Diphenoxylate Hydrochloride
(dye'' fen ox' i late hye'' droe klor' ide).
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C30H32N2O2·HCl 489.05

4-Piperidinecarboxylic acid, 1-(3-cyano-3,3-diphenylpropyl)-4-phenyl-, ethyl ester, monohydrochloride.
Ethyl 1-(3-cyano-3,3-diphenylpropyl)-4-phenylisonipecotate monohydrochloride [3810-80-8].
» Diphenoxylate Hydrochloride contains not less than 98.0 percent and not more than 102.0 percent of C30H32N2O2·HCl, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
USP Reference standards 11
USP Diphenoxylate Hydrochloride RS Click to View Structure
Solution: 500 µg per mL.
Medium: hydrochloric acid in methanol (1 in 1000).
C: A saturated solution responds to the tests for Chloride 191.
Melting range 741: between 220 and 226.
Loss on drying 731 Dry it at 105 for 2 hours: it loses not more than 0.5% of its weight.
Ordinary impurities 466
Test solution: chloroform.
Standard solution: chloroform.
Eluant: a mixture of chloroform, cyclohexane, dehydrated alcohol, and formic acid (50:40:10:1).
Visualization: 17; then examine the plate immediately under short-wavelength UV light.
Limits— The sum of the intensities of all secondary spots obtained from the Test solution corresponds to not more than 1.0%.
Assay— Dissolve about 300 mg of Diphenoxylate Hydrochloride, accurately weighed, in 75 mL of glacial acetic acid, add 4 mL of mercuric acetate TS, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Each mL of 0.1 N perchloric acid is equivalent to 48.91 mg of C30H32N2O2·HCl.
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Monograph Elena Gonikberg, Ph.D.
Principal Scientific Liaison
(SM32010) Monographs - Small Molecules 3
Reference Standards RS Technical Services
USP35–NF30 Page 2934