Absorption rate of methylxanthines following capsules, cola and chocolate

Objective: To compare caffeine and theobromine absorption after oral administration of capsules, cola beverage and chocolate candy. Methods: Three males and four females who abstained from methylxanthines received five methylxanthine-containing treatments: caffeine in capsules (72 mg), administered twice; theobromine in capsules (370 mg); cola beverage (72 mg caffeine) and chocolate candy (72 mg caffeine and 370 mg theobromine). Plasma methylxanthine levels were assayed from samples collected before and 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, and 3.0 h after caffeine capsule and cola treatments and, additionally, at 4.0 and 6.0 h after theobromine capsule and chocolate treatments. Results: Caffeine plasma concentrations increased rapidly and peaked at approximately 30 min following both capsule treatments 1 (C(max): 1.93 μg·ml^-1); and 2 (C(max): 2.05 μg·ml^-1). Relative to capsules, caffeine absorption from cola and chocolate was delayed and produced lower maximum caffeine plasma concentrations which peaked 1.5-2.0 h after treatment (For cola, C(max): 1.57 μg·ml^-1); and for chocolate, C(max): 1.50 μg·ml^-1. Theobromine plasma concentrations peaked approximately 3 h after capsule administration (C(max): 6.72 μg·ml^-1). Relative to capsules, theobromine absorption from chocolate was more rapid and produced higher maximum theobromine plasma concentrations which peaked approximately 2 h after treatment (C(max): 8.05 μg·ml^-1). Conclusions: The results suggest that a usual dietary portion of the cola or chocolate used in this study would produce behaviorally discriminable plasma levels of caffeine in most subjects and of theobromine in at least one subject.