Aminophylline Injection
»Aminophylline Injection is a sterile solution of Aminophylline in Water for Injection,or is a sterile solution of Theophylline in Water for Injection prepared with the aid of Ethylenediamine.It contains,in each mL,an amount of aminophylline equivalent to not less than 93.0percent and not more than 107.0percent of the labeled amount of anhydrous theophylline (C7H8N4O2).
Aminophylline Injection may contain an excess of Ethylenediamine,but no other substance may be added for the purpose of pHadjustment.
NOTE—Do not use the Injection if crystals have separated.
Packaging and storage— Preserve in single-dose containers from which carbon dioxide has been excluded,preferably of Type Iglass,protected from light.
Labeling— Label the Injection to state the content of anhydrous theophylline.
Identification—
A: Dilute a volume of Injection,equivalent to about 500mg of aminophylline,with water to about 20mL,and add,with constant stirring,1mLof 3Nhydrochloric acid or enough to precipitate the theophylline completely.Filter:the filtrate responds to Identificationtest Cunder Aminophylline.
B: Wash the precipitate of theophylline with a small portion of cold water,and dry at 105for 1hour:the theophylline so obtained melts between 270and 274,and responds to Identificationtest Bunder Aminophylline.
Bacterial endotoxins á85ñ— It contains not more than 1.0USP Endotoxin Unit per mg of aminophylline.
pHá791ñ: between 8.6and 9.0.
Particulate matter á788ñ: meets the requirements for small-volume Injections.
Ethylenediamine content— Accurately measure a volume of Injection,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 Injection contains between 166mg and 192mg of ethylenediamine (C2H8N2)per g of C7H8N4O2found in the Assay.
Other requirements— It meets the requirements under Injections á1ñ.
Assay—
Mobile phase,Diluent,Standard preparation,Resolution solution,and Chromatographic system— Proceed as directed in the Assayunder Aminophylline.
Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 100mg of theophylline,to a 100-mLvolumetric flask,dilute with Diluentto volume,and mix.Pipet 4mLof this solution into a 50-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 the portion of Injection taken by the formula:
1250C(rU/rS),
in which Cis the concentration,in mg per mL,of USP Theophylline RSin the Standard preparation;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