Methylbenzethonium Chloride Ointment, chemical structure, molecular formula, Reference Standards

Methylbenzethonium Chloride Ointment

»Methylbenzethonium Chloride Ointment contains not less than 90.0percent and not more than 110.0percent of the labeled amount of methylbenzethonium chloride (C28H44ClNO2·H2O).

Packaging and storage— Preserve in collapsible tubes or in tight containers.

USP Reference standards á11ñ— USP Docusate Sodium RS.

Identification— Suspend about 0.5g of Ointment in 10mLof water,add 0.1g of sodium carbonate,1mLof bromophenol blue TS,and 10mLof chloroform,and shake:the chloroform layer is blue.

pHá791ñ: between 5.0and 7.0,in a dispersion of it in carbon dioxide-free water (1in 100).

Assay—

0.0001N Docusate sodium— Prepare as directed for 0.0001N Docusate sodiumin the Assayunder Methylbenzethonium Chloride Lotion.

Procedure— Transfer an accurately weighed portion of Ointment,equivalent to about 0.5mg of methylbenzethonium chloride,to a glass-stoppered,50-mLcylinder,and proceed as directed in the Assayunder Methylbenzethonium Chloride Lotion,beginning with “Add 5mLof chloroform.”

Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist

Expert Committee:(PA7)Pharmaceutical Analysis 7

USP28–NF23Page 1256

Phone Number:1-301-816-8394