Bromodiphenhydramine Hydrochloride

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₁₇H₂₀BrNO · HCl             370.71

Ethanamine, 2-(4-bromophenyl)phenylmethoxy-N,N-dimethyl-, hydrochloride.

2-(p-Bromo-α-phenylbenzyl)oxy-N,N-dimethylethylamine hydrochloride CAS RN: 1808-12-4; UNII: 202J683U97.

Bromodiphenhydramine Hydrochloride contains not less than 98.0 percent and not more than 101.0 percent of C₁₇H₂₀BrNO · HCl, calculated on the dried basis.

Packaging and storage—Preserve in tight containers.

Packaging and storage-Preserve in tight containers.

USP REFERENCE STANDARDS (11)-

USP Bromodiphenhydramine Hydrochloride RS

1 Identification

Change to read:

A: Spectroscopic Identification Tests (197), Infrared Spectroscopy: 197K _{(CN 1-May-2020)}

Change to read:

B: Spectroscopic Identification Tests (197), Ultraviolet-Visible Spectroscopy: 197U _{(CN 1-May-2020)}

Solution: 15 µg per mL..

Medium: 0.1 N sulfuric acid.

Absorptivities at 228 nm, calculated on the dried basis, do not differ by more than 3.0%.

MELTING RANGE (741): between 148° and 152°.

LOSS ON DRYING (731)-Dry it at 105° for 3 hours; it loses not more than 0.5% of its weight.

2 Assay

Dissolve about 700 mg of Bromodiphenhydramine Hydrochloride, accurately weighed, in 50 ml. of glacial acetic acid, and add 10 mL of benzene and 15 mL of mercuric acetate TS. Add 2 drops 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 37.07 mg of C₁₇H₂₀BrNO · HCl.