Aminophylline Injection, USP is a sterile, nonpyrogenic solution of aminophylline in water for injection. Aminophylline (dihydrate) is approximately 79% of anhydrous theophylline by weight. Aminophylline Injection is administered by slow intravenous injection or diluted and administered by intravenous infusion.
The solution contains no bacteriostat or antimicrobial agent and is intended for use only as a single-dose injection. When smaller doses are required the unused portion should be discarded.
Aminophylline is a 2:1 complex of theophylline and ethylenediamine. Theophylline is structurally classified as a methylxanthine. Aminophylline occurs as a white or slightly yellowish granule or powder, with a slight ammoniacal odor. Aminophylline has the chemical name 1H-Purine-2, 6-dione, 3,7-dihydro-1,3-dimethyl-, compound with 1,2-ethanediamine (2:1). The structural formula of aminophylline (dihydrate) is as follows:
The molecular formula of aminophylline dihydrate is C16H24N10O4 • 2(H2O) with a molecular weight of 456.46.
Aminophylline Injection, USP contains aminophylline (calculated as the dihydrate) 25 mg/mL (equivalent to 19.7 mg/mL anhydrous theophylline) prepared with the aid of ethylenediamine. The solution may contain an excess of ethylenediamine for pH adjustment. pH is 8.8 (8.6 to 9.0). The osmolar concentration is 0.17 mOsmol/mL (calc.).