Packaging and storage—
Preserve in tight containers.
pH 
791
:
between 4.5 and 5.5, in a solution (1 in 40).
Sulfate 221—
A 2.0-g portion shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid (0.01%).
Chloride content—
Transfer about 350 mg, previously dried and accurately weighed, to a 250-mL beaker. Add about 125 mL of water and 10 drops of sulfuric acid, and stir for 15 minutes with a magnetic stirrer. Titrate the solution potentiometrically with 0.1 N silver nitrate VS, using a silver-mercurous sulfate electrode system with a saturated salt bridge of potassium sulfate. Each mL of 0.1 N silver nitrate is equivalent to 3.545 mg of Cl: the content is between 16.3% and 17.0%.
Heavy metals, Method II 231:
0.001%.
Ordinary impurities 466—
Test solution:
methanol.
Standard solution:
methanol.
Eluant:
a mixture of chloroform, absolute alcohol, and ammonium hydroxide (80:20:1).
Visualization:
1.
Organic volatile impurities, Method I 467:
meets the requirements.
Assay—
Transfer to a 200-mL volumetric flask about 100 mg of Phenmetrazine Hydrochloride, previously dried and accurately weighed. Dissolve in 0.5 N hydrochloric acid, dilute with 0.5 N hydrochloric acid to volume, and mix to obtain the
Assay preparation. Concomitantly determine the absorbances of the
Assay preparation and of a Standard solution of
USP Phenmetrazine Hydrochloride RS, in the same medium having a known concentration of about 500 µg per mL, in 1-cm cells, at the wavelength of maximum absorbance at about 256 nm, with a suitable spectrophotometer, using 0.5 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C
11H
15NO·HCl in the Phenmetrazine Hydrochloride taken by the formula:
0.2C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Phenmetrazine Hydrochloride RS in the Standard solution, and
AU and
AS are the absorbances from the
Assay preparation and the Standard solution, respectively.
;)
for 2 hours, contains not less than 98.0 percent and not more than 102.0 percent of C11H15NO·HCl.