Papaverine Hydrochloride
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C20H21NO4·HCl 375.85

Isoquinoline, 1-[(3,4-dimethoxyphenyl)methyl]-6,7-dimethoxy-, hydrochloride.
6,7-Dimethoxy-1-veratrylisoquinoline hydrochloride [61-25-6].
» Papaverine Hydrochloride contains not less than 98.5 percent and not more than 100.5 percent of C20H21NO4·HCl, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers. Store at 25, excursions permitted between 15 and 30.
Completeness of solution— A 1 in 15 solution in chloroform is clear and free from undissolved solid.
B: Ultraviolet Absorption 197U
Solution: 2.5 µg per mL.
Medium: 0.1 N hydrochloric acid.
Absorptivities at 251 nm, calculated on the dried basis, do not differ by more than 3.0%.
C: A solution (1 in 50) responds to the tests for Chloride 191.
pH 791: between 3.0 and 4.5, in a solution (1 in 50).
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Limit of cryptopine, thebaine, or other organic impurities— Dissolve 50 mg in 2 mL of sulfuric acid in a small test tube: the resulting solution is not more yellow-brown in color than Matching Fluid S (see Readily Carbonizable Substances Test 271), and it is not more pink than a standard prepared, in equal volume, by diluting 3.0 mL of 0.1 N potassium permanganate with water to 1000 mL.
Assay— Dissolve about 700 mg of Papaverine Hydrochloride, accurately weighed, in 80 mL of glacial acetic acid; add 10 mL of mercuric acetate TS and 1 drop of crystal violet TS; and titrate with 0.1 N perchloric acid VS to a blue-green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 37.59 mg of C20H21NO4·HCl.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Sujatha Ramakrishna, Ph.D.
(MDCV05) Monograph Development-Cardiovascular
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3205
Pharmacopeial Forum: Volume No. 29(5) Page 1551
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.