Abstract
A sensitive method for the estimation of caffeine in biological material is described. The method is specific in that it does not include transformation products of caffeine in the measurement.
Caffeine is rapidly and essentially completely absorbed from the gastrointestinal tract of man.
Caffeine is almost entirely transformed in man, only about 1 per cent being excreted in the urine. The rate of biotransformation is fairly uniform from subject to subject, the average half-life being 3.5 hours (15 per cent metabolized per hour). The metabolic rate of transformation in dogs is about the same as in man.
Caffeine is distributed in various tissues in approximate proportion to their water content. The drug passes rapidly into the central nervous system.
Although a considerable amount of caffeine accumulates in the body of moderately heavy coffee drinkers during the day, there is no day to day accumulation of the drug.
Footnotes
- Received November 24, 1952.
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