Bromodiphenhydramine Hydrochloride and Codeine Phosphate Oral Solution

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

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

DOWNLOAD PDF HERE

Bromodiphenhydramine Hydrochloride and Codeine Phosphate Oral Solution contains not less than 90.0 percent and not more than 110.0 percent of the labeled amounts of bromodiphen hydramine hydrochloride (C₁₇H₂₀BrNO · HCl) and codeine phosphate hemihydrate (C₁₈H₂₁NO₃ · H₃PO₄ · 1⁄2H₂O).

Packaging and storage-Preserve in tight, light-resistant containers.

Labeling-Label it to indicate the alcohol content.

USP REFERENCE STANDARDS (11)

USP Bromodiphenhydramine Hydrochloride RS

USP Codeine Phosphate RS

1 Identification

A: Thin-Layer Chromatographic Identification Test (201)

Test solution-Transfer a volume of Oral Solution, equivalent to about 10 mg of codeine phosphate, to a separator, and add 5 mL of water, 5 mL of methylene chloride, and 1 mL of ammonium hydroxide. Shake for 1 minute, allow the layers to separate, and use the clear, lower layer.

Standard solution-Prepare a solution of USP Bromodiphenhydramine Hydrochloride RS and USP Codeine Phosphate RS in methanol containing 10 mg of each per mL.

Developing solvent system: a mixture of alcohol and ammonium hydroxide (49:1).

B: The retention times of the major peaks in the chromatogram of the Assay preparation correspond to those in the chromatogram of the Standard preparation, as obtained in the Assay.

MICROBIAL ENUMERATION TESTS (61), and TESTS FOR SPECIFIED MICROORGANISMS (62)-It meets the requirements of the tests for absence of Salmonella species, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The total aerobic microbial count does not exceed 100 cfu per mL, and the total combined molds and yeasts count does not exceed 50 cfu per mL.

PH (791): between 4.5 and 6.5.

ALCOHOL DETERMINATION, Method // (611): between 4.0% and 6.0% is found.

2 Assay

Diluent-Prepare a mixture of methanol and water (80:20).

Mobile phase-Prepare a filtered and degassed mixture of methanol, water, 0.1 N ammonium hydroxide solution, and 0.1 N ammonium nitrate solution (27:3:2:1). Make adjustments if necessary (see System Suitability under Chromatography (621)).

Standard preparation-Dissolve accurately weighed quantities of USP Bromodiphenhydramine Hydrochloride RS and USP Codeine Phosphate

RS in Diluent, and dilute quantitatively, and stepwise if necessary, with Diluent to obtain a solution having known concentrations of about 100 µg per mL and 80 µg per ml, respectively.

Assay preparation-Using a pipet calibrated "to contain", transfer an accurately measured volume of Oral Solution, equivalent to about 10 mg of bromodiphenhydramine hydrochloride and 8 mg of codeine phosphate, to a 100-mL volumetric flask, dissolve in and dilute with Diluent to volume, and mix.

Chromatographic system (see CHROMATOGRAPHY (621))-The liquid chromatograph is equipped with a 254-nm detector and a 3.9-mm x 30.0-cm column that contains packing L3. The flow rate is about 1.0 mL per minute. Chromatograph the Standard preparation, and record the peak responses as directed for Procedure: the relative retention times are about 1.0 for bromodiphenhydramine and 1.4 for codeine; the resolution, R, between bromodiphenhydramine and codeine is not less than 2.0; and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure-Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the peak responses for bromodiphenhydramine and codeine. Calculate the quantity, in mg, of bromodiphen hydramine hydrochloride (C₁₇H₂₀BrNO · HCl) in each mL of the Oral Solution taken by the formula:

100(C/V)(r_u /r_s )

in which C is the concentration, in mg per ml., of USP Bromodiphenhydramine Hydrochloride RS in the Standard preparation; V is the volume, in mL, of Oral Solution taken to prepare the Assay preparation; andr, and ro are the bromodiphenhydramine peak responses obtained from the

Assay preparation and the Standard preparation, respectively. Calculate the quantity, in mg, of codeine phosphate hemihydrate (C₁₈H₂₁NO₃ · H₃PO₄ · 1⁄2H₂O) in each mL of the Oral Solution taken by the formula:

(406.37/397.36)(100C/V)(r_u /r_s )

in which 406.37 and 397.36 are the molecular weights of codeine phosphate hemihydrate and anhydrous codeine phosphate, respectively; C is the concentration, in mg per mL, of USP Codeine Phosphate RS in the Standard preparation; V is the volume, in mL, of Oral Solution taken to prepare the Assay preparation; and r_u and r_s are the codeine peak responses obtained from the Assay preparation and the Standard preparation, respectively