Food‐induced gastric retention and absorption of sustained‐release procainamide

The relationship between variations in the gastric residence time and the absorption of procainamide from a waxed matrix, sustained‐release tablet was evaluated in a repeated‐measures study conducted in eight healthy men. Subjects received sustained‐release procainamide together with a Heidelberg capsule, alone and with food. Blood and urine samples were collected for up to 24 hours before and after gastric emptying of the Heidelberg capsule for procainamide and N ‐acetylprocainamide concentration determinations. The gastric residence time of the Heidelberg capsule was prolonged by food (median 3.5 [range 1.5 to 10.0] vs. 1.0 [range 0.5 to 2.5] hours; P < 0.02). No significant differences (median [range]; fasting vs. fed) in procainamide lag time (0.5 [0.5 to 1.0] vs. 0.5 [0.5 to 1.5] hours) or time at which peak procainamide plasma concentrations occurred (2.9 [1.0 to 4.3] vs. 2.8 [2.0 to 6.0] hours) were evident with feeding. Slight increases in procainamide AUC and peak concentrations occurred with feeding. No alteration in the extent of urinary excretion of procainamide or N ‐acetylprocainamide occurred with feeding. Thus food did not influence the absorption of sustained‐release procainamide despite apparent prolonged gastric retention. Clinical Pharmacology and Therapeutics (1987) 42, 45–49; doi: 10.1038/clpt.1987.106