A
bronchodilator found in
trace amounts in
tea. It is a dimethylxanthine, specifically 1,3-Dimethylxanthine, represented by the
empirical formula C
7H
8N
4O
2. It is a
white crystalline
powder and has a
water solubility of 0.1 - 0.5 g/100 mL @ 21.5° C. Generally, tea contains 3-4 milligrams of theophylline. It is also available as a
prescription drug in
capsule,
elixir,
oral solution,
tablet, extended-
release capsule, extended-release tablet, and
syrup forms.