Aminophylline Oral Solution
»Aminophylline Oral Solution is an aqueous solution of Aminophylline,prepared with the aid of Ethylenediamine.It contains an amount of aminophylline equivalent to not less than 90.0percent and not more than 110.0percent of the labeled amount of anhydrous theophylline (C7H8N4O2).
Aminophylline Oral Solution may contain an excess of ethylenediamine,but no other substance may be added for the purpose of pHadjustment.
Packaging and storage— Preserve in tight containers.
Labeling— Label the Oral Solution to state the content of anhydrous theophylline.
Identification—
A: Place a volume of Oral Solution,equivalent to about 500mg of aminophylline,in a suitable container,and add,with constant stirring,1mLof 3Nhydrochloric acid or an amount sufficient to precipitate the theophylline completely.Filter (retain the filtrate),wash the precipitate with small portions of cold water until free from chloride,and dry at 105for 1hour:the theophylline so obtained melts between 270and 274.
B: The filtrate from Identificationtest Aresponds to Identificationtest Cunder Aminophylline.
pHá791ñ: between 8.5and 9.7.
Ethylenediamine content— Accurately measure a volume of Oral Solution,equivalent to about 500mg of aminophylline,and dilute with water,if necessary,to make about 30mL.Add methyl orange TS,and titrate with 0.1Nhydrochloric acid VS.Each mLof 0.1Nhydrochloric acid is equivalent to 3.005mg of C2H8N2.The Oral Solution contains between 176mg and 283mg of ethylenediamine (C2H8N2)per g of C7H8N4O2found in the Assay.
Assay—
Mobile phase,Diluent,Standard preparation,Resolution solution,and Chromatographic system— Prepare as directed in the Assayunder Aminophylline.
Assay preparation— Transfer an accurately measured volume of Oral Solution,equivalent to about 18mg of anhydrous theophylline,to a 250-mLvolumetric flask,dilute with Diluentto volume,and mix.
Procedure— Proceed as directed for Procedurein the Assayunder Aminophylline.Calculate the quantity,in mg,of theophylline (C7H8N4O2)in each mLof the Oral Solution taken by the formula:
250(C/V)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Theophylline RSin the Standard preparation;Vis the volume,in mL,of Oral Solution taken;and rUand rSare the theophylline peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 129
Phone Number:1-301-816-8379