Assay—
Transfer 1.0 mL of Injection to a 200-mL volumetric flask, and dilute with water to volume. Pipet 3 mL of this solution into a separator, add 10 mL of water, and render alkaline with 6 N ammonium hydroxide. Extract the alkaloid with successive 5-mL portions of chloroform, and evaporate the extracts to dryness. Dissolve the residue in 0.1 N hydrochloric acid, and dilute with the same medium to 100.0 mL. Concomitantly determine the absorbances of this solution and of a Standard solution of
USP Papaverine Hydrochloride RS in 0.1 N hydrochloric acid having a known concentration of about 4.5 µg per mL in 1-cm cells at the wavelength of maximum absorbance at about 251 nm, with a suitable spectrophotometer, using 0.1 N hydrochloric acid as the blank. Calculate the quantity, in mg, of C
20H
21NO
4·HCl in the portion of Injection taken by the formula:
6.67C(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Papaverine Hydrochloride RS in the Standard solution, and
AU and
AS are the absorbances of the solution from the Injection and the Standard solution, respectively.
for 2 hours: it responds to Identification test A under Papaverine Hydrochloride.
85
—
It contains not more than 2.9 USP Endotoxin Units per mg of papaverine hydrochloride.