Packaging and storage— Preserve in tight containers.

Identification— Mix 2 mL of Oral Suspension with 2 mL of acetone and 2 mL of a 1 in 100 solution of furfural in glacial acetic acid, add 5 mL of hydrochloric acid, and shake: a purple color is produced, and, on standing, it changes to blue, then to blue-black, and finally to black-brown.

Uniformity of dosage units 905—

Deliverable volume 698—

Assay— Transfer an accurately measured volume of Oral Suspension, equivalent to about 400 mg of meprobamate, to a separator, and completely extract the meprobamate with 20-mL portions of chloroform, filtering the extracts through a pledget of cotton enclosed in glass wool that previously has been moistened with chloroform. Collect the filtrate in a conical flask, add several glass beads to the flask, and evaporate on a steam bath to dryness. To the residue add 20 mL of water, heat on a steam bath for several minutes, then add 40 mL of hydrochloric acid, and reflux for 90 minutes. Remove the condenser, and continue boiling until the volume is reduced to about 20 mL. Cool to room temperature, add 50 mL of water, and cool in an ice bath. Add 1 drop of methyl red TS, and, while cooling continuously, cautiously neutralize with sodium hydroxide solution (4 in 10) until the indicator begins to change color. Add hydrochloric acid, if necessary, to restore the pink color, then carefully neutralize with 0.1 N sodium hydroxide VS. Add 30 mL of neutral formaldehyde solution (18% w/w), and titrate with 0.1 N sodium hydroxide VS until the solution becomes yellow. Add 0.2 mL of phenolphthalein TS, and continue the titration with 0.1 N sodium hydroxide VS to a distinct pink color. Perform a blank determination, and make any necessary correction. Each mL of the total volume of 0.1 N sodium hydroxide consumed after the addition of the formaldehyde solution is equivalent to 10.91 mg of C9H18N2O4.

Topic/Question	Contact	Expert Committee
Monograph	Ravi Ravichandran, Ph.D. Senior Scientist 1-301-816-8330	(MDPP05) Monograph Development-Psychiatrics and Psychoactives

USP32–NF27 Page 2888