Packaging and storage— Preserve in tight containers.

Identification— Mix 2mLof Oral Suspension with 2mLof acetone and 2mLof a 1in 100solution of furfural in glacial acetic acid,add 5mLof 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 á905ñ—

Deliverable volume á698ñ—

Assay— Transfer an accurately measured volume of Oral Suspension,equivalent to about 400mg of meprobamate,to a separator,and completely extract the meprobamate with 20-mLportions 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 20mLof water,heat on a steam bath for several minutes,then add 40mLof hydrochloric acid,and reflux for 90minutes.Remove the condenser,and continue boiling until the volume is reduced to about 20mL.Cool to room temperature,add 50mLof water,and cool in an ice bath.Add 1drop of methyl red TS,and,while cooling continuously,cautiously neutralize with sodium hydroxide solution (4in 10)until the indicator begins to change color.Add hydrochloric acid,if necessary,to restore the pink color,then carefully neutralize with 0.1Nsodium hydroxide VS.Add 30mLof neutral formaldehyde solution (18%w/w),and titrate with 0.1Nsodium hydroxide VSuntil the solution becomes yellow.Add 0.2mLof phenolphthalein TS,and continue the titration with 0.1Nsodium hydroxide VSto a distinct pink color.Perform a blank determination,and make any necessary correction.Each mLof the total volume of 0.1Nsodium hydroxide consumed after the addition of the formaldehyde solution is equivalent to 10.91mg of C9H18N2O4.

Expert Committee:(PA3)Pharmaceutical Analysis 3

USP28–NF23Page 1214

Phone Number:1-301-816-8165