Phenyltoloxamine Citrate

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

C₁₇H₂₁NO · C₆H₈O₇ 447.48

N,N-Dimethyl-2-(α-phenyl-o-tolyloxy)ethylamine, citrate (1:1) salt.

2-(2-Dimethylaminoethoxy)diphenylmethane, citrate (1:1) salt

Phenyltoloxamine dihydrogen citrate CAS RN®: 1176-08-5; UNII: 8UE48MJH8M.

Phenyltoloxamine Citrate contains not less than 99.0 percent and not more than 101.0 percent of C₁₇H₂₁NO · C₆H₈O₇, calculated on the dried basis.

1 Packaging and storage

Preserve in well-closed containers. Store at room temperature.

USP Reference standards 〈11〉

USP Phenyltoloxamine Citrate RS

USP Phenyltoloxamine Related Compound A RS

2-(2-Benzylphenoxy)ethylmethylamine hydrochloride.

C₁₆H₁₉NO · HCl 277.79

Change to read:

2 Identification

Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020) .

Melting range, Class 1a 〈741〉: between 137° and 143°.

pH 〈791〉: between 3.2 and 4.2, in a solution (1 in 100).

Loss on drying 〈731〉 - Dry it in vacuum at 80° for 3 hours: it loses not more than 0.5% of its weight.

Residue on ignition 〈281〉: not more than 0.1%.

3 Related compounds

Resolution solution - In a separatory funnel dissolve about 10 mg each of USP Phenyltoloxamine Citrate RS and USP Phenyltoloxamine Related Compound A RS, accurately weighed, in 50 mL of water. Add 5 mL of ammonium hydroxide, and extract with three 10-mL portions of methylene chloride. Combine the extracts, dry the solution over anhydrous sodium sulfate, and gently evaporate to dryness. Dissolve the residue in 20 mL of methylene chloride.

Test solution - In a separatory funnel dissolve about 400 mg of Phenyltoloxamine Citrate, accurately weighed, in 50 mL of water. Proceed as directed for Resolution solution, beginning with “Add 5 mL of ammonium hydroxide.”

Chromatographic system (see Chromatography 〈621〉) - The gas chromatograph is equipped with a split injection system, a flame-ionization detector, and a 0.32-mm × 25-m column coated with a 0.45-μm film of phase G27. The carrier gas is helium, flowing at a rate of about 29 cm per second, with a split flow rate of about 25 mL per minute. The column temperature is programmed as follows. Initially the temperature of the column is equilibrated at 190° for 3 minutes, then the temperature is increased at a rate of 4° per minute to 240°, and maintained at 240° for 8 minutes. The injection port and the detector temperatures are maintained at 280°. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the resolution, R, between phenyltoloxamine and phenyltoloxamine related compound A is not less than 1.5.

Procedure - Inject a volume (about 1 μL) of the Test solution into the chromatograph, record the chromatograms, and measure the peak responses. Calculate the percentage of each impurity in the portion of Phenyltoloxamine Citrate taken by the formula:

100(r_i/r_S)

in which r_i is the peak response of each impurity; and r_S is the sum of the responses of all the peaks, excluding the solvent peaks: not more than 0.2% of phenyltoloxamine related compound A; not more than 0.1% of any other individual impurity; and not more than 1.0% of total impurities is found.

4 Assay

Dissolve about 0.5 g of Phenyltoloxamine Citrate, accurately weighed, in 80 mL of glacial acetic acid, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction (see Titrimetry 〈541〉). Each mL of 0.1 N perchloric acid is equivalent to 44.75 mg of C₁₇H₂₁NO · C₆H₈O₇.