Theophylline is a tea alkaloid that functions as a nonselective PDE4 inhibitor. It can induce smooth muscle relaxation in the bronchiolae of asthma patients. At increased concentrations, theophylline can function as a reprotoxic agent and can cause infertility by incapacitating Sertoli cells. This subsequently causes the premature release of late differentiating spermatogenic cells.
Phosphodiesterase inhibitor; diuretic; cardiac stimulant; muscle relaxant; asthma medication.
Theophylline dissolves in 1 M NH4OH at 50 mg/ml to yield a clear, colorless solution. It is soluble in 0.1 M HCl, 0.1 M NaOH and is slightly soluble(8.3 mg/ml) in water. It is also moderately soluble in ethanol. Furthermore, it is soluble in alcohol (12.5 mg/ml), and chloroform (9.1 mg/ml), alkali hydroxides, ammonia, dilute hydrochloric or nitric acid, but is sparingly soluble in ether.
The solubility of the methylxanthines is low, but can be enhanced by the formation of complexes (usually 1:1) with a wide variety of compounds such as ethylenediamine (to form aminophylline). The formation of complex double salts (caffeine and sodium benzoate) or true salts (like choline theophyllinate, and oxtriphylline) also improves aqueous solubility. These salts or complexes dissociate to yield the parent methylxanthines when dissolved in biological fluids and should not be confused with covalently modified derivatives such asdyphylline (1,3-dimethyl-7-(2,3-dihydroxypropyl)-xanthine).