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 93.0 percent and not more than 107.0 percent 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 pH adjustment.
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 I glass, protected from light.
Labeling— Label the Injection to state the content of anhydrous theophylline.
A: Dilute a volume of Injection, equivalent to about 500 mg of aminophylline, with water to about 20 mL, and add, with constant stirring, 1 mL of 3 N hydrochloric acid or enough to precipitate the theophylline completely. Filter: the filtrate responds to Identification test C under Aminophylline.
B: Wash the precipitate of theophylline with a small portion of cold water, and dry at 105 for 1 hour: the theophylline so obtained melts between 270 and 274, and responds to Identification test B under Aminophylline.
Bacterial endotoxins 85 It contains not more than 1.0 USP Endotoxin Unit per mg of aminophylline.
pH 791: between 8.6 and 9.0.
Particulate matter 788: meets the requirements for small-volume Injections.
Ethylenediamine content— Accurately measure a volume of Injection, equivalent to about 500 mg of aminophylline, and dilute with water, if necessary, to make about 30 mL. Add methyl orange TS, and titrate with 0.1 N hydrochloric acid VS. Each mL of 0.1 N hydrochloric acid is equivalent to 3.005 mg of C2H8N2. The Injection contains between 166 mg and 192 mg of ethylenediamine (C2H8N2) per g of C7H8N4O2 found in the Assay.
Other requirements— It meets the requirements under Injections 1.
Mobile phase, Diluent, Standard preparation, Resolution solution, and Chromatographic system Proceed as directed in the Assay under Aminophylline.
Assay preparation— Transfer an accurately measured volume of Injection, equivalent to about 100 mg of theophylline, to a 100-mL volumetric flask, dilute with Diluent to volume, and mix. Pipet 4 mL of this solution into a 50-mL volumetric flask, dilute with Diluent to volume, and mix.
Procedure— Proceed as directed for Procedure in the Assay under Aminophylline. Calculate the quantity, in mg, of theophylline (C7H8N4O2) in the portion of Injection taken by the formula:
1250C(rU / rS)
in which C is the concentration, in mg per mL, of USP Theophylline RS in the Standard preparation; and rU and rS are the theophylline peak responses obtained from the Assay preparation and the Standard preparation, respectively.
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USP32–NF27 Page 1523