Packaging and storage— Preserve in well-closed containers.

Identification— Add the residue obtained in the Assayto 50mLof water:the solution responds to the Identificationtests under Methylcellulose.

Disintegration á701ñ: 30minutes.

Uniformity of dosage units á905ñ: meet the requirements.

Assay— Weigh and finely powder not less than 20Tablets.Weigh accurately a portion of the powder,equivalent to about 500mg of methylcellulose,and transfer to a tared,fine fritted-glass,low-form,30-mLcrucible having a fitted crucible lid.Add 20mLof alcohol,and macerate the solid for about 5minutes,mixing intermittently with a glass stirring rod.Repeat the extraction with ten consecutive 10-mLportions of alcohol.Test for completeness of extraction by evaporating the last alcohol extract on a steam bath to dryness,taking up the residue in about 1mLof water,and adding this to 5mLof hot alkaline cupric tartrate TS(no red precipitate of cuprous oxide is formed within 5minutes).If a precipitate is formed,continue with the alcohol extractions until the test is negative.Wash the completely extracted residue with a 10-mLportion of ether,using suction to drain off the liquid.Dry the residue in the crucible in a drying oven at 105to constant weight.Weigh the crucible with the crucible lid in place.The weight of residue is the weight of methylcellulose present in the portion of powdered Tablets taken.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 1258

Phone Number:1-301-816-8323