Standard solution—
Dissolve an accurately weighed quantity of
USP Pyrilamine Maleate RS in a mixture of methanol and ammonium hydroxide (200:1) to obtain a solution having a known concentration of about 0.4 mg per mL. Quantitatively dilute this solution with the mixture of methanol and ammonium hydroxide (200:1) to obtain
Standard solutions A,
B, and
C having the following compositions:
Standard
solution |
Dilution |
Concentration
(mg of RS
per mL) |
Percentage (%,
for comparison
with test
specimen) |
A
B
C |
(1 in 4)
(3 in 20)
(1 in 20) |
0.1
0.06
0.02 |
0.5
0.3
0.1 |
Procedure—
Apply separately 10 µL of the
Test solution and 10 µL of each of the three
Standard solutions to a suitable thin-layer chromatographic plate (see
Chromatography 
621
) coated with a 0.25-mm layer of chromatographic silica gel mixture.
[NOTE—The plate has been prewashed for 2 hours with
Eluant and dried.
] Allow the spots on the plate to dry. Place the plate in a chromatographic chamber and develop the chromatograms in
Eluant 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 air-dry the plate. View the plate under short-wavelength UV light and compare the intensities of any secondary spots from the chromatogram of the
Test solution with those of the principal spots from the chromatograms of the
Standard solutions. No secondary spot from the chromatogram of the
Test solution is larger or more intense than the principal spot from
Standard solution A (0.5%), and the sum of the intensities of all secondary spots from the
Test solution corresponds to not more than 1.0%.
TEST
2—
Mobile phase—
Prepare a filtered and degassed mixture of 0.01
M ammonium acetate, methanol, and triethylamine (40:60:0.1). Make adjustments, if necessary (see
System Suitability under
Chromatography 621).
Standard solution—
Dissolve an accurately weighed quantity of
USP Pyrilamine Maleate RS in
Mobile phase to obtain a solution having a known concentration of about 0.5 µg per mL.
Test solution—
Transfer about 50 mg of Pyrilamine Maleate, accurately weighed, to a 100-mL volumetric flask, dissolve in and dilute with Mobile phase to volume, and mix.
Chromatographic system
(see
Chromatography 621)—The liquid chromatograph is equipped with a 254-nm detector and a 4.0-mm × 30-cm column that contains packing L11. The flow rate is about 1.0 mL per minute. Chromatograph the
Standard solution, and record the peak responses as directed for
Procedure: the relative standard deviation for replicate injections is not more than 5.0%.
Procedure—
Inject a volume (about 20 µL) of the
Test solution into the chromatograph, run the chromatograph for 25 minutes, record the chromatograms, and measure the peak area responses, but do not measure the maleate peak area response, which elutes near the void volume. Calculate the percentage of each impurity in the portion of pyrilamine taken by the formula:
10,000(C / W)(ri / rS),
in which
C is the concentration, in mg per mL, of
USP Pyrilamine Maleate RS in the
Standard solution; W is the weight, in mg, of the Pyrilamine Maleate taken to prepare the
Test solution; ri is the peak area response for each impurity; and
rS is the response of the
Standard solution: not more than 0.3% of any individual impurity is found, and not more than 1.0% of total impurities is found.
;)
and 103