Pyrvinium Pamoate
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C75H70N6O6 1151.40

Quinolinium, 6-(dimethylamino)-2-[2-(2,5-dimethyl-1-phenyl]-1H-pyrrol-[3-yl)ethenyl]-1-methyl-, salt with 4,4¢-methylenebis[3-hydroxy-[2-naphthalenecarboxylic acid] (2:1).
6-(Dimethylamino)-2-[2-(2,5-dimethyl-1-phenylpyrrol-3-yl)vinyl]-1-methylquinolinium 4,4¢-methylenebis[3-hydroxy-2-naphthoate] (2:1) [3546-41-6].
» Pyrvinium Pamoate contains not less than 96.0 percent and not more than 104.0 percent of C75H70N6O6, calculated on the anhydrous basis.
Packaging and storage— Preserve in tight, light-resistant containers.
B: A solution of it in a 1 in 200 solution of glacial acetic acid in methanol, prepared as directed in the Assay, exhibits absorbance maxima at about 358 nm and at about 505 nm, and the ratio A505/A358 is between 1.93 and 2.07.
Water, Method I 921: not more than 6.0%, a 200-mg specimen being used for the test, and a mixture of 10 mL of methanol and 10 mL of chloroform being used as the solvent.
Residue on ignition 281: not more than 0.5%.
Assay— [note—Use low-actinic flasks in preparing the solutions, and otherwise protect the solutions from unnecessary exposure to bright light. Complete the assay without prolonged interruption.] Dissolve about 250 mg of Pyrvinium Pamoate, accurately weighed, in 125 mL of glacial acetic acid in a 250-mL volumetric flask, dilute with methanol to volume, and mix. Transfer 5 mL of this solution to a 500-mL volumetric flask, dilute with methanol to volume, and mix. Similarly dissolve an accurately weighed quantity of USP Pyrvinium Pamoate RS in glacial acetic acid, using 1 mL for each 2 mg taken, and dilute quantitatively and stepwise with methanol to obtain a Standard solution having a known concentration of about 10 µg per mL. Concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 505 nm, with a suitable spectrophotometer, using methanol as the blank. Calculate the quantity, in mg, of C75H70N6O6 in the portion of Pyrvinium Pamoate taken by the formula:
25C(AU / AS)
in which C is the concentration, in µg per mL, of USP Pyrvinium Pamoate RS in the Standard solution, calculated on the anhydrous basis, and AU and AS are the absorbances of the solution of Pyrvinium Pamoate and the Standard solution, respectively.
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Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
(MDAA05) Monograph Development-Antivirals and Antimicrobials
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3455