Standard preparations
Dissolve 
USP Triprolidine Hydrochloride RS in chloroform, and mix to obtain a solution having a known concentration of 1.0 mg per mL. Dilute quantitatively with chloroform to obtain four diluted 
Standard preparations (
A, 
B, 
C, and 
D) having the following compositions: 
Standard 
 
preparation | 
Dilution | 
Concentration (µg RS per mL) | 
Percentage (%, for comparison with test  specimen) | 
| A | 
 (1 in 5) | 
200 | 
2.0 | 
| B | 
 (15 in 100) | 
150 | 
1.5 | 
| C | 
 (1 in 10) | 
100 | 
1.0 | 
| D | 
 (5 in 100) | 
50 | 
0.5 | 
 
 
Procedure
Apply separately 5 µL of the 
Test preparation and 5 µL of each of the eight diluted 
Standard  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, protected from light, in a solvent system consisting of a mixture of chloroform and diethylamine (95:5) 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. Examine the plate under long- and short-wavelength UV light. 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 intensity of the 
Z-isomer triprolidine hydrochloride spot (
RF value about 1.2 relative to the 
RF value for triprolidine hydrochloride) obtained from the 
Test preparation corresponds to not more than 2.0%, and the sum of the intensities of all secondary spots obtained from the 
Test preparation corresponds to not more than 3.0%.