Cyproheptadine Hydrochloride
(sye'' proe hep' ta deen hye'' droe klor' ide).
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C21H21N·HCl·1½H2O 350.88

Piperidine, 4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-methyl-, hydrochloride, sesquihydrate.
4-(5H-Dibenzo[a,d]cyclohepten-5-ylidene)-1-methylpiperidine hydrochloride sesquihydrate [41354-29-4].

Anhydrous 323.87 [969-33-5].
» Cyproheptadine Hydrochloride contains not less than 98.5 percent and not more than 100.5 percent of C21H21N·HCl, calculated on the anhydrous basis.
Packaging and storage— Preserve in well-closed containers.
USP Reference standards 11
USP Cyproheptadine Hydrochloride RS
Identification—
B: Ultraviolet Absorption 197U
Solution: 16 µg per mL.
Medium: alcohol.
Absorptivities at 286 nm do not differ by more than 3.0%.
C: Dissolve 100 mg of Cyproheptadine Hydrochloride in 10 mL of methanol. Place 1 drop of the solution on a filter paper, dry, and view under short-wavelength UV light: a bright blue fluorescence is observed.
Acidity— Dissolve 1.0 g of Cyproheptadine Hydrochloride in 25 mL of methanol, add methyl red TS, and titrate with 0.10 N sodium hydroxide: not more than 0.15 mL is required (0.05% as HCl).
Water, Method I 921: between 7.0% and 9.0%.
Residue on ignition 281: not more than 0.1%.
Assay— Dissolve about 650 mg of Cyproheptadine Hydrochloride, accurately weighed, in 50 mL of glacial acetic acid, heating to dissolve. Cool, add 10 mL of mercuric acetate TS, 0.5 mL of acetic anhydride, and 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 32.39 mg of C21H21N·HCl.
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