Standard preparations
Dissolve an accurately weighed quantity of
USP Phenylephrine Hydrochloride RS in methanol to obtain a solution having a known concentration of 1 mg per mL. Quantitatively dilute with methanol to obtain
Standard preparations having the following compositions:
Standard Preparation |
Dilution |
Concentration (µg RS per mL) |
Percentage (%, for comparison with test specimen) |
A |
(1 in 2) |
500 |
1.0 |
B |
(1 in 4) |
250 |
0.5 |
C |
(1 in 10) |
100 |
0.2 |
D |
(1 in 20) |
50 |
0.1 |
Procedure
Apply separately 5 µL of the
Test preparation and 5 µL of each
Standard preparation to a suitable thin-layer chromatographic plate (see
Chromatography 621) coated with a 0.25-mm layer of chromatographic silica gel mixture. Position the plate in a chromatographic chamber and develop the chromatograms in a solvent system consisting of a mixture of
n-butyl alcohol, water, and formic acid (7:2:1) 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 allow the solvent to evaporate in warm, circulating air. Examine the plate under short-wavelength UV light. Then spray the plate with a saturated solution of
p-nitrobenzenediazonium tetrafluoroborate followed by sodium carbonate solution (1 in 10). Compare the intensities of any secondary spots observed in the chromatogram of the
Test preparation with those of the principal spots in the chromatograms of the
Standard preparations: the sum of the intensities of secondary spots obtained from the
Test preparation corresponds to not more than 1.0% of related compounds, with no single impurity corresponding to more than 0.5%.