—
Transfer a portion of ground Tablet powder, equivalent to about 2 mg of aminopentamide, to a separator, add 20 mL of water and 3 mL of 10 N sodium hydroxide, and mix. Extract with two 20-mL portions of methylene chloride, and evaporate the combined methylene chloride extracts to a volume of about 0.5 mL. Transfer a few drops of the chloroform concentrate to a KRS-5 plate, and allow to dry. Record the IR absorption spectrum by the attenuated total reflectance technique (see
Spectrophotometry and Light-Scattering 
851
). 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 731—
Dry about 1 g of powdered Tablets, accurately weighed, in vacuum at a pressure of 5 mm of mercury or less at 60
for 3 hours: it loses not more than 4.0% of its weight.
Assay—
Mobile phase—
Transfer 14.4 g of sodium lauryl sulfate to a 500-mL volumetric flask, add 100 mL of glacial acetic acid, dilute with water to volume, mix, and pass through a filter having a 0.5-µm or finer porosity. Transfer 50 mL of this solution to a 1000-mL volumetric flask, add 350 mL of methanol and 350 mL of acetonitrile, dilute with water to volume, and mix. Filter and degas before use. Make adjustments if necessary (see
System Suitability under
Chromatography 621).
Standard preparation—
Quantitatively dissolve an accurately weighed quantity of
USP Aminopentamide Sulfate RS in
Mobile phase to obtain a solution having a known concentration of about 0.02 mg per mL.
Assay preparation—
Weigh and finely powder not fewer than 10 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 0.2 mg of aminopentamide, to a suitable flask. Add 10.0 mL of Mobile phase, sonicate for 5 minutes, and stir by mechanical means for about 10 minutes. Pass this mixture through a filter having a 0.5-µm or finer porosity, discarding the first 5 mL of the filtrate. Use the clear filtrate as the Assay preparation.
Chromatographic system (see Chromatography 621)—
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 1 mL per minute. Chromatograph the
Standard preparation, and record the peak responses as directed for
Procedure: the column efficiency is not less than 900 theoretical plates; and the relative standard deviation for replicate injections is not more than 2%.
Procedure—
Separately inject equal volumes (about 50 µL) of the
Standard preparation and the
Assay preparation into 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
C is the concentration, in mg per mL, of
USP Aminopentamide Sulfate RS in the
Standard preparation; and
rU and
rS are the aminopentamide peak responses obtained from the
Assay preparation and the
Standard preparation, respectively.
not more than 10 minutes, simulated gastric fluid TS being substituted for water in the test.