Pentazocine Hydrochloride
C19H27NO·HCl 321.88

2,6-Methano-3-benzazocin-8-ol, 1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(3-methyl-2-butenyl)-, hydrochloride, (2,6,11R*)-.
(2R*,6R*,11R*)-1,2,3,4,5,6-Hexahydro-6,11-dimethyl-3-(3-methyl-2-butenyl)-2,6-methano-3-benzazocin-8-ol hydrochloride [64024-15-3].
» Pentazocine Hydrochloride contains not less than 98.0 percent and not more than 102.0 percent of C19H27NO·HCl, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers.
Solution: 80 µg per mL of pentazocine.
Medium: 0.01 N hydrochloric acid.
Absorptivities at 278 nm, calculated on the dried basis, do not differ by more than 3.0%. [note—The molecular weight of pentazocine (C19H27NO) is 285.43.]
B: Dissolve 50 mg of USP Pentazocine RS in 25 mL of 0.01 N hydrochloric acid in a separator, and use this in place of the Standard solution specified under Identification—Organic Nitrogenous Bases 181: Pentazocine Hydrochloride meets the requirements of the test.
C: A solution (1 in 100) responds to the tests for Chloride 191.
Loss on drying 731 Dry it at a pressure not exceeding 5 mm of mercury at 100 to constant weight: it loses not more than 1.0% of its weight.
Residue on ignition 281: not more than 0.2%.
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol, USP Pentazocine RS being used.
Eluant: a mixture of chloroform, methanol, and isopropylamine (94:3:3).
Visualization— Heat the plate in an oven at 105 for 15 minutes, cool, follow with visualization technique 17, and view under short-wavelength UV light.
Limits— The total of any ordinary impurities observed does not exceed 1.0%.
Assay— Dissolve about 650 mg of Pentazocine Hydrochloride, accurately weighed, in 50 mL of glacial acetic acid, and add 10 mL of mercuric acetate TS. Add 1 drop of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a green endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 32.19 mg of C19H27NO·HCl.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Clydewyn M. Anthony, Ph.D.
(MDCCA05) Monograph Development-Cough Cold and Analgesics
Reference Standards Lili Wang, Technical Services Scientist
USP32–NF27 Page 3243