Identification
Transfer 10mLof the Injection to a separator,add sodium hydroxide TSuntil alkaline to litmus,and extract with 25mLof chloroform.Transfer a few drops of the chloroform extract 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.
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 water to obtain a solution having a known concentration equivalent to the labeled concentration of aminopentamide sulfate in the Injection.
Assay preparation
Use the undiluted Injection.
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 L1and 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 tailing factor is not more than 2.5;and the relative standard deviation for replicate injections is not more than 2%.
Procedure
Separately inject equal volumes (about 20µL)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 each mLof the Injection taken by the formula:
C(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.