TY - JOUR T1 - AN ULTRAVIOLET SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF THEOPHYLLINE AND THEOBROMINE IN BLOOD AND TISSUES JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 283 LP - 291 VL - 97 IS - 3 AU - JEROME A. SCHACK AU - SAMUEL H. WAXLER Y1 - 1949/11/01 UR - http://jpet.aspetjournals.org/content/97/3/283.abstract N2 - 1. A simple, rapid and accurate ultraviolet spectrophotometric method for the determination of theophylline and theobromine in biological fluids has been developed. 2. The method offers satisfactory precision and a sensitivity of 1.0 microgm. per cc. 3. Application of the method to the tissue of rabbits and mice has been shown. 4. Theophylline has been demonstrated to be restricted to the plasma of the circulating blood. 5. Theophylline has been demonstrated to be very loosely bound to the plasma proteins. 6. The tissue level of theophylline following intravenous administration has been found to parallel the blood level in its rate of fall. 1949 by The American Society for Pharmacology and Experimental Therapeutics ER -