Theophylline - DESCRIPTION Theophylline is structurally classified as a methylxanthine. It occurs as a white, odorless, crystalline powder with a bitter taste. Anhydrous theophylline has the chemical name 1H-Purine- 2,6-dione, 3,7-dihydro-1 ,3 -dimethyl-, and is represented by the following structural formula: The molecular formula of anhydrous theophylline is C 7 H 8 N 4 O 2 ...