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

USP Reference standards 11—
USP Meperidine Hydrochloride RS.

Identification— Transfer a volume of Oral Solution, equivalent to about 100 mg of meperidine hydrochloride, to a 125-mL separator, add 40 mL of water and 3 mL of 1 N sodium hydroxide, and extract with three 25-mL portions of n-hexane. Wash the combined extracts with two 20-mL portions of water, discard the water, and then extract with three 25-mL portions of 0.1 N hydrochloric acid. Transfer the extracts to a 100-mL volumetric flask, dilute with 0.1 N hydrochloric acid to volume, and mix: the UV absorption spectrum of this solution exhibits maxima and minima at the same wavelengths as that of a similar preparation of USP Meperidine Hydrochloride RS, concomitantly measured.

Uniformity of dosage units 905—

Deliverable volume 698—

pH 791: between 3.5 and 4.1.

Assay— Transfer an accurately measured volume of Oral Solution, equivalent to about 250 mg of meperidine hydrochloride, to a separator, and add 3 mL of 1 N sodium hydroxide. Extract with five 20-mL portions of chloroform, and filter the extracts through a pledget of cotton into a 250-mL conical flask. Wash the cotton with 5 mL of chloroform, and add the washing to the combined filtrates. Add 10 mL of glacial acetic acid and 2 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a blue endpoint. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 28.38 mg of meperidine hydrochloride (C15H21NO2·HCl).

Topic/Question	Contact	Expert Committee
Monograph	Clydewyn M. Anthony, Ph.D. Scientist 1-301-816-8139	(MDCCA05) Monograph Development-Cough Cold and Analgesics
Reference Standards	Lili Wang, Technical Services Scientist 1-301-816-8129 RSTech@usp.org

USP32–NF27 Page 2882